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fix(config): fix faulty build output w/ --esm flag #3404

Merged
merged 1 commit into from
Jun 3, 2022
Merged

fix(config): fix faulty build output w/ --esm flag #3404

merged 1 commit into from
Jun 3, 2022

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alicewriteswrongs
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@alicewriteswrongs alicewriteswrongs commented Jun 2, 2022 •
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Stencil v2.16.0 introduced a regression, the symptoms of which are described here: #3403. Git bisect showed that this commit was the culprit: cca8951.

What was the regression?

What the user observed is that after upgrading from Stencil version 2.15.2 to version 2.16.0 the build output changed. With 2.15.2, when calling stencil like so:

stencil build --docs --dev --esm

the build output looked something like this:

dist
├── cjs
├── collection
│   ├── components
│   ├── test
│   └── utils
├── esm
│   └── polyfills
├── loader
├── stencil-one
└── types

Whereas after upgrading to 2.16.0 the output looked something like this:

dist
├── stencil-one
└── types

Why did the built output change?

Stencil previously explicitly supported a --esm boolean command-line flag. Before the change to remove the legacy compiler this flag was used to control whether the output would be ES modules or not (I think).

The flag was removed from the supported arguments list in that same commit, however some code that implicitly depended on the argument remained in the codebase, and it was eventually (partially) added back to the codebase later on but, although a change was made to src/cli/parse-flags.ts to support parsing the flag, it was not added to the ConfigFlags interface, which is intended to capture the names and types of all CLI arguments.

Related to this history of the flag being added and removed from Stencil, on src/compiler/config/validate-config.ts there was, prior to the bad commit which introduced this regression, a call to the setBooleanConfig helper that looked like this:

setBooleanConfig(config, 'buildDist', 'esm', !config.devMode || config.buildEs5);

This line creates an undocumented dependency on the --esm command-line flag, where it's presence or absence changes what the value of config.buildDist will be.

This happens because of the implementation of setBooleanConfig, where if a value is passed for the third positional argument it will look at the command-line arguments passed to the Stencil CLI in order to find a value to set on the Config object. The relevant code looks like this:

export const setBooleanConfig = <K extends keyof d.Config>(
  config: d.UnvalidatedConfig,
  configName: (K & keyof d.ConfigFlags) | K,
  flagName: keyof d.ConfigFlags | null,
  defaultValue: d.Config[K]
) => {
  if (flagName) {
    const flagValue = config.flags?.[flagName];
    if (isBoolean(flagValue)) {
      config[configName] = flagValue;
    }
  }

The commit that introduced the regression changed the above call to setBooleanConfig to this:

setBooleanConfig(config, 'buildDist', null, !config.devMode || config.buildEs5);

The user observed the regression because they were using the --esm command-line flag with their project, so on any stencil version <= 2.15.2 the presence of that flag was causing config.buildDist to be set to true, resulting in the expected build output above. In 2.16.0 the behavior of the --esm flag was broken by change from "esm" to null.

Why was the change introduced?

This change was introduced because "esm" was not listed as a supported command-line argument on the ConfigFlags interface and the third position argument to setBooleanConfig has type keyof d.ConfigFlags, so the change to null was in line with what setBooleanConfig expects for its arguments. The commit author (me!) was unsure of whether to make this change or not, and there was some discussion on the PR. Light testing did not turn up the regression because we weren't using the --esm flag.

What is the fix?

The fix is to add esm to the ConfigFlags interface and to revert the bad line in src/compiler/config/validate-config.ts. This will allow anyone who is currently using the --esm flag to keep doing so.

This fix does not deal with whether or not we want to continue supporting the --esm flag — it's possible that a larger refactor to how the buildDist variable is used throughout the codebase is in order — but doing this will unblock any users who are currently depending on Stencil's previous, undocumented behavior.

I think this is the right fix for now, however, because an API change like this should not happen on a minor release, so the behavior of the compiler changing in this way should be viewed as a bug and we should take the steps to restore the old behavior.

Any larger lessons learned?

Part of the reason for the regression was that the CLI argument parsing code does not have a type level contract with the interface into which the CLI args are parsed. In particular, there are lists of supported CLI flags in src/cli/parse-flags.ts but these have no connection with the ConfigFlags interface, which describes the shape of the object into which they are going to be shoved after their values are parsed.

This means that although we have an interface that sort of claims, at least implicitly, because of how it's named, to enumerate the possible / allowed CLI arguments, we aren't actually utilizing the type system to enforce a tighter contract between the parsing code and that interface, so there is a possibility of the arguments declared in one or the other of these two places (the parse-flags.ts code or the ConfigFlags interface) drifting from the other.

To address that root cause I think we should implement something to declare these properties in one place. For instance, we could declare a ReadonlyArray of Boolean flags, another of String flags, and then use types derived from those as keys for the ConfigFlags argument.

Additionally, several of the commits in the history of the repository which had to do with this flag have no discussion, documentation, or context provided for the changes.

Pull request checklist

Please check if your PR fulfills the following requirements:

  • Tests for the changes have been added (for bug fixes / features)
  • Docs have been reviewed and added / updated if needed (for bug fixes / features)
  • Build (npm run build) was run locally and any changes were pushed
  • Unit tests (npm test) were run locally and passed
  • E2E Tests (npm run test.karma.prod) were run locally and passed
  • Prettier (npm run prettier) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

  • Bugfix
  • Feature
  • Refactoring (no functional changes, no api changes)
  • Build related changes
  • Documentation content changes
  • Other (please describe):

Does this introduce a breaking change?

  • Yes
  • No

Well, it fixes a regression that accidentally broke something! So I guess it's undoing an unintentional breaking change.

Testing

I confirmed locally that this fixes the regression, and added some tests around the config flag in question.

@alicewriteswrongs alicewriteswrongs requested a review from a team June 2, 2022 20:21
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github-actions bot commented Jun 2, 2022

--strictNullChecks error report

Typechecking with --strictNullChecks resulted in 2791 errors on this branch.

That's the same number of errors on main, so at least we're not creating new ones!

reports and statistics

Our most error-prone files
Path Error Count
src/compiler/config/test/validate-dev-server.spec.ts 66
src/compiler/config/test/validate-output-www.spec.ts 64
src/compiler/prerender/prerender-main.ts 42
src/screenshot/connector-base.ts 40
src/dev-server/index.ts 39
src/mock-doc/node.ts 37
src/mock-doc/serialize-node.ts 36
src/compiler/sys/tests/in-memory-fs.spec.ts 34
src/testing/puppeteer/puppeteer-browser.ts 34
src/screenshot/screenshot-compare.ts 33
src/testing/jest/jest-config.ts 33
src/compiler/transformers/test/parse-props.spec.ts 32
src/dev-server/server-process.ts 32
src/compiler/config/test/validate-testing.spec.ts 30
src/runtime/vdom/vdom-render.ts 30
src/testing/jest/jest-screenshot.ts 30
src/compiler/sys/typescript/typescript-config.ts 28
src/testing/spec-page.ts 28
src/compiler/build/build-stats.ts 27
src/compiler/output-targets/dist-lazy/generate-lazy-module.ts 26
Our most common errors
Typescript Error Code Count Error messages
TS2532 1130
Error messages Object is possibly 'undefined'.
TS2345 742
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Type 'undefined' is not assignable to type 'Logger'.

Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'string[] | undefined' is not assignable to parameter of type 'string[]'.
Type 'undefined' is not assignable to type 'string[]'.

Argument of type '"g" | "prerender" | "info" | "build" | "docs" | "generate" | "serve" | "telemetry" | "test" | "version" | undefined' is not assignable to parameter of type 'TaskCommand'.
Type 'undefined' is not assignable to type 'TaskCommand'.

Argument of type '"g" | "prerender" | "info" | "build" | "docs" | "generate" | "serve" | "telemetry" | "test" | undefined' is not assignable to parameter of type 'TaskCommand'.
Type 'undefined' is not assignable to type 'TaskCommand'.

Argument of type '"g" | "prerender" | "build" | "docs" | "generate" | "serve" | "telemetry" | "test" | undefined' is not assignable to parameter of type 'TaskCommand'.
Type 'undefined' is not assignable to type 'TaskCommand'.

Argument of type 'Promise<(() => void) | null>' is not assignable to parameter of type 'Promise<() => void>'.

Argument of type 'null' is not assignable to parameter of type 'BuildResultsComponentGraph'.

Argument of type 'DevServerConfig | undefined' is not assignable to parameter of type 'StencilDevServerConfig'.
Type 'undefined' is not assignable to type 'StencilDevServerConfig'.

Argument of type 'Promise<(() => void) | null>' is not assignable to parameter of type 'Promise<() => void>'.
Type '(() => void) | null' is not assignable to type '() => void'.
Type 'null' is not assignable to type '() => void'.

