copyDir: detect if the module install path is a symlink to a directory (#20603)

configs/configload and internal/initwd both had a copyDir function that
would fail if the source directory contained a symlinked directory,
because the os.FileMode.IsDir() returns false for symlinks.

This PR adds a check for a symlink and copies that symlink in the
target directory. It handles symlinks for both files and directories
(with included tests).

Fixes #20539

configs/configload/copy_dir.go

@@ -59,6 +59,17 @@ func copyDir(dst, src string) error {
 			return nil
 		}
 
+		// If the current path is a symlink, recreate the symlink relative to
+		// the dst directory
+		if info.Mode()&os.ModeSymlink == os.ModeSymlink {
+			target, err := os.Readlink(path)
+			if err != nil {
+				return err
+			}
+
+			return os.Symlink(target, dstPath)
+		}
+
 		// If we have a file, copy the contents.
 		srcF, err := os.Open(path)
 		if err != nil {

configs/configload/copy_dir_test.go

@@ -0,0 +1,107 @@
+package configload
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// TestCopyDir_symlinks sets up a directory with two submodules,
+// one being a symlink to the other
+//
+// The resultant file structure is as follows:
+// 	├── modules
+//  │   ├── symlink-module -> test-module
+//  │   └── test-module
+//  │       └── main.tf
+//  └── target
+//     ├── symlink-module -> test-module
+//     └── test-module
+//         └── main.tf
+
+func TestCopyDir_symlinks(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "copy-dir-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	moduleDir := filepath.Join(tmpdir, "modules")
+	err = os.Mkdir(moduleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	subModuleDir := filepath.Join(moduleDir, "test-module")
+	err = os.Mkdir(subModuleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = ioutil.WriteFile(filepath.Join(subModuleDir, "main.tf"), []byte("hello"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Symlink("test-module", filepath.Join(moduleDir, "symlink-module"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	targetDir := filepath.Join(tmpdir, "target")
+	os.Mkdir(targetDir, os.ModePerm)
+
+	err = copyDir(targetDir, moduleDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "test-module", "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target test-module/main.tf was not created")
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "symlink-module", "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target symlink-module/main.tf was not created")
+	}
+}
+
+func TestCopyDir_symlink_file(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "copy-file-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	moduleDir := filepath.Join(tmpdir, "modules")
+	err = os.Mkdir(moduleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = ioutil.WriteFile(filepath.Join(moduleDir, "main.tf"), []byte("hello"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Symlink("main.tf", filepath.Join(moduleDir, "symlink.tf"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	targetDir := filepath.Join(tmpdir, "target")
+	os.Mkdir(targetDir, os.ModePerm)
+
+	err = copyDir(targetDir, moduleDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target/main.tf was not created")
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "symlink.tf")); os.IsNotExist(err) {
+		t.Fatal("target/symlink.tf was not created")
+	}
+}

internal/initwd/copy_dir.go

@@ -59,6 +59,17 @@ func copyDir(dst, src string) error {
 			return nil
 		}
 
+		// If the current path is a symlink, recreate the symlink relative to
+		// the dst directory
+		if info.Mode()&os.ModeSymlink == os.ModeSymlink {
+			target, err := os.Readlink(path)
+			if err != nil {
+				return err
+			}
+
+			return os.Symlink(target, dstPath)
+		}
+
 		// If we have a file, copy the contents.
 		srcF, err := os.Open(path)
 		if err != nil {

internal/initwd/copy_dir_test.go

@@ -0,0 +1,107 @@
+package initwd
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// TestCopyDir_symlinks sets up a directory with two submodules,
+// one being a symlink to the other
+//
+// The resultant file structure is as follows:
+// 	├── modules
+//  │   ├── symlink-module -> test-module
+//  │   └── test-module
+//  │       └── main.tf
+//  └── target
+//     ├── symlink-module -> test-module
+//     └── test-module
+//         └── main.tf
+
+func TestCopyDir_symlinks(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "copy-dir-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	moduleDir := filepath.Join(tmpdir, "modules")
+	err = os.Mkdir(moduleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	subModuleDir := filepath.Join(moduleDir, "test-module")
+	err = os.Mkdir(subModuleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = ioutil.WriteFile(filepath.Join(subModuleDir, "main.tf"), []byte("hello"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Symlink("test-module", filepath.Join(moduleDir, "symlink-module"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	targetDir := filepath.Join(tmpdir, "target")
+	os.Mkdir(targetDir, os.ModePerm)
+
+	err = copyDir(targetDir, moduleDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "test-module", "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target test-module/main.tf was not created")
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "symlink-module", "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target symlink-module/main.tf was not created")
+	}
+}
+
+func TestCopyDir_symlink_file(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "copy-file-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	moduleDir := filepath.Join(tmpdir, "modules")
+	err = os.Mkdir(moduleDir, os.ModePerm)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = ioutil.WriteFile(filepath.Join(moduleDir, "main.tf"), []byte("hello"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Symlink("main.tf", filepath.Join(moduleDir, "symlink.tf"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	targetDir := filepath.Join(tmpdir, "target")
+	os.Mkdir(targetDir, os.ModePerm)
+
+	err = copyDir(targetDir, moduleDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "main.tf")); os.IsNotExist(err) {
+		t.Fatal("target/main.tf was not created")
+	}
+
+	if _, err = os.Lstat(filepath.Join(targetDir, "symlink.tf")); os.IsNotExist(err) {
+		t.Fatal("target/symlink.tf was not created")
+	}
+}