fix: change detection of Terragrunt module source.

Signed-off-by: i4k <[email protected]>

CHANGELOG.md

@@ -22,6 +22,10 @@ Given a version number `MAJOR.MINOR.PATCH`, we increment the:
 
 ## Unreleased
 
+### Fixed
+
+- Fix Terragrunt modules change detection.
+
 ## v0.11.2
 
 ### Added

stack/manager_test.go

@@ -193,6 +193,17 @@ func TestListChangedStacks(t *testing.T) {
 				changed: []string{"/tg-stack"},
 			},
 		},
+		{
+			name: "single Terragrunt stack with single local Terraform module changed referenced with abspath",
+			repobuilder: func(t *testing.T) repository {
+				t.Helper()
+				return singleTerragruntStackWithSingleTerraformModuleChangedFromAbsPathSourceRepo(t, "force")
+			},
+			want: listTestResult{
+				list:    []string{"/tg-stack"},
+				changed: []string{"/tg-stack"},
+			},
+		},
 		{
 			name:        "Terragrunt stack changed due to referenced file changed",
 			repobuilder: terragruntStackChangedDueToReferencedFileChangedRepo,
@@ -765,6 +776,55 @@ func singleTerragruntStackWithSingleTerraformModuleChangedRepo(t *testing.T, ena
 	return repo
 }
 
+func singleTerragruntStackWithSingleTerraformModuleChangedFromAbsPathSourceRepo(t *testing.T, enabledOption string) repository {
+	repo := singleMergeCommitRepoNoStack(t)
+	test.WriteFile(t, repo.Dir, "terramate.tm.hcl", Doc(
+		Block("terramate",
+			Block("config",
+				Block("change_detection",
+					Block("terragrunt",
+						Str("enabled", enabledOption),
+					),
+				),
+			),
+		),
+	).String())
+	modules := test.Mkdir(t, repo.Dir, "modules")
+	module1 := test.Mkdir(t, modules, "module1")
+
+	repo.modules = append(repo.modules, module1)
+
+	stack := test.Mkdir(t, repo.Dir, "tg-stack")
+	root, err := config.LoadRoot(repo.Dir)
+	assert.NoError(t, err)
+	createStack(t, root, stack)
+
+	g := test.NewGitWrapper(t, repo.Dir, []string{})
+	assert.NoError(t, g.Checkout("testbranch", true), "create branch failed")
+
+	test.WriteFile(t, stack, "terragrunt.hcl", Doc(
+		Block("terraform",
+			Str("source", "${get_repo_root()}/modules/module1"),
+		),
+	).String())
+
+	test.WriteFile(t, module1, "main.tf", `# empty file`)
+
+	assert.NoError(t, g.Add(repo.Dir), "add files")
+	assert.NoError(t, g.Commit("files"), "commit files")
+
+	addMergeCommit(t, repo.Dir, "testbranch")
+	assert.NoError(t, g.DeleteBranch("testbranch"), "delete testbranch")
+
+	// now we branch again and modify the module
+	assert.NoError(t, g.Checkout("testbranch2", true), "create branch testbranch2 failed")
+
+	test.WriteFile(t, module1, "main.tf", `# changed file`)
+	assert.NoError(t, g.Add(module1), "add files")
+	assert.NoError(t, g.Commit("module changed"), "commit files")
+	return repo
+}
+
 func terragruntStackChangedDueToDependencyChangedRepo(t *testing.T) repository {
 	repo := singleMergeCommitRepoNoStack(t)
 	stack := test.Mkdir(t, repo.Dir, "tg-stack")

test/git.go

@@ -4,6 +4,7 @@
 package test
 
 import (
+	"path/filepath"
 	"testing"
 