Argument of type 'number | undefined' is not assignable to parameter of type 'number'.
Type 'undefined' is not assignable to type 'number'.

Argument of type 'string' is not assignable to parameter of type 'never'.

Argument of type 'ComponentRuntimeHostListener[] | undefined' is not assignable to parameter of type 'ComponentRuntimeHostListener[]'.
Type 'undefined' is not assignable to type 'ComponentRuntimeHostListener[]'.

Argument of type 'HTMLScriptElement | null | undefined' is not assignable to parameter of type 'HTMLScriptElement'.
Type 'undefined' is not assignable to type 'HTMLScriptElement'.

Argument of type 'string | null' is not assignable to parameter of type 'string'.
Type 'null' is not assignable to type 'string'.

Argument of type 'Diagnostic[] | undefined' is not assignable to parameter of type 'readonly Diagnostic[]'.
Type 'undefined' is not assignable to type 'readonly Diagnostic[]'.

Argument of type 'CompilerSystem | undefined' is not assignable to parameter of type 'CompilerSystem'.
Type 'undefined' is not assignable to type 'CompilerSystem'.

Argument of type 'boolean | undefined' is not assignable to parameter of type 'boolean'.

Argument of type 'BuildConditionals | undefined' is not assignable to parameter of type 'BuildConditionals'.
Type 'undefined' is not assignable to type 'BuildConditionals'.

Argument of type 'Diagnostic[] | undefined' is not assignable to parameter of type 'Diagnostic[]'.
Type 'undefined' is not assignable to type 'Diagnostic[]'.

Argument of type 'WorkerMeta | undefined' is not assignable to parameter of type 'WorkerMeta'.
Type 'undefined' is not assignable to type 'WorkerMeta'.

Argument of type 'CopyTask[] | undefined' is not assignable to parameter of type 'boolean | CopyTask[]'.

Argument of type '{ type: "copy"; dir: string | undefined; copy: d.CopyTask[]; }' is not assignable to parameter of type 'OutputTargetCopy | OutputTargetDistCustomElementsBundle'.
Types of property 'dir' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'CopyTask[] | undefined' is not assignable to parameter of type 'boolean | CopyTask[]'.
Type 'undefined' is not assignable to type 'boolean | CopyTask[]'.

Argument of type '{ type: "copy"; dir: string | undefined; copy: CopyTask[]; }' is not assignable to parameter of type 'OutputTargetCopy | OutputTargetDistCustomElements | OutputTargetDistTypes'.
Types of property 'dir' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'OutputTargetWww' is not assignable to parameter of type 'never'.

Argument of type 'string | null | undefined' is not assignable to parameter of type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'Set<string | null>' is not assignable to parameter of type 'Set'.
Type 'string | null' is not assignable to type 'string'.
Type 'null' is not assignable to type 'string'.

Argument of type 'Set<string | null>' is not assignable to parameter of type 'Set'.

Argument of type 'RollupConfig | undefined' is not assignable to parameter of type 'RollupConfig'.
Type 'undefined' is not assignable to type 'RollupConfig'.

Argument of type '(string[] | undefined)[]' is not assignable to parameter of type 'string[][]'.
Type 'string[] | undefined' is not assignable to type 'string[]'.
Type 'undefined' is not assignable to type 'string[]'.

Argument of type 'ComponentCompilerMeta | undefined' is not assignable to parameter of type 'ComponentCompilerMeta'.
Type 'undefined' is not assignable to type 'ComponentCompilerMeta'.

Argument of type 'SourceTarget | undefined' is not assignable to parameter of type 'SourceTarget'.
Type 'undefined' is not assignable to type 'SourceTarget'.

Argument of type 'boolean | undefined' is not assignable to parameter of type 'boolean'.
Type 'undefined' is not assignable to type 'boolean'.

Argument of type '(string | undefined)[]' is not assignable to parameter of type 'string[]'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type '(string | undefined)[]' is not assignable to parameter of type 'string[]'.

Argument of type 'RollupSourceMap | undefined' is not assignable to parameter of type 'SourceMap'.
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Argument of type 'EntryModule | undefined' is not assignable to parameter of type 'EntryModule'.
Type 'undefined' is not assignable to type 'EntryModule'.

Argument of type '(Module | undefined)[]' is not assignable to parameter of type 'Module[]'.
Type 'Module | undefined' is not assignable to type 'Module'.
Type 'undefined' is not assignable to type 'Module'.

Argument of type 'Document | null' is not assignable to parameter of type 'Document'.
Type 'null' is not assignable to type 'Document'.

Argument of type 'Document | null' is not assignable to parameter of type 'Node | MockNode'.
Type 'null' is not assignable to type 'Node | MockNode'.

Argument of type 'HydrateAnchorElement' is not assignable to parameter of type '{ [attrName: string]: string; }'.
'string' index signatures are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'URL | null' is not assignable to parameter of type 'URL'.
Type 'null' is not assignable to type 'URL'.

Argument of type 'string | undefined' is not assignable to parameter of type 'string | URL'.

Argument of type 'SitemapXmpResults | null' is not assignable to parameter of type 'SitemapXmpResults'.
Type 'null' is not assignable to type 'SitemapXmpResults'.

Argument of type 'Map<string, string[]> | undefined' is not assignable to parameter of type 'Map<string, string[]>'.
Type 'undefined' is not assignable to type 'Map<string, string[]>'.

Argument of type 'undefined' is not assignable to parameter of type 'string'.

Argument of type 'ServiceWorkerConfig | undefined' is not assignable to parameter of type 'ServiceWorkerConfig'.
Type 'undefined' is not assignable to type 'ServiceWorkerConfig'.

Argument of type 'string | undefined' is not assignable to parameter of type 'string | URL'.
Type 'undefined' is not assignable to type 'string | URL'.

Argument of type 'CssNode[] | null | undefined' is not assignable to parameter of type 'void | CssNode[]'.

Argument of type 'CssNode[] | null | undefined' is not assignable to parameter of type 'void | CssNode[]'.
Type 'null' is not assignable to type 'void | CssNode[]'.

Argument of type 'null' is not assignable to parameter of type 'string'.

Argument of type 'CompilerSystemCreateDirectoryOptions | undefined' is not assignable to parameter of type 'CompilerSystemCreateDirectoryOptions'.
Type 'undefined' is not assignable to type 'CompilerSystemCreateDirectoryOptions'.

Argument of type 'null' is not assignable to parameter of type 'CompilerFileWatcherEvent'.

Argument of type 'null' is not assignable to parameter of type 'InMemoryFileSystem'.

Argument of type 'undefined' is not assignable to parameter of type 'TypeChecker'.

Argument of type 'CollectionBundleManifest[] | undefined' is not assignable to parameter of type 'any[]'.
Type 'undefined' is not assignable to type 'any[]'.

Argument of type 'Module | undefined' is not assignable to parameter of type 'Module'.
Type 'undefined' is not assignable to type 'Module'.

Argument of type 'NodeArray | undefined' is not assignable to parameter of type 'NodeArray | HeritageClause[]'.
Type 'undefined' is not assignable to type 'NodeArray | HeritageClause[]'.

Argument of type 'Block | undefined' is not assignable to parameter of type 'Block'.
Type 'undefined' is not assignable to type 'Block'.

Argument of type 'undefined' is not assignable to parameter of type 'readonly ParameterDeclaration[]'.

Argument of type 'Expression | undefined' is not assignable to parameter of type 'Expression'.
Type 'undefined' is not assignable to type 'Expression'.

Argument of type 'Symbol | undefined' is not assignable to parameter of type 'Symbol'.
Type 'undefined' is not assignable to type 'Symbol'.

Argument of type 'string | false' is not assignable to parameter of type 'string'.
Type 'boolean' is not assignable to type 'string'.

Argument of type 'TypeNode | undefined' is not assignable to parameter of type 'Node'.
Type 'undefined' is not assignable to type 'Node'.

Argument of type '(PropertyAssignment | null)[]' is not assignable to parameter of type 'readonly ObjectLiteralElementLike[]'.
Type 'PropertyAssignment | null' is not assignable to type 'ObjectLiteralElementLike'.
Type 'null' is not assignable to type 'ObjectLiteralElementLike'.

Argument of type 'Signature | undefined' is not assignable to parameter of type 'Signature'.
Type 'undefined' is not assignable to type 'Signature'.

Argument of type '(PropertyAssignment | null)[]' is not assignable to parameter of type 'readonly ObjectLiteralElementLike[]'.

Argument of type 'Identifier | undefined' is not assignable to parameter of type 'Node'.
Type 'undefined' is not assignable to type 'Node'.

