feat: add 'create' subcommand to scaffold helmfile deployment projects (#2574)

* feat: add 'create' subcommand to scaffold helmfile deployment projects

Add 'helmfile create [NAME]' command that generates a best-practice
helmfile project structure with:
- helmfile.yaml with commented examples (helmDefaults, repositories,
  environments, releases)
- environments/default.yaml for environment-specific values
- values/.gitkeep placeholder for release values

Supports --output-dir/-o for custom output path and --force to
overwrite existing files. Validates project name to prevent path
traversal.

Signed-off-by: yxxhero <aiopsclub@163.com>

* fix: add overwrite protection for all scaffold files and unit tests for create command

- pkg/app/create.go: extract writeFileIfNotExists helper that respects the
  --force flag; all three scaffold files (helmfile.yaml,
  environments/default.yaml, values/.gitkeep) now refuse to overwrite
  without --force
- pkg/config/create.go: ValidateConfig now checks all three scaffold paths
  and reports every already-existing file in a single error before
  proceeding, instead of only checking helmfile.yaml
- pkg/app/create_test.go: add unit tests covering new directory, current
  directory, per-file overwrite rejection without --force, and full
  overwrite with --force

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/eb6d9e4b-0f72-4e26-b841-e1e39a2b2e83

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: remove redundant absDir from ValidateConfig error message

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/eb6d9e4b-0f72-4e26-b841-e1e39a2b2e83

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: address create command review feedback

- cmd/create.go: add config.NewCLIConfigImpl() call for consistency with other
  subcommands; update --force flag help text to list all overwritten files
- pkg/config/create.go: delegate to c.GlobalImpl.ValidateConfig() at end of
  ValidateConfig() for global option validation (--color/--no-color)
- pkg/config/create_test.go: add unit tests for CreateImpl.ValidateConfig()
  covering path separator rejection, '..' rejection, existing-file detection
  per-file and with --force, and global color conflict delegation

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/6327d657-5888-4b94-85fb-def80c0a193f

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: clarify test helper name and comment in create_test.go

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/6327d657-5888-4b94-85fb-def80c0a193f

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: atomic preflight check in App.Create before any writes

Refactor Create to collect all conflicting scaffold paths up front
before writing anything. When --force is not set and any scaffold file
already exists, the command returns a single error listing all
conflicts without touching the filesystem.

Also removes the now-unnecessary writeFileIfNotExists helper and adds a
test (TestCreate_PreflightAtomicOnLaterConflict) verifying that a
conflict on a later file (e.g. environments/default.yaml) prevents even
the first file (helmfile.yaml) from being created.

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/aae6f2e6-7f9e-42b8-afa3-78edd3215127

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: handle non-IsNotExist Stat errors in preflight check; add whitespace name test; fix gci formatting

- pkg/app/create.go: treat os.Stat errors that are NOT os.IsNotExist as
  hard errors in the preflight scan, surfacing permission/IO issues before
  any writes happen; remove trailing blank line that caused gci failure
- pkg/config/create.go: same non-IsNotExist error handling in ValidateConfig
- pkg/config/create_test.go: add TestCreateImpl_ValidateConfig_WhitespaceOnlyName
  covering the "   " (whitespace-only) name rejection branch

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/d6574f56-f46d-46f7-99d9-e0b0b897b3b5

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* refactor: eliminate duplicated scaffold existence check; use O_EXCL for TOCTOU protection

- pkg/config/create.go: remove file-existence check from ValidateConfig
  (duplicate of App.Create's preflight); ValidateConfig now only validates
  the project name and delegates to GlobalImpl.ValidateConfig. Remove unused
  os/path/filepath imports.
- pkg/app/create.go: add writeScaffoldFile helper that uses O_CREATE|O_EXCL
  when force=false, so a file appearing between the preflight check and the
  actual write is caught rather than silently overwritten (TOCTOU protection).
- pkg/config/create_test.go: remove four file-existence tests that tested the
  now-deleted ValidateConfig logic; file-conflict coverage remains in
  pkg/app/create_test.go. Simplify ValidName and GlobalColorConflict tests.

