chore: discovery helpers

Author: denis256

internal/discovery/helpers.go

@@ -1,6 +1,7 @@
 package discovery
 
 import (
+	iofs "io/fs"
 	"os"
 	"path/filepath"
 	"slices"
@@ -290,8 +291,14 @@ func stackDependencyPaths(fs vfs.FS, depPaths []string, c component.Component) (
 	expanded := make([]string, 0, len(depPaths))
 
 	for _, depPath := range depPaths {
-		// Only expand directories: dependency paths can also point at non-default-named config files (e.g. another-name.hcl), which the stack-file parser would otherwise reject as "not a directory".
-		if info, statErr := fs.Stat(depPath); statErr != nil || !info.IsDir() {
+		info, statErr := fs.Stat(depPath)
+		// Real I/O errors (permission denied, etc.) must surface so a malformed DAG isn't silently produced; only ENOENT is treated as "keep the raw path".
+		if statErr != nil && !errors.Is(statErr, iofs.ErrNotExist) {
+			return nil, NewStackDependencyExpansionError(depPath, statErr)
+		}
+
+		// Dependency paths can also point at non-default-named config files (e.g. another-name.hcl), which the stack-file parser would otherwise reject as "not a directory".
+		if statErr != nil || !info.IsDir() {
 			expanded = append(expanded, depPath)
 			continue
 		}

internal/discovery/stack_dependency_expansion_error_test.go

@@ -1,6 +1,7 @@
 package discovery_test
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/gruntwork-io/terragrunt/internal/discovery"
@@ -36,3 +37,25 @@ func TestStackDependencyExpansionError_Unwrap(t *testing.T) {
 	// errors.Is must reach the leaf via Unwrap chain.
 	require.ErrorIs(t, wrapped, innerErr)
 }
+
+// Locks the full unwrap chain: discovery wrapper -> MalformedDependencyError -> underlying sentinel.
+func TestStackDependencyExpansionError_UnwrapNestedSentinel(t *testing.T) {
+	t.Parallel()
+
+	sentinel := errors.New("hcl diag root cause")
+
+	innerErr := hclparse.MalformedDependencyError{
+		Err:      sentinel,
+		FilePath: "/some/path/terragrunt.autoinclude.hcl",
+		Name:     "vpc",
+		Reason:   "config_path: <hcl diag>",
+	}
+
+	wrapped := discovery.NewStackDependencyExpansionError("/path/to/dep", innerErr)
+
+	require.ErrorIs(t, wrapped, sentinel)
+
+	var malformed hclparse.MalformedDependencyError
+	require.ErrorAs(t, wrapped, &malformed)
+	require.ErrorIs(t, malformed, sentinel)
+}

internal/hclparse/autoinclude_test.go

@@ -1,7 +1,6 @@
 package hclparse_test
 
 import (
-	"errors"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -418,23 +417,19 @@ func TestAutoIncludeDependencyPaths_FileParseErrorOnSyntaxError(t *testing.T) {
 	require.ErrorAs(t, err, &fpe)
 }
 
-func TestAutoIncludeDependencyPaths_UnexpectedBodyTypeOnJSON(t *testing.T) {
+func TestAutoIncludeDependencyPaths_FileParseErrorOnJSON(t *testing.T) {
 	t.Parallel()
 
 	fs := vfs.NewMemMapFS()
 	jsonBody := `{"dependency": {"vpc": {"config_path": "../vpc"}}}`
-	require.NoError(t, vfs.WriteFile(fs, filepath.Join("/test", hclparse.AutoIncludeFile+".json"), []byte(jsonBody), 0644))
 	require.NoError(t, vfs.WriteFile(fs, filepath.Join("/test", hclparse.AutoIncludeFile), []byte(jsonBody), 0644))
 
 	paths, err := hclparse.AutoIncludeDependencyPaths(fs, "/test")
 	require.Error(t, err)
 	assert.Nil(t, paths)
 
 	var fpe hclparse.FileParseError
-
-	var ube hclparse.UnexpectedBodyTypeError
-
-	assert.True(t, errors.As(err, &fpe) || errors.As(err, &ube), "expected FileParseError or UnexpectedBodyTypeError, got %T: %v", err, err)
+	require.ErrorAs(t, err, &fpe)
 }
 