Argument of type 'undefined' is not assignable to parameter of type 'readonly ClassElement[]'.

Argument of type 'null' is not assignable to parameter of type 'Config | undefined'.

Argument of type 'Config | undefined' is not assignable to parameter of type 'Config'.
Type 'undefined' is not assignable to type 'Config'.

Argument of type 'null' is not assignable to parameter of type 'CollectionCompilerMeta'.

Argument of type 'PropertyName | undefined' is not assignable to parameter of type 'PropertyName'.
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Argument of type 'NamedExportBindings | undefined' is not assignable to parameter of type 'Node'.
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Argument of type 'Declaration | undefined' is not assignable to parameter of type 'Node'.
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Argument of type 'Identifier | undefined' is not assignable to parameter of type 'string | BindingName'.
Type 'undefined' is not assignable to type 'string | BindingName'.

Argument of type 'ScriptTarget | undefined' is not assignable to parameter of type 'ScriptTarget'.
Type 'undefined' is not assignable to type 'ScriptTarget'.

Argument of type 'Diagnostic' is not assignable to parameter of type 'DiagnosticWithLocation'.
Types of property 'file' are incompatible.
Type 'SourceFile | undefined' is not assignable to type 'SourceFile'.
Type 'undefined' is not assignable to type 'SourceFile'.

Argument of type '(...pathSegments: string[]) => string | undefined' is not assignable to parameter of type '(...args: string[]) => string'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'OpenInEditorCallback | undefined' is not assignable to parameter of type 'OpenInEditorCallback'.
Type 'undefined' is not assignable to type 'OpenInEditorCallback'.

Argument of type 'CompilerWatcher | undefined' is not assignable to parameter of type 'CompilerWatcher'.
Type 'undefined' is not assignable to type 'CompilerWatcher'.

Argument of type '{ editor: string | undefined; }' is not assignable to parameter of type 'OpenInEditorOptions'.
Types of property 'editor' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Argument of type 'string | undefined' is not assignable to parameter of type 'PathLike'.
Type 'undefined' is not assignable to type 'PathLike'.

Argument of type 'DevServerConfig | undefined' is not assignable to parameter of type 'DevServerConfig'.
Type 'undefined' is not assignable to type 'DevServerConfig'.

Argument of type 'CompilerBuildResults | undefined' is not assignable to parameter of type 'CompilerBuildResults'.
Type 'undefined' is not assignable to type 'CompilerBuildResults'.

Argument of type 'Window | undefined' is not assignable to parameter of type 'Window'.
Type 'undefined' is not assignable to type 'Window'.

Argument of type 'SerializeDocumentOptions | undefined' is not assignable to parameter of type 'HydrateDocumentOptions'.
Type 'undefined' is not assignable to type 'HydrateDocumentOptions'.

Argument of type 'HydrateDocumentOptions | undefined' is not assignable to parameter of type 'HydrateDocumentOptions'.
Type 'undefined' is not assignable to type 'HydrateDocumentOptions'.

Argument of type 'MockNode | null' is not assignable to parameter of type 'MockNode'.
Type 'null' is not assignable to type 'MockNode'.

Argument of type 'ShadowRoot | null' is not assignable to parameter of type 'Node'.
Type 'null' is not assignable to type 'Node'.

Argument of type 'null' is not assignable to parameter of type 'string | Node'.

Argument of type 'null' is not assignable to parameter of type 'string | boolean | undefined'.

Argument of type '(Window & typeof globalThis) | null' is not assignable to parameter of type 'Window'.
Type 'null' is not assignable to type 'Window'.

Argument of type 'string | null | undefined' is not assignable to parameter of type 'string | undefined'.

Argument of type 'HostRef | undefined' is not assignable to parameter of type 'HostRef'.
Type 'undefined' is not assignable to type 'HostRef'.

Argument of type 'this' is not assignable to parameter of type 'HostElement'.
Type 'HostElement' is not assignable to type 'import("/home/runner/work/stencil/stencil/src/declarations/stencil-private").HostElement'.
The types returned by 'componentOnReady()' are incompatible between these types.
Type 'Promise | undefined' is not assignable to type 'Promise'.
Type 'undefined' is not assignable to type 'Promise'.

Argument of type 'this' is not assignable to parameter of type 'HostElement'.

Argument of type 'string | null' is not assignable to parameter of type 'string | undefined'.

Argument of type 'PropertyDescriptor | undefined' is not assignable to parameter of type 'PropertyDescriptor & ThisType'.
Type 'undefined' is not assignable to type 'PropertyDescriptor & ThisType'.
Type 'undefined' is not assignable to type 'PropertyDescriptor'.

Argument of type 'HTMLElement | undefined' is not assignable to parameter of type 'HTMLElement'.
Type 'undefined' is not assignable to type 'HTMLElement'.

Argument of type 'HostElement | undefined' is not assignable to parameter of type 'HostElement'.
Type 'undefined' is not assignable to type 'HostElement'.

Argument of type 'HostElement | undefined' is not assignable to parameter of type 'EventTarget'.
Type 'undefined' is not assignable to type 'EventTarget'.

Argument of type 'HostElement | undefined' is not assignable to parameter of type 'Element'.
Type 'undefined' is not assignable to type 'Element'.

Argument of type 'VNode[] | undefined' is not assignable to parameter of type 'VNode[]'.
Type 'undefined' is not assignable to type 'VNode[]'.

Argument of type 'null | undefined' is not assignable to parameter of type 'ChildType'.
Type 'undefined' is not assignable to type 'ChildType'.

Argument of type 'VNode | null' is not assignable to parameter of type 'ChildType'.
Type 'null' is not assignable to type 'ChildType'.

Argument of type 'VNode | undefined' is not assignable to parameter of type 'ChildType'.
Type 'undefined' is not assignable to type 'ChildType'.

Argument of type 'VNode | null | undefined' is not assignable to parameter of type 'ChildType'.
Type 'undefined' is not assignable to type 'ChildType'.

Argument of type 'null | undefined' is not assignable to parameter of type 'ChildType'.

Argument of type 'RenderNode | undefined' is not assignable to parameter of type 'Node | null'.
Type 'undefined' is not assignable to type 'Node | null'.

Argument of type 'VNode | undefined' is not assignable to parameter of type 'VNode'.
Type 'undefined' is not assignable to type 'VNode'.

Argument of type 'null' is not assignable to parameter of type 'VNode'.

Argument of type 'RenderNode | undefined' is not assignable to parameter of type 'Node'.
Type 'undefined' is not assignable to type 'Node'.

Argument of type 'null' is not assignable to parameter of type 'RenderNode'.

Argument of type 'ScreenshotDiff | undefined' is not assignable to parameter of type 'ScreenshotDiff'.
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Argument of type 'string | undefined' is not assignable to parameter of type 'PathLike'.

Argument of type 'string | undefined' is not assignable to parameter of type 'string | SemVer'.
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Argument of type 'string | undefined' is not assignable to parameter of type 'string | SemVer'.

Argument of type 'null' is not assignable to parameter of type 'number | undefined'.

Argument of type 'null' is not assignable to parameter of type 'number | PromiseLike'.

Argument of type 'CompilerWorkerTask | undefined' is not assignable to parameter of type 'CompilerWorkerTask'.
Type 'undefined' is not assignable to type 'CompilerWorkerTask'.

Argument of type 'null' is not assignable to parameter of type 'CompilerWorkerTask'.

Argument of type 'TestingConfig | undefined' is not assignable to parameter of type 'TestingConfig'.
Type 'undefined' is not assignable to type 'TestingConfig'.

Argument of type 'undefined' is not assignable to parameter of type 'ErrorHandler'.

Argument of type 'string | undefined' is not assignable to parameter of type 'MockRequestInfo'.
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Argument of type 'string | undefined' is not assignable to parameter of type 'MockRequestInfo'.

Argument of type 'MockResponse | undefined' is not assignable to parameter of type 'MockResponse'.
Type 'undefined' is not assignable to type 'MockResponse'.

Argument of type 'this' is not assignable to parameter of type 'E2EElementInternal'.
Type 'E2EElement' is not assignable to type 'E2EElementInternal'.
Types of property 'find' are incompatible.
Type '(selector: string) => Promise<E2EElement | null>' is not assignable to type '(selector: FindSelector) => Promise'.

Argument of type 'string | null | undefined' is not assignable to parameter of type 'SerializableOrJSHandle'.
Type 'undefined' is not assignable to type 'SerializableOrJSHandle'.

Argument of type 'this' is not assignable to parameter of type 'E2EElementInternal'.

Argument of type 'ElementHandle | null' is not assignable to parameter of type 'ElementHandle'.
Type 'null' is not assignable to type 'ElementHandle'.

