fix: Fixing get_original_terragrunt_dir()

Author: yhakbar

pkg/config/dependency.go

@@ -312,6 +312,7 @@ func decodeDependencies(ctx context.Context, pctx *ParsingContext, l log.Logger,
 			return nil, err
 		}
 
+		depCtx.OriginalTerragruntConfigPath = depPath
 		depCtx.DownloadDir = filepath.Join(filepath.Dir(depPath), util.TerragruntCacheDir)
 
 		if depCtx.IAMRoleOptions != depCtx.OriginalIAMRoleOptions {
@@ -398,6 +399,8 @@ func checkForDependencyBlockCycles(ctx context.Context, pctx *ParsingContext, l
 			return err
 		}
 
+		dependencyContext.OriginalTerragruntConfigPath = dependencyPath
+
 		if err := checkForDependencyBlockCyclesUsingDFS(ctx, dependencyContext, l, dependencyPath, &visitedPaths, &currentTraversalPaths); err != nil {
 			return err
 		}
@@ -441,6 +444,8 @@ func checkForDependencyBlockCyclesUsingDFS(
 			return err
 		}
 
+		dependencyContext.OriginalTerragruntConfigPath = dependencyPath
+
 		if err := checkForDependencyBlockCyclesUsingDFS(ctx, dependencyContext, l, dependencyPath, visitedPaths, currentTraversalPaths); err != nil {
 			return err
 		}

pkg/config/dependency_test.go

@@ -188,6 +188,37 @@ dependency "enabled" {
 
 // TestDisabledDependencyWithEmptyConfigPath verifies that disabled dependencies
 // with empty config_path don't cause errors.
+// TestDependencyOriginalTerragruntDir verifies that when parsing a dependency's
+// config during cycle detection, get_original_terragrunt_dir() returns the
+// dependency's directory, not the caller's directory.
+//
+// Regression test: when unit-a depends on unit-b, and unit-b's config chain
+// calls get_original_terragrunt_dir(), it must resolve to unit-b's directory so
+// that paths constructed from it point to files that exist alongside unit-b.
+func TestDependencyOriginalTerragruntDir(t *testing.T) {
+	t.Parallel()
+
+	filename, err := filepath.Abs(
+		filepath.Join(
+			"../..",
+			"test",
+			"fixtures",
+			"regressions",
+			"dependency-original-terragrunt-dir",
+			"unit-a",
+			"terragrunt.hcl",
+		),
+	)
+	require.NoError(t, err)
+
+	ctx, pctx := newTestParsingContext(t, filename)
+	pctx.OriginalTerragruntConfigPath = filename
+	pctx.SkipOutput = true
+
+	_, err = config.ParseConfigFile(ctx, pctx, logger.CreateLogger(), filename, nil)
+	require.NoError(t, err)
+}
+
 func TestDisabledDependencyWithEmptyConfigPath(t *testing.T) {
 	t.Parallel()
 

test/fixtures/regressions/dependency-original-terragrunt-dir/unit-a/terragrunt.hcl

@@ -0,0 +1,11 @@
+dependency "unit_b" {
+  config_path  = "../unit-b"
+  skip_outputs = true
+  mock_outputs = {
+    app_name = "mock"
+  }
+}
+
+inputs = {
+  dep_name = dependency.unit_b.outputs.app_name
+}

test/fixtures/regressions/dependency-original-terragrunt-dir/unit-b/_common.hcl

@@ -0,0 +1,3 @@
+locals {
+  app_name = "myapp"
+}

test/fixtures/regressions/dependency-original-terragrunt-dir/unit-b/common.hcl

@@ -0,0 +1,5 @@
+locals {
+  original_dir    = get_original_terragrunt_dir()
+  common_config   = read_terragrunt_config("${local.original_dir}/_common.hcl")
+  app_name        = local.common_config.locals.app_name
+}

test/fixtures/regressions/dependency-original-terragrunt-dir/unit-b/terragrunt.hcl

@@ -0,0 +1,8 @@
+locals {
+  common   = read_terragrunt_config("common.hcl")
+  app_name = local.common.locals.app_name
+}
+
+inputs = {
+  app_name = local.app_name
+}