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Two ngcc fixes #32129

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commented Aug 14, 2019

This PR fixes two ngcc bugs:

  • Some downlevelings of export const DIRECTIVES = [...] eliminate the ts.Declaration, causing ngcc to not enumerate them when listing the exports of a module.
  • .d.ts files outside of the currently compiling package were indexed and used to match classes in the package. If such a .d.ts file shadowed the name of a class within the compilation, it could erroneously be targeted for editing.

With these changes, ngcc can compile nativescript-angular!

@alxhub alxhub requested review from angular/fw-compiler as code owners Aug 14, 2019

@googlebot googlebot added the cla: yes label Aug 14, 2019

@alxhub alxhub requested a review from gkalpak Aug 14, 2019

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A couple of minor comments. LGTM otherwise 👍
(Super excited to be able to compile nativescript-angular 🎉)

packages/compiler-cli/ngcc/test/helpers/utils.ts Outdated Show resolved Hide resolved

@alxhub alxhub force-pushed the alxhub:ngcc/inline-decls branch 2 times, most recently from a7c3621 to a1c375d Aug 14, 2019

alxhub added 2 commits Aug 13, 2019
fix(ivy): in ngcc, handle inline exports in commonjs code
One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:

```typescript
import * as foo from './foo';

@NgModule({
  directives: [foo.DIRECTIVES],
})
```

In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.

When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.

```typescript
export const DIRECTIVES = [
  FooDir,
  BarDir,
];
```

can be downleveled to:

```javascript
exports.DIRECTIVES = [
  FooDir,
  BarDir,
```

Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.

To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.
fix(ivy): ngcc should only index .d.ts exports within the package
ngcc needs to solve a unique problem when compiling typings for an
entrypoint: it must resolve a declaration within a .js file to its
representation in a .d.ts file. Since such .d.ts files can be used in deep
imports without ever being referenced from the "root" .d.ts, it's not enough
to simply match exported types to the root .d.ts. ngcc must build an index
of all .d.ts files.

Previously, this operation had a bug: it scanned all .d.ts files in the
.d.ts program, not only those within the package. Thus, if a class in the
program happened to share a name with a class exported from a dependency's
.d.ts, ngcc might accidentally modify the wrong .d.ts file, causing a
variety of issues downstream.

To fix this issue, ngcc's .d.ts scanner now limits the .d.ts files it
indexes to only those declared in the current package.
@alxhub

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commented Aug 15, 2019

Caretaker: I am the approver :)

AndrewKushnir added a commit that referenced this pull request Aug 15, 2019
fix(ivy): ngcc should only index .d.ts exports within the package (#3…
…2129)

ngcc needs to solve a unique problem when compiling typings for an
entrypoint: it must resolve a declaration within a .js file to its
representation in a .d.ts file. Since such .d.ts files can be used in deep
imports without ever being referenced from the "root" .d.ts, it's not enough
to simply match exported types to the root .d.ts. ngcc must build an index
of all .d.ts files.

Previously, this operation had a bug: it scanned all .d.ts files in the
.d.ts program, not only those within the package. Thus, if a class in the
program happened to share a name with a class exported from a dependency's
.d.ts, ngcc might accidentally modify the wrong .d.ts file, causing a
variety of issues downstream.

To fix this issue, ngcc's .d.ts scanner now limits the .d.ts files it
indexes to only those declared in the current package.

PR Close #32129
sabeersulaiman added a commit to sabeersulaiman/angular that referenced this pull request Sep 6, 2019
fix(ivy): in ngcc, handle inline exports in commonjs code (angular#32129
)

One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:

```typescript
import * as foo from './foo';

@NgModule({
  directives: [foo.DIRECTIVES],
})
```

In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.

When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.

```typescript
export const DIRECTIVES = [
  FooDir,
  BarDir,
];
```

can be downleveled to:

```javascript
exports.DIRECTIVES = [
  FooDir,
  BarDir,
```

Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.

To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.

PR Close angular#32129
sabeersulaiman added a commit to sabeersulaiman/angular that referenced this pull request Sep 6, 2019
fix(ivy): ngcc should only index .d.ts exports within the package (an…
…gular#32129)

ngcc needs to solve a unique problem when compiling typings for an
entrypoint: it must resolve a declaration within a .js file to its
representation in a .d.ts file. Since such .d.ts files can be used in deep
imports without ever being referenced from the "root" .d.ts, it's not enough
to simply match exported types to the root .d.ts. ngcc must build an index
of all .d.ts files.

Previously, this operation had a bug: it scanned all .d.ts files in the
.d.ts program, not only those within the package. Thus, if a class in the
program happened to share a name with a class exported from a dependency's
.d.ts, ngcc might accidentally modify the wrong .d.ts file, causing a
variety of issues downstream.

To fix this issue, ngcc's .d.ts scanner now limits the .d.ts files it
indexes to only those declared in the current package.

PR Close angular#32129
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