Argument of type '{ viewport: EmulateViewport | undefined; userAgent: string | undefined; }' is not assignable to parameter of type '{ viewport: Viewport; userAgent: string; }'.
Types of property 'viewport' are incompatible.
Type 'EmulateViewport | undefined' is not assignable to type 'Viewport'.
Type 'undefined' is not assignable to type 'Viewport'.

Argument of type 'AnyHTMLElement | undefined' is not assignable to parameter of type 'RuntimeRef'.
Type 'undefined' is not assignable to type 'RuntimeRef'.

Argument of type 'null' is not assignable to parameter of type 'SourceMap | undefined'.
TS2322 555
Error messages Type 'null' is not assignable to type 'TaskCommand | undefined'.

Type 'null' is not assignable to type 'string[] | undefined'.

Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type 'null' is not assignable to type 'DevServerConfig | undefined'.

Type 'null' is not assignable to type 'DevServer'.

Type 'undefined' is not assignable to type 'number'.

Type 'string[] | undefined' is not assignable to type 'string[]'.
Type 'undefined' is not assignable to type 'string[]'.

Type 'TaskCommand | undefined' is not assignable to type 'TaskCommand'.
Type 'undefined' is not assignable to type 'TaskCommand'.

Type 'PackageJsonData | null' is not assignable to type 'PackageJsonData'.
Type 'null' is not assignable to type 'PackageJsonData'.

Type 'undefined' is not assignable to type 'ComponentConstructor | Promise'.

Type 'HTMLElement | null' is not assignable to type 'HTMLElement'.
Type 'null' is not assignable to type 'HTMLElement'.

Type 'null' is not assignable to type 'RollupResult[]'.

Type '({ type: "chunk"; fileName: string; map: SourceMap | undefined; code: string; moduleFormat: ModuleFormat | undefined; entryKey: string; imports: string[]; isEntry: boolean; ... 4 more ...; content?: undefined; } | { ...; })[]' is not assignable to type 'RollupResult[]'.
Type '{ type: "chunk"; fileName: string; map: SourceMap | undefined; code: string; moduleFormat: ModuleFormat | undefined; entryKey: string; imports: string[]; isEntry: boolean; ... 4 more ...; content?: undefined; } | { ...; }' is not assignable to type 'RollupResult'.
Type '{ type: "chunk"; fileName: string; map: SourceMap | undefined; code: string; moduleFormat: ModuleFormat | undefined; entryKey: string; imports: string[]; isEntry: boolean; ... 4 more ...; content?: undefined; }' is not assignable to type 'RollupResult'.
Type '{ type: "chunk"; fileName: string; map: SourceMap | undefined; code: string; moduleFormat: ModuleFormat | undefined; entryKey: string; imports: string[]; isEntry: boolean; ... 4 more ...; content?: undefined; }' is not assignable to type 'RollupChunkResult'.
Types of property 'moduleFormat' are incompatible.
Type 'ModuleFormat | undefined' is not assignable to type 'ModuleFormat'.
Type 'undefined' is not assignable to type 'ModuleFormat'.

Type 'null' is not assignable to type 'CompilerBuildResults'.

Type 'undefined' is not assignable to type 'string'.

Type 'null' is not assignable to type 'string'.

Type 'undefined' is not assignable to type 'Document'.

Type 'null' is not assignable to type 'Promise'.

Type 'null' is not assignable to type 'LoggerTimeSpan'.

Type 'boolean | undefined' is not assignable to type 'boolean'.

Type 'number | undefined' is not assignable to type 'number'.
Type 'undefined' is not assignable to type 'number'.

Type 'boolean | "prod" | undefined' is not assignable to type 'boolean | "prod"'.
Type 'undefined' is not assignable to type 'boolean | "prod"'.

Type 'BuildResultsComponentGraph | undefined' is not assignable to type 'BuildResultsComponentGraph'.
Type 'undefined' is not assignable to type 'BuildResultsComponentGraph'.

Type 'RollupResults | undefined' is not assignable to type 'RollupResults'.
Type 'undefined' is not assignable to type 'RollupResults'.

Type '{ name: string | undefined; source: string; tags: any[]; }[]' is not assignable to type '{ name: string; source: string; tags: string[]; }[]'.
Type '{ name: string | undefined; source: string; tags: any[]; }' is not assignable to type '{ name: string; source: string; tags: string[]; }'.
Types of property 'name' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type 'null' is not assignable to type 'CompilerWorkerContext'.

Type 'null' is not assignable to type 'WatchOfConfigFile'.

Type 'null' is not assignable to type '{ program: WatchOfConfigFile; rebuild: () => void; }'.

Type 'string | null' is not assignable to type 'string'.
Type 'null' is not assignable to type 'string'.

Type 'ComponentCompilerMeta | undefined' is not assignable to type 'ComponentCompilerMeta'.
Type 'undefined' is not assignable to type 'ComponentCompilerMeta'.

Type 'null' is not assignable to type 'string | undefined'.

Type '{ code: string; exports: string[]; workerMsgId: string; dependencies: string[]; } | null' is not assignable to type 'WorkerMeta | undefined'.
Type 'null' is not assignable to type 'WorkerMeta | undefined'.

Type 'WorkerMeta | undefined' is not assignable to type 'WorkerMeta'.
Type 'undefined' is not assignable to type 'WorkerMeta'.

Type 'CompilerSystem | undefined' is not assignable to type 'CompilerSystem'.
Type 'undefined' is not assignable to type 'CompilerSystem'.

Type 'Logger | undefined' is not assignable to type 'Logger'.
Type 'undefined' is not assignable to type 'Logger'.

Type 'import("/home/runner/work/stencil/stencil/src/compiler/cache").Cache' is not assignable to type 'import("/home/runner/work/stencil/stencil/src/declarations/stencil-private").Cache'.
The types returned by 'get(...)' are incompatible between these types.
Type 'Promise<string | null>' is not assignable to type 'Promise'.

Type 'null' is not assignable to type 'UnvalidatedConfig'.
Type 'null' is not assignable to type 'Record<string, any>'.

Type 'null' is not assignable to type 'string[]'.

Type 'null' is not assignable to type 'UnvalidatedConfig'.

Type 'null' is not assignable to type '{ config?: UnvalidatedConfig | undefined; }'.

Type '{ dir: string; buildDir: string; collectionDir: string | null; typesDir: string; esmLoaderPath: string; copy: d.CopyTask[]; polyfills: boolean | undefined; empty: boolean; type: "dist"; }' is not assignable to type 'Required'.
Types of property 'polyfills' are incompatible.
Type 'boolean | undefined' is not assignable to type 'boolean'.

Type 'string' is not assignable to type 'never'.

Type 'string | undefined' is not assignable to type 'never'.
Type 'undefined' is not assignable to type 'never'.

Type 'boolean | undefined' is not assignable to type 'never'.
Type 'undefined' is not assignable to type 'never'.

Type 'boolean' is not assignable to type 'never'.

Type 'CopyTask[]' is not assignable to type 'never'.

Type 'null' is not assignable to type 'number | undefined'.

Type 'null' is not assignable to type 'HistoryApiFallback | undefined'.

Type 'null' is not assignable to type 'CopyTask[] | undefined'.

Type '{ dirPath: string; filePath: string; fileName: string; readmePath: string; usagesDir: string; tag: string; readme: string | undefined; usage: JsonDocsUsage; docs: string; docsTags: CompilerJsDocTagInfo[]; ... 11 more ...; listeners: JsonDocsListener[]; }[]' is not assignable to type 'JsonDocsComponent[]'.
Type '{ dirPath: string; filePath: string; fileName: string; readmePath: string; usagesDir: string; tag: string; readme: string | undefined; usage: d.JsonDocsUsage; docs: string; docsTags: d.CompilerJsDocTagInfo[]; ... 11 more ...; listeners: d.JsonDocsListener[]; }' is not assignable to type 'JsonDocsComponent'.
Types of property 'readme' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type '{ name: string; type: string; mutable: boolean; attr: string | undefined; reflectToAttr: boolean; docs: string; docsTags: CompilerJsDocTagInfo[]; default: string | undefined; deprecation: string | undefined; values: JsonDocsValue[]; optional: boolean; required: boolean; }[]' is not assignable to type 'JsonDocsProp[]'.
Type '{ name: string; type: string; mutable: boolean; attr: string | undefined; reflectToAttr: boolean; docs: string; docsTags: d.CompilerJsDocTagInfo[]; default: string | undefined; deprecation: string | undefined; values: d.JsonDocsValue[]; optional: boolean; required: boolean; }' is not assignable to type 'JsonDocsProp'.
Types of property 'default' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type '{ name: string; type: string; mutable: false; attr: string; reflectToAttr: false; docs: string; docsTags: never[]; default: undefined; deprecation: undefined; values: JsonDocsValue[]; optional: true; required: false; }[]' is not assignable to type 'JsonDocsProp[]'.
Type '{ name: string; type: string; mutable: false; attr: string; reflectToAttr: false; docs: string; docsTags: never[]; default: undefined; deprecation: undefined; values: d.JsonDocsValue[]; optional: true; required: false; }' is not assignable to type 'JsonDocsProp'.
Types of property 'default' are incompatible.
Type 'undefined' is not assignable to type 'string'.

