Merge #13233

13233: Don't save empty config values to the config file in new r=Frassle a=Frassle


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# Description

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Fixes #4081

Also plumbs the prompt function down to `promptForConfig` so this can be tested.


## Checklist

- [x] I have run `make tidy` to update any new dependencies
- [x] I have run `make lint` to verify my code passes the lint check
  - [ ] I have formatted my code using `gofumpt`

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- [x] I have added tests that prove my fix is effective or that my feature works
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User-facing changes require a CHANGELOG entry.
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- [x] I have run `make changelog` and committed the `changelog/pending/<file>` documenting my change
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Co-authored-by: Fraser Waters <fraser@pulumi.com>

changelog/pending/20230621--cli-new--fix-empty-config-values-being-added-to-the-config-file-as-part-of-new.yaml

@@ -0,0 +1,4 @@
+changes:
+- type: fix
+  scope: cli/new
+  description: Fix empty config values being added to the config file as part of `new`.

pkg/cmd/pulumi/new.go

@@ -296,7 +296,10 @@ func runNew(ctx context.Context, args newArgs) error {
 
 	// Prompt for config values (if needed) and save.
 	if !args.generateOnly {
-		err = handleConfig(ctx, proj, s, args.templateNameOrURL, template, args.configArray, args.yes, args.configPath, opts)
+		err = handleConfig(
+			ctx, args.prompt, proj, s,
+			args.templateNameOrURL, template, args.configArray,
+			args.yes, args.configPath, opts)
 		if err != nil {
 			return err
 		}
@@ -848,6 +851,7 @@ func parseConfig(configArray []string, path bool) (config.Map, error) {
 // value when prompting instead of the default value specified in templateConfig.
 func promptForConfig(
 	ctx context.Context,
+	prompt promptForValueFunc,
 	project *workspace.Project,
 	stack backend.Stack,
 	templateConfig map[string]workspace.ProjectTemplateConfigValue,
@@ -932,17 +936,22 @@ func promptForConfig(
 		}
 
 		// Prepare the prompt.
-		prompt := prettyKey(k)
+		promptText := prettyKey(k)
 		if templateConfigValue.Description != "" {
-			prompt = prompt + ": " + templateConfigValue.Description
+			promptText = promptText + ": " + templateConfigValue.Description
 		}
 
 		// Prompt.
-		value, err := promptForValue(yes, prompt, defaultValue, secret, nil, opts)
+		value, err := prompt(yes, promptText, defaultValue, secret, nil, opts)
 		if err != nil {
 			return nil, err
 		}
 
+		if value == "" {
+			// Don't add empty values to the config.
+			continue
+		}
+
 		// Encrypt the value if needed.
 		var v config.Value
 		if secret {

pkg/cmd/pulumi/new_test.go

@@ -19,10 +19,13 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/pulumi/pulumi/pkg/v3/backend"
+	"github.com/pulumi/pulumi/pkg/v3/backend/display"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource/config"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/workspace"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -296,6 +299,45 @@ func TestGeneratingProjectWithExistingPromptedNameSucceeds(t *testing.T) {
 	assert.Equal(t, projectName, proj.Name.String())
 }
 
+//nolint:paralleltest // changes directory for process
+func TestCreatingProjectWithEmptyConfig(t *testing.T) {
+	// Regression test for https://github.com/pulumi/pulumi/issues/4081
+	skipIfShortOrNoPulumiAccessToken(t)
+
+	tempdir := t.TempDir()
+	chdir(t, tempdir)
+	uniqueProjectName := filepath.Base(tempdir) + "test"
+
+	prompt := func(yes bool, valueType string, defaultValue string, secret bool,
+		isValidFn func(value string) error, opts display.Options,
+	) (string, error) {
+		if strings.HasPrefix(valueType, "aws:region:") {
+			return "", nil
+		}
+		return defaultValue, nil
+	}
+
+	args := newArgs{
+		name:              uniqueProjectName,
+		stack:             stackName,
+		interactive:       true,
+		prompt:            prompt,
+		secretsProvider:   "default",
+		templateNameOrURL: "aws-typescript",
+	}
+
+	err := runNew(context.Background(), args)
+	require.NoError(t, err)
+
+	proj := loadProject(t, tempdir)
+	projStack, err := workspace.LoadProjectStack(proj, filepath.Join(tempdir, "Pulumi."+stackName+".yaml"))
+	require.NoError(t, err)
+
+	assert.NotContains(t, projStack.Config, config.MustMakeKey("aws", "region"))
+
+	removeStack(t, tempdir, stackName)
+}
+
 //nolint:paralleltest // changes directory for process
 func TestGeneratingProjectWithInvalidArgsSpecifiedNameFails(t *testing.T) {
 	skipIfShortOrNoPulumiAccessToken(t)

pkg/cmd/pulumi/up.go

@@ -302,7 +302,10 @@ func newUpCmd() *cobra.Command {
 		}
 
 		// Prompt for config values (if needed) and save.
-		if err = handleConfig(ctx, proj, s, templateNameOrURL, template, configArray, yes, path, opts.Display); err != nil {
+		if err = handleConfig(
+			ctx, promptForValue, proj, s,
+			templateNameOrURL, template, configArray,
+			yes, path, opts.Display); err != nil {
 			return result.FromError(err)
 		}
 
@@ -637,6 +640,7 @@ func validatePolicyPackConfig(policyPackPaths []string, policyPackConfigPaths []
 // handleConfig handles prompting for config values (as needed) and saving config.
 func handleConfig(
 	ctx context.Context,
+	prompt promptForValueFunc,
 	project *workspace.Project,
 	s backend.Stack,
 	templateNameOrURL string,
@@ -676,7 +680,7 @@ func handleConfig(
 		}
 
 		// Prompt for config as needed.
-		c, err = promptForConfig(ctx, project, s, template.Config, commandLineConfig, stackConfig, yes, opts)
+		c, err = promptForConfig(ctx, prompt, project, s, template.Config, commandLineConfig, stackConfig, yes, opts)
 		if err != nil {
 			return err
 		}