 	"github.com/madlambda/spells/assert"
@@ -48,7 +49,10 @@ func EmptyRepo(t testing.TB, bare bool) string {
 	gw := NewGitWrapper(t, "", []string{})
 
 	repodir := TempDir(t)
-	err := gw.Init(repodir, DefBranch, bare)
+	// resolve symlinks
+	repodir, err := filepath.EvalSymlinks(repodir)
+	assert.NoError(t, err, "evaluating symlinks")
+	err = gw.Init(repodir, DefBranch, bare)
 	assert.NoError(t, err, "git init")
 
 	return repodir

tg/tg_module.go

@@ -136,6 +136,23 @@ func ScanModules(rootdir string, dir project.Path, trackDependencies bool) (Modu
 		tgMod := stack.Modules[0]
 		mod.Source = *tgConfig.Terraform.Source
 		dependsOn := map[project.Path]struct{}{}
+		st, err := os.Lstat(mod.Source)
+		if err == nil && st.IsDir() {
+			// if the source is a directory, we assume it is a local module.
+			if filepath.IsAbs(mod.Source) {
+				src, err := filepath.EvalSymlinks(mod.Source)
+				if err != nil {
+					return nil, errors.E(err, "evaluating symlinks in %q", mod.Source)
+				}
+				// we normalize local paths as relative to the module.
+				// so this is compatible with Terraform module sources.
+				rel, err := filepath.Rel(cfgOpts.WorkingDir, src)
+				if err != nil {
+					return nil, errors.E(err, "normalizing local path %q", mod.Source)
+				}
+				mod.Source = rel
+			}
+		}
 		for _, path := range mod.DependsOn {
 			dependsOn[path] = struct{}{}
 		}

tg/tg_module_test.go

@@ -450,10 +450,74 @@ func TestTerragruntScanModules(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "local module directory also tracked as dependency",
+			layout: []string{
+				`f:some/dir/terragrunt.hcl:` + Doc(
+					Block("terraform",
+						Str("source", "${get_repo_root()}/modules/some"),
+					),
+					Block("include",
+						Labels("root"),
+						Expr("path", `find_in_parent_folders()`),
+					),
+					Block("dependency",
+						Labels("other2"), // other2 declared before other: result must be sorted.
+						Str("config_path", "../other2/dir"),
+					),
+					Block("dependency",
+						Labels("other"),
+						Str("config_path", "../other/dir"),
+					),
+				).String(),
+				`f:modules/some/main.tf:# empty file`,
+				`f:some/other/dir/terragrunt.hcl:` + Doc(
+					Bool("skip", true),
+					Block("terraform",
+						Str("source", "https://some.etc/prj"),
+					)).String(),
+				`f:some/other2/dir/terragrunt.hcl:` + Block("terraform",
+					Str("source", "https://some.etc/prj"),
+				).String(),
+				`f:terragrunt.hcl:` + Doc(
+					Block("terraform"),
+				).String(),
+				`f:common.tfvars:a = "1"`,
+				`f:regional.tfvars:b = "2"`,
+			},
+			want: want{
+				modules: tg.Modules{
+					{
+						Path:       project.NewPath("/some/dir"),
+						Source:     "../../modules/some",
+						ConfigFile: project.NewPath("/some/dir/terragrunt.hcl"),
+						DependsOn: project.Paths{
+							project.NewPath("/some/other/dir"),
+							project.NewPath("/some/other2/dir"),
+							project.NewPath("/terragrunt.hcl"),
+						},
+						After: project.Paths{
+							project.NewPath("/some/other/dir"),
+							project.NewPath("/some/other2/dir"),
+						},
+					},
+					{
+						Path:       project.NewPath("/some/other/dir"),
+						Source:     "https://some.etc/prj",
+						ConfigFile: project.NewPath("/some/other/dir/terragrunt.hcl"),
+					},
+					{
+						Path:       project.NewPath("/some/other2/dir"),
+						Source:     "https://some.etc/prj",
+						ConfigFile: project.NewPath("/some/other2/dir/terragrunt.hcl"),
+					},
+				},
+			},
+		},
 	} {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
-			s := sandbox.NoGit(t, false)
+			s := sandbox.New(t)
 			s.BuildTree(tc.layout)
 			basedir := tc.basedir
 			if basedir.String() == "" {