Type '(ComponentCompilerMeta | undefined)[]' is not assignable to type 'ComponentCompilerMeta[]'.
Type 'ComponentCompilerMeta | undefined' is not assignable to type 'ComponentCompilerMeta'.
Type 'undefined' is not assignable to type 'ComponentCompilerMeta'.

Type '(ComponentCompilerMeta | undefined)[][]' is not assignable to type 'readonly ComponentCompilerMeta[][]'.
Type '(ComponentCompilerMeta | undefined)[]' is not assignable to type 'ComponentCompilerMeta[]'.

Type 'null' is not assignable to type 'SourceMap | undefined'.

Type '{ name: string | undefined; tags: string[]; }[]' is not assignable to type 'CollectionDependencyData[]'.
Type '{ name: string | undefined; tags: string[]; }' is not assignable to type 'CollectionDependencyData'.
Types of property 'name' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type 'string | undefined' is not assignable to type 'string | number'.
Type 'undefined' is not assignable to type 'string | number'.

Type 'SourceMap | undefined' is not assignable to type 'SourceMap'.
Type 'undefined' is not assignable to type 'SourceMap'.

Type 'string | null' is not assignable to type 'string | undefined'.
Type 'null' is not assignable to type 'string | undefined'.

Type 'null' is not assignable to type 'Function'.

Type 'null' is not assignable to type 'Map<string, string[]>'.

Type 'null' is not assignable to type 'PrerenderConfig'.

Type 'null' is not assignable to type 'Set'.

Type 'null' is not assignable to type 'HydrateAnchorElement[]'.

Type 'null' is not assignable to type '(prerenderRequest: PrerenderUrlRequest) => Promise'.

Type 'RegExpExecArray | null' is not assignable to type 'RegExpExecArray'.
Type 'null' is not assignable to type 'RegExpExecArray'.

Type 'CssNode | null' is not assignable to type 'void | CssNode'.
Type 'null' is not assignable to type 'void | CssNode'.

Type 'CssNode | null' is not assignable to type 'CssNode'.
Type 'null' is not assignable to type 'CssNode'.

Type 'CssNode | null' is not assignable to type 'void | CssNode'.

Type 'null' is not assignable to type '() => string'.

Type 'null' is not assignable to type 'number'.

Type 'null' is not assignable to type 'boolean'.

Type 'null' is not assignable to type 'boolean | undefined'.

Type 'FsItem | undefined' is not assignable to type 'FsItem'.
Type 'undefined' is not assignable to type 'FsItem'.

Type 'null' is not assignable to type 'CompilerFileWatcherCallback[]'.

Type '(key: string) => string | undefined' is not assignable to type '(key: string) => string'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type '(p: string) => Promise<string | undefined>' is not assignable to type '{ (p: string): Promise; (p: string, encoding: "utf8"): Promise; (p: string, encoding: "binary"): Promise; }'.
Type 'Promise<string | undefined>' is not assignable to type 'Promise'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type '(p: string) => string | undefined' is not assignable to type '(p: string, encoding?: string | undefined) => string'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type '((maxConcurrentWorkers: number) => WorkerMainController) | null' is not assignable to type '((maxConcurrentWorkers: number) => WorkerMainController) | undefined'.
Type 'null' is not assignable to type '((maxConcurrentWorkers: number) => WorkerMainController) | undefined'.

Type 'null' is not assignable to type 'ResolvedModuleWithFailedLookupLocations'.

Type 'null' is not assignable to type 'Worker'.

Type 'CollectionCompilerMeta | undefined' is not assignable to type 'CollectionCompilerMeta'.
Type 'undefined' is not assignable to type 'CollectionCompilerMeta'.

Type 'null' is not assignable to type 'ComponentCompilerStaticEvent'.

Type 'null' is not assignable to type 'PropertyAssignment'.

Type 'boolean | null' is not assignable to type 'boolean'.
Type 'null' is not assignable to type 'boolean'.

Type 'undefined' is not assignable to type 'ComponentCompilerVirtualProperty'.

Type '{ name: string; method: string; bubbles: boolean; cancelable: boolean; composed: boolean; docs: CompilerJsDoc; complexType: ComponentCompilerEventComplexType; internal: boolean | undefined; }[]' is not assignable to type 'ComponentCompilerEvent[]'.
Type '{ name: string; method: string; bubbles: boolean; cancelable: boolean; composed: boolean; docs: d.CompilerJsDoc; complexType: d.ComponentCompilerEventComplexType; internal: boolean | undefined; }' is not assignable to type 'ComponentCompilerEvent'.
Types of property 'internal' are incompatible.
Type 'boolean | undefined' is not assignable to type 'boolean'.

Type '{ name: string; docs: CompilerJsDoc; complexType: ComponentCompilerMethodComplexType; internal: boolean | undefined; }[]' is not assignable to type 'ComponentCompilerMethod[]'.
Type '{ name: string; docs: d.CompilerJsDoc; complexType: d.ComponentCompilerMethodComplexType; internal: boolean | undefined; }' is not assignable to type 'ComponentCompilerMethod'.
Types of property 'internal' are incompatible.
Type 'boolean | undefined' is not assignable to type 'boolean'.

Type '{ name: string; type: ComponentCompilerPropertyType; attribute: string | undefined; reflect: boolean; mutable: boolean; required: boolean; optional: boolean; defaultValue: string | undefined; complexType: ComponentCompilerPropertyComplexType; docs: CompilerJsDoc; internal: boolean | undefined; }[]' is not assignable to type 'ComponentCompilerProperty[]'.
Type '{ name: string; type: d.ComponentCompilerPropertyType; attribute: string | undefined; reflect: boolean; mutable: boolean; required: boolean; optional: boolean; defaultValue: string | undefined; complexType: d.ComponentCompilerPropertyComplexType; docs: d.CompilerJsDoc; internal: boolean | undefined; }' is not assignable to type 'ComponentCompilerProperty'.
Types of property 'internal' are incompatible.
Type 'boolean | undefined' is not assignable to type 'boolean'.

Type 'null' is not assignable to type 'ImportData'.

Type 'undefined' is not assignable to type '"queryparams" | null'.

Type 'null' is not assignable to type 'WeakSet'.

Type 'null' is not assignable to type 'Module'.

Type 'Module | undefined' is not assignable to type 'Module'.
Type 'undefined' is not assignable to type 'Module'.

Type 'undefined' is not assignable to type 'CompilerJsDoc'.

Type '{ [x: string]: d.TypesMemberNameData[] | undefined; }' is not assignable to type 'TypesImportData'.
'string' index signatures are incompatible.
Type 'TypesMemberNameData[] | undefined' is not assignable to type 'TypesMemberNameData[]'.
Type 'undefined' is not assignable to type 'TypesMemberNameData[]'.

Type 'string | undefined' is not assignable to type 'string | null'.

Type '((data: { file: string; line: number; column: number; }) => void) | null' is not assignable to type 'OpenInEditorCallback | undefined'.
Type 'null' is not assignable to type 'OpenInEditorCallback | undefined'.

Type 'null' is not assignable to type 'WebSocket'.

Type 'null' is not assignable to type 'BuildOnEventRemove'.

Type 'null' is not assignable to type '() => void'.

Type 'null' is not assignable to type '(msg: DevServerMessage) => void'.

Type 'DevServerConfig | undefined' is not assignable to type 'DevServerConfig'.
Type 'undefined' is not assignable to type 'DevServerConfig'.

Type 'null' is not assignable to type '{ open(openId: string): Promise; }'.

Type 'string | null' is not assignable to type 'string | undefined'.

Type 'null' is not assignable to type 'Promise<DevServerEditor[]>'.

Type 'null' is not assignable to type '(req: IncomingMessage, res: ServerResponse, next: () => void) => void'.

Type 'null' is not assignable to type 'URL'.

Type 'null' is not assignable to type 'URLSearchParams'.

Type 'PageReloadStrategy | undefined' is not assignable to type 'PageReloadStrategy'.
Type 'undefined' is not assignable to type 'PageReloadStrategy'.

Type 'null' is not assignable to type 'Server'.

Type 'null' is not assignable to type 'DevWebSocket'.

Type 'null' is not assignable to type 'DevServerContext'.

