Reproduce #5124 via integration test to validate fix

Author: atmask

test/fixtures/stacks/exclude-template-module/live/project-A/module/main.tf

@@ -0,0 +1,8 @@
+variable "environment" {
+  type = string
+}
+
+output "environment" {
+  value = var.environment
+}
+

test/fixtures/stacks/exclude-template-module/live/project-A/module/terragrunt.hcl

@@ -0,0 +1,21 @@
+# Project A dpeendency on Project B using values
+dependency "project_b" {
+  config_path = "../../../project-B/.terragrunt-stack/${values.env}"
+
+  mock_outputs = {
+    project_b_output = "mock-project-b-output"
+  }
+
+  mock_outputs_allowed_terraform_commands = ["init", "validate", "plan"]
+}
+
+terraform {
+  source = "."
+}
+
+# This will fail parsing if module/ isn't excluded from discovery
+# because ${values} only exists in generated stack context, not during standalone parsing
+inputs = {
+  environment = values.env
+}
+

test/fixtures/stacks/exclude-template-module/live/project-A/terragrunt.stack.hcl

@@ -0,0 +1,18 @@
+# This stack references a template module that uses stack variables
+# The module/ directory should be excluded to avoid parsing errors
+
+unit "staging" {
+  source = "./module"
+  path   = "staging"
+  values = {
+    env = "staging"
+  }
+}
+
+unit "production" {
+  source = "./module"
+  path   = "production"
+  values = {
+    env = "production"
+  }
+}

test/fixtures/stacks/exclude-template-module/live/project-B/module/main.tf

@@ -0,0 +1,8 @@
+variable "environment" {
+  type = string
+}
+
+output "environment" {
+  value = var.environment
+}
+

test/fixtures/stacks/exclude-template-module/live/project-B/module/terragrunt.hcl

@@ -0,0 +1,10 @@
+terraform {
+  source = "."
+}
+
+# This will fail parsing if module/ isn't excluded from discovery
+# because ${values} only exists in generated stack context, not during standalone parsing
+inputs = {
+  environment = values.env
+}
+

test/fixtures/stacks/exclude-template-module/live/project-B/terragrunt.stack.hcl

@@ -0,0 +1,18 @@
+# This stack references a template module that uses stack variables
+# The module/ directory should be excluded to avoid parsing errors
+
+unit "staging" {
+  source = "./module"
+  path   = "staging"
+  values = {
+    env = "staging"
+  }
+}
+
+unit "production" {
+  source = "./module"
+  path   = "production"
+  values = {
+    env = "production"
+  }
+}

test/integration_stacks_test.go

@@ -49,6 +49,7 @@ const (
 	testFixtureReadStack                       = "fixtures/stacks/read-stack"
 	testFixtureStackSelfInclude                = "fixtures/stacks/self-include"
 	testFixtureStackNestedOutputs              = "fixtures/stacks/nested-outputs"
+	testFixtureStackExcludeTemplateModule      = "fixtures/stacks/exclude-template-module"
 	testFixtureStackNoValidation               = "fixtures/stacks/no-validation"
 	testFixtureStackTerragruntDir              = "fixtures/stacks/terragrunt-dir"
 	testFixtureStacksAllNoStackDir             = "fixtures/stacks/all-no-stack-dir"
@@ -126,6 +127,28 @@ func TestStacksGenerateBasicWithQueueExcludeDirFlag(t *testing.T) {
 	validateStackDir(t, path)
 }
 
+func TestStacksGenerateExcludeModuleWithStackVariables(t *testing.T) {
+	t.Parallel()
+
+	helpers.CleanupTerraformFolder(t, testFixtureStackExcludeTemplateModule)
+	tmpEnvPath := helpers.CopyEnvironment(t, testFixtureStackExcludeTemplateModule)
+	rootPath := util.JoinPath(tmpEnvPath, testFixtureStackExcludeTemplateModule, "live")
+
+	// The module/ directory contains terragrunt.hcl that uses ${values.env} and ${values.project}
+	// This test verifies that --queue-exclude-dir prevents parsing of template modules
+	_, stderr, err := helpers.RunTerragruntCommandWithOutput(
+		t,
+		"terragrunt stack run plan --queue-exclude-dir '**/module' --working-dir "+rootPath,
+	)
+	require.NoError(t, err)
+
+	// Verify only the app unit is in the execution queue (not the module-based one)
+	assert.Contains(t, stderr, "- Unit ./project-A/.terragrunt-stack/production")
+	assert.Contains(t, stderr, "- Unit ./project-A/.terragrunt-stack/staging")
+	assert.Contains(t, stderr, "- Unit ./project-B/.terragrunt-stack/production")
+	assert.Contains(t, stderr, "- Unit ./project-B/.terragrunt-stack/staging")
+}
+
 func TestStacksGenerateBasic(t *testing.T) {
 	t.Parallel()