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/82f82e72-934f-416c-8662-5060e92284fa

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: wrap O_EXCL error with --force hint; add writeScaffoldFile unit tests

- pkg/app/create.go: wrap os.IsExist error from writeScaffoldFile with a
  message that names the conflicting file and suggests --force, so the user
  gets actionable output even in the TOCTOU case
- pkg/app/create_test.go: add TestWriteScaffoldFile_CreatesNewFile,
  TestWriteScaffoldFile_ExistingFileNoForce, and
  TestWriteScaffoldFile_ExistingFileWithForce to cover the helper directly

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/82f82e72-934f-416c-8662-5060e92284fa

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: wrap App.Create errors in *app.Error; reject '.' as project name; add '.' name test

- pkg/app/create.go: wrap all App.Create fmt.Errorf returns with appError("", ...)
  so toCLIError produces a clean user-friendly message instead of
  "unexpected error: *fmt.wrapError: ..."
- pkg/config/create.go: reject "." as a NAME alongside ".." to prevent
  accidentally scaffolding into the current directory via a named argument
- pkg/config/create_test.go: add TestCreateImpl_ValidateConfig_NameDot

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/6d64508e-2d66-47e9-a02a-7669a2f481b7

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: drop unused outputDir param from test helper to fix unparam lint error

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/11cd65e9-c5ef-4195-9375-bc929169616b

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

* fix: drop unused force param from test helper to fix unparam lint error

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/0e1bdac5-708f-4615-ae6d-e22fc1e921f2

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

---------

Signed-off-by: yxxhero <aiopsclub@163.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

cmd/create.go

@@ -0,0 +1,45 @@
+package cmd
+
+import (
+	"github.com/spf13/cobra"
+
+	"github.com/helmfile/helmfile/pkg/app"
+	"github.com/helmfile/helmfile/pkg/config"
+)
+
+func NewCreateCmd(globalCfg *config.GlobalImpl) *cobra.Command {
+	options := config.NewCreateOptions()
+	cmd := &cobra.Command{
+		Use:   "create [NAME]",
+		Short: "Create a helmfile deployment project scaffold",
+		Long: `Create a helmfile deployment project with best-practice directory structure.
+
+Generates:
+  - helmfile.yaml          Main configuration with commented examples
+  - environments/           Environment-specific value files
+  - values/                 Release-specific value files
+
+If NAME is provided, creates the project in a new directory named NAME.
+Otherwise, creates the project in the current directory.`,
+		Args: cobra.MaximumNArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) > 0 {
+				options.Name = args[0]
+			}
+			createImpl := config.NewCreateImpl(globalCfg, options)
+			if err := config.NewCLIConfigImpl(createImpl.GlobalImpl); err != nil {
+				return err
+			}
+			if err := createImpl.ValidateConfig(); err != nil {
+				return err
+			}
+			a := app.New(createImpl)
+			return toCLIError(createImpl.GlobalImpl, a.Create(createImpl))
+		},
+	}
+	f := cmd.Flags()
+	f.StringVarP(&options.OutputDir, "output-dir", "o", "", "Output directory (default: NAME or current directory)")
+	f.BoolVar(&options.Force, "force", false, "Overwrite existing scaffold files (helmfile.yaml, environments/default.yaml, values/.gitkeep)")
+
+	return cmd
+}

cmd/root.go

@@ -92,6 +92,7 @@ func NewRootCmd(globalConfig *config.GlobalOptions) (*cobra.Command, error) {
 	}
 
 	cmd.AddCommand(
+		NewCreateCmd(globalImpl),
 		NewInitCmd(globalImpl),
 		NewApplyCmd(globalImpl),
 		NewBuildCmd(globalImpl),