Type 'DevWebSocket | null' is not assignable to type 'DevWebSocket'.
Type 'null' is not assignable to type 'DevWebSocket'.

Type 'string | undefined' is not assignable to type 'string | null'.
Type 'undefined' is not assignable to type 'string | null'.

Type 'null' is not assignable to type 'ChildProcess'.

Type 'null' is not assignable to type 'HydrateApp'.

Type 'null' is not assignable to type 'ComponentConstructor'.

Type '(this: HostElement) => Promise | undefined' is not assignable to type '() => Promise'.
Type 'Promise | undefined' is not assignable to type 'Promise'.
Type 'undefined' is not assignable to type 'Promise'.

Type 'null' is not assignable to type 'Window & typeof globalThis'.
Type 'null' is not assignable to type 'Window'.

Type 'null' is not assignable to type 'Window & typeof globalThis'.

Type 'null' is not assignable to type 'MockCSSStyleSheet'.

Type 'null' is not assignable to type 'string | boolean'.

Type 'null' is not assignable to type 'Location'.

Type 'null' is not assignable to type 'MockNode'.

Type 'null' is not assignable to type 'MockElement'.

Type 'null' is not assignable to type 'SVGSVGElement'.

Type 'null' is not assignable to type 'SVGElement'.

Type 'null' is not assignable to type 'EventTarget'.

Type 'null' is not assignable to type 'MockEventListener[]'.

Type 'null' is not assignable to type 'MockDocument'.

Type '{ name: string; value: string; namespace: string; prefix: null; }[]' is not assignable to type 'Attribute[]'.
Type '{ name: string; value: string; namespace: string; prefix: null; }' is not assignable to type 'Attribute'.
Types of property 'prefix' are incompatible.
Type 'null' is not assignable to type 'string | undefined'.

Type 'ParentNode | null' is not assignable to type 'Node'.
Type 'null' is not assignable to type 'Node'.

Type 'null' is not assignable to type 'Document'.

Type 'string | null | undefined' is not assignable to type 'string | undefined'.

Type 'never[] | null' is not assignable to type 'RenderNode[]'.
Type 'null' is not assignable to type 'RenderNode[]'.

Type 'null' is not assignable to type 'VNode[]'.

Type 'null' is not assignable to type 'string | number | undefined'.

Type 'null' is not assignable to type 'string | number | Function'.

Type 'RenderNode | null' is not assignable to type 'RenderNode'.
Type 'null' is not assignable to type 'RenderNode'.

Type 'HTMLElement | null' is not assignable to type 'EventTarget'.
Type 'null' is not assignable to type 'EventTarget'.

Type 'string | null | undefined' is not assignable to type 'string | undefined'.
Type 'null' is not assignable to type 'string | undefined'.

Type 'null' is not assignable to type 'Set | undefined'.

Type 'null' is not assignable to type '[string, any][] | undefined'.

Type 'VNode[] | undefined' is not assignable to type 'VNode[]'.
Type 'undefined' is not assignable to type 'VNode[]'.

Type '(props: {}, children: VNode[], utils: FunctionalUtilities) => null' is not assignable to type 'FunctionalComponent<{}>'.
Type 'null' is not assignable to type 'VNode | VNode[]'.

Type '() => null' is not assignable to type 'FunctionalComponent<{}>'.
Type 'null' is not assignable to type 'VNode | VNode[]'.

Type 'null' is not assignable to type 'VNode'.

Type 'undefined' is not assignable to type 'VNode'.

Type 'RenderNode | undefined' is not assignable to type 'RenderNode'.
Type 'undefined' is not assignable to type 'RenderNode'.

Type 'RelocateNodeData | undefined' is not assignable to type 'RelocateNodeData'.
Type 'undefined' is not assignable to type 'RelocateNodeData'.

Type 'ChildNode | null' is not assignable to type 'Node'.
Type 'null' is not assignable to type 'Node'.

Type 'null' is not assignable to type 'ScreenshotBuild'.

Type 'null' is not assignable to type 'ScreenshotCache'.

Type 'null' is not assignable to type 'Buffer'.

Type 'null' is not assignable to type 'Screenshot'.

Type '(() => void) | undefined' is not assignable to type '() => any'.
Type 'undefined' is not assignable to type '() => any'.

Type '() => null' is not assignable to type '(opts: { rootDir: string; moduleId: string; path: string; }) => string'.
Type 'null' is not assignable to type 'string'.

Type '() => null' is not assignable to type '(opts: { moduleId: string; path?: string | undefined; version?: string | undefined; }) => string'.
Type 'null' is not assignable to type 'string'.

Type '() => string | undefined' is not assignable to type '() => string'.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type 'number | null' is not assignable to type 'number'.
Type 'null' is not assignable to type 'number'.

Type 'any[] | undefined' is not assignable to type 'any[]'.
Type 'undefined' is not assignable to type 'any[]'.

Type 'CompilerOptions | null' is not assignable to type 'CompilerOptions'.
Type 'null' is not assignable to type 'CompilerOptions'.

Type 'null' is not assignable to type 'ConfigBundle[] | undefined'.

Type 'null' is not assignable to type 'OutputTarget[] | undefined'.

Type 'null' is not assignable to type 'TestingConfig | undefined'.

Type 'null' is not assignable to type 'Cache'.

Type 'null' is not assignable to type 'BuildEvents'.

Type 'null' is not assignable to type 'InMemoryFileSystem'.

Type 'HostRef | undefined' is not assignable to type 'HostRef'.
Type 'undefined' is not assignable to type 'HostRef'.

Type 'Function | undefined' is not assignable to type 'Function'.
Type 'undefined' is not assignable to type 'Function'.

Type 'RafCallback | undefined' is not assignable to type 'Function'.
Type 'undefined' is not assignable to type 'Function'.

Type 'QueuedLoadModule | undefined' is not assignable to type 'QueuedLoadModule'.
Type 'undefined' is not assignable to type 'QueuedLoadModule'.

Type 'null' is not assignable to type 'ElementHandle'.

Type 'null' is not assignable to type 'E2EPageInternal'.

Type 'ElementHandle | null' is not assignable to type 'ElementHandle'.
Type 'null' is not assignable to type 'ElementHandle'.

Type 'null' is not assignable to type 'Promise<JSHandle>'.

Type '(a?: any, b?: any) => Promise<ScreenshotDiff | undefined>' is not assignable to type '{ (): Promise; (description: string): Promise; (opts: ScreenshotOptions): Promise<...>; (description: string, opts: ScreenshotOptions): Promise<...>; }'.
Type 'Promise<ScreenshotDiff | undefined>' is not assignable to type 'Promise'.
Type 'ScreenshotDiff | undefined' is not assignable to type 'ScreenshotDiff'.
Type 'undefined' is not assignable to type 'ScreenshotDiff'.

Type 'null' is not assignable to type 'Function | undefined'.

Type 'null' is not assignable to type 'CompilerWatcher'.

Type 'null' is not assignable to type 'Promise'.

Type 'Browser | null' is not assignable to type 'Browser'.
Type 'null' is not assignable to type 'Browser'.

Type 'null' is not assignable to type 'Config'.

Type 'null' is not assignable to type 'Browser'.

Type 'null' is not assignable to type 'SourceMap'.

Type 'null' is not assignable to type 'PackageJsonData'.

Type 'null' is not assignable to type '{ [moduleId: string]: string; } | undefined'.

Type '{ diagnostic: d.Diagnostic; data: any; filePath: string | undefined; }' is not assignable to type '{ diagnostic: Diagnostic; data: PackageJsonData; filePath: string; }'.
Types of property 'filePath' are incompatible.
Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

Type 'null' is not assignable to type '{ diagnostic: Diagnostic; data: PackageJsonData; filePath: string; }'.
TS2531 198
Error messages Object is possibly 'null'.
TS2454 48
Error messages Variable 'pkgJsonData' is used before being assigned.

Variable 'cmp' is used before being assigned.

Variable 'minifyOpts' is used before being assigned.

Variable 'workerCtrl' is used before being assigned.

Variable 'timespan' is used before being assigned.

Variable 'content' is used before being assigned.

Variable 'compilerExe' is used before being assigned.

Variable 'outputText' is used before being assigned.

Variable 'distDtsFilePath' is used before being assigned.

Variable 'importResolvedFile' is used before being assigned.

Variable 'win' is used before being assigned.

Variable 'attrName' is used before being assigned.

Variable 'oldValue' is used before being assigned.

Variable 'newValue' is used before being assigned.

Variable 'hostId' is used before being assigned.

Variable 'promise' is used before being assigned.

Variable 'textContent' is used before being assigned.

Variable 'resolve' is used before being assigned.