 // parseHCLBody is a test helper that parses an HCL string and returns the body.

internal/hclparse/stack_test.go

@@ -353,6 +353,10 @@ func TestParseStackFileFromPath_StackDirIsFileReturnsError(t *testing.T) {
 	result, err := hclparse.ParseStackFileFromPath(vfs.NewOSFS(), filePath)
 	require.Error(t, err)
 	assert.Nil(t, result)
+
+	var readErr hclparse.FileReadError
+	require.ErrorAs(t, err, &readErr)
+	assert.Equal(t, filepath.Join(filePath, "terragrunt.stack.hcl"), readErr.FilePath)
 }
 
 func TestParseStackFileFromPath_Symlink(t *testing.T) {
@@ -403,7 +407,7 @@ unit "vpc" {
 	paths, err := hclparse.UnitPathsFromStackDir(vfs.NewOSFS(), symlinkDir)
 	require.NoError(t, err)
 	require.Len(t, paths, 1)
-	// Path should resolve to the real directory, not the symlink target.
+	// Path should resolve to the real directory, not the symlink path.
 	assert.Contains(t, paths[0], "real-stack")
 	assert.NotContains(t, paths[0], "symlinked-stack")
 }

pkg/config/stack_autoinclude_internal_test.go

@@ -37,7 +37,7 @@ func TestStackConfigHasAutoInclude(t *testing.T) {
 	}
 }
 
-// JSON-format remain bodies aren't *hclsyntax.Body and must return false: autoinclude blocks are only supported in native HCL.
+// Non-*hclsyntax.Body remain bodies (e.g. hcl.EmptyBody, JSON-format bodies) must return false: autoinclude blocks are only inspected in native HCL syntax.
 func TestHasAutoIncludeInBody_NonSyntaxBodyReturnsFalse(t *testing.T) {
 	t.Parallel()
 

test/integration_stack_dependencies_test.go

@@ -496,7 +496,7 @@ func TestStackDepsAutoIncludeLoudFailOnParserLimit(t *testing.T) {
 	stdout, stderr, err := helpers.RunTerragruntCommandWithOutput(t,
 		"terragrunt stack generate --experiment stack-dependencies --working-dir "+rootPath)
 
-	require.Error(t, err, "stack generate must fail loudly when autoinclude is declared and the two-pass parser cannot decode the stack file")
+	require.Error(t, err, "stack generate must return an error when autoinclude is declared and the two-pass parser cannot decode the stack file")
 	assert.Contains(t, err.Error()+"\n"+stdout+stderr, "failed to parse autoinclude block")
 	require.NoFileExists(t, filepath.Join(rootPath, inthclparse.StackDir, "subnet", inthclparse.AutoIncludeFile))
 }
@@ -538,7 +538,7 @@ func TestStackDepsAutoIncludeLoudFailViaInclude(t *testing.T) {
 	stdout, stderr, err := helpers.RunTerragruntCommandWithOutput(t,
 		"terragrunt stack generate --experiment stack-dependencies --working-dir "+rootPath)
 
-	require.Error(t, err, "stack generate must fail loudly when autoinclude is declared in an included stack file")
+	require.Error(t, err, "stack generate must return an error when autoinclude is declared in an included stack file")
 	assert.Contains(t, err.Error()+"\n"+stdout+stderr, "failed to parse autoinclude block")
 	require.NoFileExists(t, filepath.Join(rootPath, inthclparse.StackDir, "subnet", inthclparse.AutoIncludeFile))
 }
@@ -554,7 +554,7 @@ func TestStackDepsAutoIncludeLoudFailViaDynamicInclude(t *testing.T) {
 	stdout, stderr, err := helpers.RunTerragruntCommandWithOutput(t,
 		"terragrunt stack generate --experiment stack-dependencies --working-dir "+rootPath)
 
-	require.Error(t, err, "stack generate must fail loudly when autoinclude is reachable via an expression-based include path")
+	require.Error(t, err, "stack generate must return an error when autoinclude is reachable via an expression-based include path")
 	assert.Contains(t, err.Error()+"\n"+stdout+stderr, "failed to parse autoinclude block")
 	require.NoFileExists(t, filepath.Join(rootPath, inthclparse.StackDir, "subnet", inthclparse.AutoIncludeFile))
 }