Variable 'opts' is used before being assigned.
TS2722 43
Error messages Cannot invoke an object which is possibly 'undefined'.
TS2352 21
Error messages Conversion of type 'null' to type 'string' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.

Conversion of type 'null' to type 'CompilerSystem' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.

Conversion of type 'null' to type 'string[]' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.

Conversion of type '{ cmps: never[]; }' to type 'Module' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
Type '{ cmps: never[]; }' is missing the following properties from type 'Module': coreRuntimeApis, collectionName, dtsFilePath, excludeFromCollection, and 27 more.

Conversion of type 'null' to type 'ScreenshotCache' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.

Conversion of type 'null' to type 'Diagnostic' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
TS2769 18
Error messages No overload matches this call.
Overload 1 of 2, '(o: {}): string[]', gave the following error.
Argument of type 'BuildResultsComponentGraph | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.
Overload 2 of 2, '(o: object): string[]', gave the following error.
Argument of type 'BuildResultsComponentGraph | undefined' is not assignable to parameter of type 'object'.
Type 'undefined' is not assignable to type 'object'.

No overload matches this call.
Overload 1 of 4, '(object: {}, method: never): SpyInstance<never, never>', gave the following error.
Argument of type 'Logger | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.
Overload 2 of 4, '(object: {}, method: never): SpyInstance<never, never>', gave the following error.
Argument of type 'Logger | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.

No overload matches this call.
Overload 1 of 4, '(object: {}, method: never): SpyInstance<never, never>', gave the following error.
Argument of type 'CompilerSystem | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.
Overload 2 of 4, '(object: {}, method: never): SpyInstance<never, never>', gave the following error.
Argument of type 'CompilerSystem | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.

No overload matches this call.
Overload 1 of 2, '(type: keyof DocumentEventMap, listener: (this: Document, ev: PointerEvent | MouseEvent | UIEvent | Event | ErrorEvent | ... 13 more ... | WheelEvent) => any, options?: boolean | ... 1 more ... | undefined): void', gave the following error.
Argument of type '"e"' is not assignable to parameter of type 'keyof DocumentEventMap'.
Overload 2 of 2, '(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions | undefined): void', gave the following error.
Argument of type 'null' is not assignable to parameter of type 'EventListenerOrEventListenerObject'.

No overload matches this call.
Overload 1 of 2, '(...items: ConcatArray[]): HostRule[]', gave the following error.
Argument of type 'HostRule[] | undefined' is not assignable to parameter of type 'ConcatArray'.
Type 'undefined' is not assignable to type 'ConcatArray'.
Overload 2 of 2, '(...items: (HostRule | ConcatArray)[]): HostRule[]', gave the following error.
Argument of type 'HostRule[] | undefined' is not assignable to parameter of type 'HostRule | ConcatArray'.
Type 'undefined' is not assignable to type 'HostRule | ConcatArray'.

No overload matches this call.
The last overload gave the following error.
Argument of type 'string | null' is not assignable to parameter of type '(substring: string, ...args: any[]) => string'.
Type 'null' is not assignable to type '(substring: string, ...args: any[]) => string'.

No overload matches this call.
The last overload gave the following error.
Argument of type 'string | null' is not assignable to parameter of type 'string | number | boolean | PseudoBigInt'.
Type 'null' is not assignable to type 'string | number | boolean | PseudoBigInt'.

No overload matches this call.
Overload 1 of 2, '(configFileName: string, optionsToExtend: CompilerOptions | undefined, system: System, createProgram?: CreateProgram | undefined, reportDiagnostic?: DiagnosticReporter | undefined, reportWatchStatus?: WatchStatusReporter | undefined, watchOptionsToExtend?: WatchOptions | undefined, extraFileExtensions?: readonly FileExtensionInfo[] | undefined): WatchCompilerHostOfConfigFile<...>', gave the following error.
Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
Type 'undefined' is not assignable to type 'string'.
Overload 2 of 2, '(rootFiles: string[], options: CompilerOptions, system: System, createProgram?: CreateProgram | undefined, reportDiagnostic?: DiagnosticReporter | undefined, reportWatchStatus?: WatchStatusReporter | undefined, projectReferences?: readonly ProjectReference[] | undefined, watchOptions?: WatchOptions | undefined): WatchCompilerHostOfFilesAndCompilerOptions<...>', gave the following error.
Argument of type 'string | undefined' is not assignable to parameter of type 'string[]'.
Type 'undefined' is not assignable to type 'string[]'.

No overload matches this call.
Overload 1 of 2, '(timeoutId: Timeout): void', gave the following error.
Argument of type 'Timeout | null' is not assignable to parameter of type 'Timeout'.
Type 'null' is not assignable to type 'Timeout'.
Overload 2 of 2, '(handle?: number | undefined): void', gave the following error.
Argument of type 'Timeout | null' is not assignable to parameter of type 'number | undefined'.
Type 'null' is not assignable to type 'number | undefined'.

No overload matches this call.
Overload 1 of 2, '(timeoutId: Timeout): void', gave the following error.
Argument of type 'Timeout | null' is not assignable to parameter of type 'Timeout'.
Type 'null' is not assignable to type 'Timeout'.
Overload 2 of 2, '(handle?: number | undefined): void', gave the following error.
Argument of type 'Timeout | null' is not assignable to parameter of type 'number | undefined'.

No overload matches this call.
Overload 1 of 3, '(p: string, encoding: "utf8"): Promise', gave the following error.
Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
Type 'undefined' is not assignable to type 'string'.
Overload 2 of 3, '(p: string, encoding: "binary"): Promise', gave the following error.
Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
Type 'undefined' is not assignable to type 'string'.

No overload matches this call.
Overload 1 of 2, '(values: [] | readonly unknown[]): Promise<unknown[] | []>', gave the following error.
Argument of type 'Promise[] | undefined' is not assignable to parameter of type '[] | readonly unknown[]'.
Type 'undefined' is not assignable to type '[] | readonly unknown[]'.
Overload 2 of 2, '(values: Iterable<void | PromiseLike>): Promise<void[]>', gave the following error.
Argument of type 'Promise[] | undefined' is not assignable to parameter of type 'Iterable<void | PromiseLike>'.
Type 'undefined' is not assignable to type 'Iterable<void | PromiseLike>'.

No overload matches this call.
Overload 1 of 2, '(o: {}): string[]', gave the following error.
Argument of type 'TestingConfig | undefined' is not assignable to parameter of type '{}'.
Type 'undefined' is not assignable to type '{}'.
Overload 2 of 2, '(o: object): string[]', gave the following error.
Argument of type 'TestingConfig | undefined' is not assignable to parameter of type 'object'.
Type 'undefined' is not assignable to type 'object'.
TS2790 15
Error messages The operand of a 'delete' operator must be optional.
TS2538 7
Error messages Type 'undefined' cannot be used as an index type.

Type 'null' cannot be used as an index type.
TS2416 4
Error messages Property 'get' in type 'Cache' is not assignable to the same property in base type 'Cache'.
Type '(key: string) => Promise<string | null>' is not assignable to type '(key: string) => Promise'.
Type 'Promise<string | null>' is not assignable to type 'Promise'.
Type 'string | null' is not assignable to type 'string'.
Type 'null' is not assignable to type 'string'.

Property 'getMemoryStats' in type 'Cache' is not assignable to the same property in base type 'Cache'.
Type '() => string | null' is not assignable to type '() => string'.
Type 'string | null' is not assignable to type 'string'.
Type 'null' is not assignable to type 'string'.

Property 'find' in type 'E2EElement' is not assignable to the same property in base type 'E2EElementInternal'.
Type '(selector: string) => Promise<E2EElement | null>' is not assignable to type '(selector: FindSelector) => Promise'.
Type 'Promise<E2EElement | null>' is not assignable to type 'Promise'.
Type 'E2EElement | null' is not assignable to type 'E2EElement'.
Type 'null' is not assignable to type 'E2EElement'.

Property 'findAll' in type 'E2EElement' is not assignable to the same property in base type 'E2EElementInternal'.
Type '(selector: string) => Promise<E2EElement[]>' is not assignable to type '(selector: FindSelector) => Promise<E2EElement[]>'.
Type 'Promise<import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-element").E2EElement[]>' is not assignable to type 'Promise<import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-declarations").E2EElement[]>'.
Type 'import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-element").E2EElement[]' is not assignable to type 'import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-declarations").E2EElement[]'.
Type 'import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-element").E2EElement' is not assignable to type 'import("/home/runner/work/stencil/stencil/src/testing/puppeteer/puppeteer-declarations").E2EElement'.
The types returned by 'find(...)' are incompatible between these types.
Type 'Promise<E2EElement | null>' is not assignable to type 'Promise'.
TS2533 3
Error messages Object is possibly 'null' or 'undefined'.
TS2488 2
Error messages Type 'Diagnostic[] | undefined' must have a 'Symbol.iterator' method that returns an iterator.

Type 'string[] | undefined' must have a 'Symbol.iterator' method that returns an iterator.
TS2684 1
Error messages The 'this' context of type 'ResolveIdHook | undefined' is not assignable to method's 'this' of type 'Function'.
Type 'undefined' is not assignable to type 'Function'.
TS2464 1
Error messages A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
TS2430 1
Error messages Interface 'SerializeOpts' incorrectly extends interface 'SerializeCssOptions'.
Types of property 'usedSelectors' are incompatible.
Type 'UsedSelectors | null' is not assignable to type 'UsedSelectors | undefined'.
Type 'null' is not assignable to type 'UsedSelectors | undefined'.
TS2339 1
Error messages Property 'kind' does not exist on type 'never'.
TS2774 1
Error messages This condition will always return true since this function is always defined. Did you mean to call it instead?

Unused exports report

There are 25 unused exports on this PR. That's the same number of errors on main, so at least we're not creating new ones!

Unused exports
File Line Identifier
src/version.ts 8 transpilerId
src/screenshot/screenshot-fs.ts 18 readScreenshotData
src/utils/index.ts 85 XML_NS
src/utils/index.ts 3 toLowerCase
src/utils/index.ts 84 isDefined
src/utils/index.ts 85 isUndefined
src/utils/index.ts 130 parseJson
src/cli/telemetry/helpers.ts 13 TERMINAL_INFO
src/compiler/app-core/app-data.ts 3 BUILD
src/compiler/app-core/app-data.ts 88 Env
src/compiler/app-core/app-data.ts 90 NAMESPACE
src/compiler/app-core/bundle-app-core.ts 43 DEFAULT_CORE
src/compiler/app-core/bundle-app-core.ts 47 DEFAULT_ENTRY
src/compiler/fs-watch/fs-watch-rebuild.ts 46 isScriptExt
src/compiler/fs-watch/fs-watch-rebuild.ts 49 isStyleExt
src/compiler/fs-watch/fs-watch-rebuild.ts 68 updateCacheFromRebuild
src/compiler/prerender/host-config.ts 4 generateHostConfig
src/compiler/prerender/host-config.ts 276 DEFAULT_MODE
src/compiler/style/css-imports.ts 247 replaceNodeModuleUrl
src/testing/platform/testing-platform.ts 28 cssVarShim
src/testing/puppeteer/puppeteer-declarations.ts 513 WaitForEventOptions
src/client/polyfills/css-shim/utils.ts 1 GLOBAL_SCOPE
src/compiler/config/outputs/validate-collection.ts 16 getCollectionDistDir
src/compiler/sys/fetch/fetch-utils.ts 34 getStencilInternalDtsUrl
src/compiler/transformers/component-native/tranform-to-native-component.ts 13 transformToNativeComponentText

@alicewriteswrongs
fix(config): fix faulty build output w/ --esm flag
ccd5584 
Stencil v2.16.0 introduced a regression, the symptoms of which are
described here: #3403. Git
bisect showed that this commit was the culprit:
cca8951.

What was the regression?
------------------------

What the user observed is that after upgrading from Stencil version
2.15.2 to version 2.16.0 the build output changed. With 2.15.2, when
calling stencil like so:

```
stencil build --docs --dev --esm
```

the build output looked something like this:

```
dist
├── cjs
├── collection
│   ├── components
│   ├── test
│   └── utils
├── esm
│   └── polyfills
├── loader
├── stencil-one
└── types
```

Whereas after upgrading to 2.16.0 the output looked something like this:

```
dist
├── stencil-one
└── types
```

Why did the built output change?
--------------------------------

Stencil previously explicitly supported a `--esm` boolean command-line
flag. Before [the change to remove the legacy
compiler](63595bc)
this flag was used to control whether the output would be ES modules or
not (I _think_).

The flag was removed from the supported arguments list in [that same
commit](63595bc#diff-e6a96bc13cd5c047a16a1888b27e88af52903e89848de68b0072d32ea11b1208L196),
however some code that implicitly depended on the argument remained in
the codebase, and it was eventually (partially) [added back to the
codebase later on](#2339) but,
although a change was made to `src/cli/parse-flags.ts` to support
parsing the flag, it was *not* added to the `ConfigFlags` interface,
which is intended to capture the names and types of all CLI arguments.

Related to this history of the flag being added and removed from
Stencil, on `src/compiler/config/validate-config.ts` there was, prior to
the bad commit which introduced this regression, a call to the
`setBooleanConfig` helper that looked like this:

```ts
setBooleanConfig(config, 'buildDist', 'esm', !config.devMode || config.buildEs5);
```

This line creates an undocumented dependency on the `--esm` command-line
flag, where it's presence or absence changes what the value of
`config.buildDist` will be.

This happens because of the implementation of `setBooleanConfig`, where
if a value is passed for the third positional argument it will look at
the command-line arguments passed to the Stencil CLI in order to
find a value to set on the `Config` object. The relevant code looks
like this:

```ts
export const setBooleanConfig = <K extends keyof d.Config>(
  config: d.UnvalidatedConfig,
  configName: (K & keyof d.ConfigFlags) | K,
  flagName: keyof d.ConfigFlags | null,
  defaultValue: d.Config[K]
) => {
  if (flagName) {
    const flagValue = config.flags?.[flagName];
    if (isBoolean(flagValue)) {
      config[configName] = flagValue;
    }
  }
```

The [commit that introduced the
regression](cca8951#diff-53c120bef3205f89229fbe98a5aadfcb51012ead144729ade2fc597c1e9ad5e9R64)
changed the above call to `setBooleanConfig` to this:

```ts
setBooleanConfig(config, 'buildDist', null, !config.devMode || config.buildEs5);
```

The user observed the regression because they were using the `--esm`
command-line flag with their project, so on any stencil version <=
2.15.2 the presence of that flag was causing `config.buildDist` to be
set to `true`, resulting in the expected build output above. In 2.16.0
the behavior of the `--esm` flag was broken by change from `"esm"` to
`null`.

Why was the change introduced?
------------------------------

This change was introduced because `"esm"` was not listed as a supported
command-line argument on the `ConfigFlags` interface and the third
position argument to `setBooleanConfig` has type `keyof d.ConfigFlags`,
so the change to `null` was in line with what `setBooleanConfig` expects
for its arguments. The commit author (me!) was unsure of whether to make
this change or not, and there was [some discussion on the
PR](#3335 (comment)).
Light testing did not turn up the regression because we weren't
using the `--esm` flag.

What is the fix?
----------------

The fix is to add `esm` to the `ConfigFlags` interface and to revert the
bad line in `src/compiler/config/validate-config.ts`. This will allow
anyone who is currently using the `--esm` flag to keep doing so.

This fix does not deal with whether or not we want to continue
supporting the `--esm` flag — it's possible that a larger refactor to
how the `buildDist` variable is used throughout the codebase is in order
— but doing this will unblock any users who are currently depending on
Stencil's previous, undocumented behavior.

I think this is the right fix for now, however, because an API change
like this should not happen on a minor release, so the behavior of the
compiler changing in this way should be viewed as a bug and we should
take the steps to restore the old behavior.

Any larger lessons learned?
---------------------------

Part of the reason for the regression was that the CLI argument parsing
code does not have a type level contract with the interface into which
the CLI args are parsed. In particular, there are lists of supported CLI
flags in `src/cli/parse-flags.ts` but these have _no connection_ with
the `ConfigFlags` interface, which describes the shape of the object
into which they are going to be shoved after their values are parsed.

This means that although we have an interface that sort of _claims_, at
least implicitly, because of how it's named, to enumerate the possible /
allowed CLI arguments, we aren't actually utilizing the type system to
enforce a tighter contract between the parsing code and that interface,
so there is a possibility of the arguments declared in one or the other
of these two places (the `parse-flags.ts` code or the `ConfigFlags`
interface) drifting from the other.

To address that root cause I think we should implement something to
declare these properties in one place. For instance, we could declare a
`ReadonlyArray` of Boolean flags, another of String flags, and then use
types derived from those as keys for the `ConfigFlags` argument.

Additionally, several of the commits in the history of the repository
which had to do with this flag have no discussion, documentation, or
context provided for the changes.
rwaskiewicz
rwaskiewicz approved these changes Jun 3, 2022
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LGTM

@rwaskiewicz rwaskiewicz merged commit a847a6e into main Jun 3, 2022
@rwaskiewicz rwaskiewicz deleted the ap/fix-loader-build-issue branch June 3, 2022 03:15
@alicewriteswrongs alicewriteswrongs mentioned this pull request Jun 16, 2022
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