Only treat files with .tmpl extension as templates (#594)

## Changes
In a world before this PR, all files would be treated as `go text
templates`, making the content in these files quake in fear since they
would be executed (as a template).

This PR makes it so that only files with the `.tmpl` extension are
understood to be templates. This is useful for avoiding ambiguity in
cases like where a binary file could be interpreted as a go text
template otherwise.

In order to do so, we introduce the `copyFile` struct which does a copy
of the source file from the template without loading it into memory.

## Tests
Unit tests

libs/template/file.go

@@ -0,0 +1,101 @@
+package template
+
+import (
+	"context"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	"github.com/databricks/cli/libs/filer"
+)
+
+// Interface representing a file to be materialized from a template into a project
+// instance
+type file interface {
+	// Destination path for file. This is where the file will be created when
+	// PersistToDisk is called.
+	DstPath() *destinationPath
+
+	// Write file to disk at the destination path.
+	PersistToDisk() error
+}
+
+type destinationPath struct {
+	// Root path for the project instance. This path uses the system's default
+	// file separator. For example /foo/bar on Unix and C:\foo\bar on windows
+	root string
+
+	// Unix like file path relative to the "root" of the instantiated project. Is used to
+	// evaluate whether the file should be skipped by comparing it to a list of
+	// skip glob patterns.
+	relPath string
+}
+
+// Absolute path of the file, in the os native format. For example /foo/bar on
+// Unix and C:\foo\bar on windows
+func (f *destinationPath) absPath() string {
+	return filepath.Join(f.root, filepath.FromSlash(f.relPath))
+}
+
+type copyFile struct {
+	ctx context.Context
+
+	// Permissions bits for the destination file
+	perm fs.FileMode
+
+	dstPath *destinationPath
+
+	// Filer rooted at template root. Used to read srcPath.
+	srcFiler filer.Filer
+
+	// Relative path from template root for file to be copied.
+	srcPath string
+}
+
+func (f *copyFile) DstPath() *destinationPath {
+	return f.dstPath
+}
+
+func (f *copyFile) PersistToDisk() error {
+	path := f.DstPath().absPath()
+	err := os.MkdirAll(filepath.Dir(path), 0755)
+	if err != nil {
+		return err
+	}
+	srcFile, err := f.srcFiler.Read(f.ctx, f.srcPath)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+	dstFile, err := os.OpenFile(path, os.O_CREATE|os.O_EXCL|os.O_WRONLY, f.perm)
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+	_, err = io.Copy(dstFile, srcFile)
+	return err
+}
+
+type inMemoryFile struct {
+	dstPath *destinationPath
+
+	content []byte
+
+	// Permissions bits for the destination file
+	perm fs.FileMode
+}
+
+func (f *inMemoryFile) DstPath() *destinationPath {
+	return f.dstPath
+}
+
+func (f *inMemoryFile) PersistToDisk() error {
+	path := f.DstPath().absPath()
+
+	err := os.MkdirAll(filepath.Dir(path), 0755)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, f.content, f.perm)
+}

libs/template/file_test.go

@@ -0,0 +1,111 @@
+package template
+
+import (
+	"context"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/databricks/cli/libs/filer"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func testInMemoryFile(t *testing.T, perm fs.FileMode) {
+	tmpDir := t.TempDir()
+
+	f := &inMemoryFile{
+		dstPath: &destinationPath{
+			root:    tmpDir,
+			relPath: "a/b/c",
+		},
+		perm:    perm,
+		content: []byte("123"),
+	}
+	err := f.PersistToDisk()
+	assert.NoError(t, err)
+
+	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "123")
+	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), perm)
+}
+
+func testCopyFile(t *testing.T, perm fs.FileMode) {
+	tmpDir := t.TempDir()
+
+	templateFiler, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(tmpDir, "source"), []byte("qwerty"), perm)
+	require.NoError(t, err)
+
+	f := &copyFile{
+		ctx: context.Background(),
+		dstPath: &destinationPath{
+			root:    tmpDir,
+			relPath: "a/b/c",
+		},
+		perm:     perm,
+		srcPath:  "source",
+		srcFiler: templateFiler,
+	}
+	err = f.PersistToDisk()
+	assert.NoError(t, err)
+
+	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "qwerty")
+	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), perm)
+}
+
+func TestTemplateFileDestinationPath(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.SkipNow()
+	}
+	f := &destinationPath{
+		root:    `a/b/c`,
+		relPath: "d/e",
+	}
+	assert.Equal(t, `a/b/c/d/e`, f.absPath())
+}
+
+func TestTemplateFileDestinationPathForWindows(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+	f := &destinationPath{
+		root:    `c:\a\b\c`,
+		relPath: "d/e",
+	}
+	assert.Equal(t, `c:\a\b\c\d\e`, f.absPath())
+}
+
+func TestTemplateInMemoryFilePersistToDisk(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.SkipNow()
+	}
+	testInMemoryFile(t, 0755)
+}
+
+func TestTemplateInMemoryFilePersistToDiskForWindows(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+	// we have separate tests for windows because of differences in valid
+	// fs.FileMode values we can use for different operating systems.
+	testInMemoryFile(t, 0666)
+}
+
+func TestTemplateCopyFilePersistToDisk(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.SkipNow()
+	}
+	testCopyFile(t, 0644)
+}
+
+func TestTemplateCopyFilePersistToDiskForWindows(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+	// we have separate tests for windows because of differences in valid
+	// fs.FileMode values we can use for different operating systems.
+	testCopyFile(t, 0666)
+}

libs/template/helpers_test.go

@@ -20,7 +20,7 @@ func TestTemplatePrintStringWithoutProcessing(t *testing.T) {
 	assert.NoError(t, err)
 
 	assert.Len(t, r.files, 1)
-	cleanContent := strings.Trim(string(r.files[0].content), "\n\r")
+	cleanContent := strings.Trim(string(r.files[0].(*inMemoryFile).content), "\n\r")
 	assert.Equal(t, `{{ fail "abc" }}`, cleanContent)
 }
 
@@ -35,7 +35,7 @@ func TestTemplateRegexpCompileFunction(t *testing.T) {
 	assert.NoError(t, err)
 
 	assert.Len(t, r.files, 1)
-	content := string(r.files[0].content)
+	content := string(r.files[0].(*inMemoryFile).content)
 	assert.Contains(t, content, "0:food")
 	assert.Contains(t, content, "1:fool")
 }
@@ -52,5 +52,5 @@ func TestTemplateUrlFunction(t *testing.T) {
 	assert.NoError(t, err)
 
 	assert.Len(t, r.files, 1)
-	assert.Equal(t, "https://www.databricks.com", string(r.files[0].content))
+	assert.Equal(t, "https://www.databricks.com", string(r.files[0].(*inMemoryFile).content))
 }

libs/template/renderer.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/fs"
 	"os"
 	"path"
 	"path/filepath"
@@ -18,32 +17,7 @@ import (
 	"golang.org/x/exp/slices"
 )
 
-type inMemoryFile struct {
-	// Root path for the project instance. This path uses the system's default
-	// file separator. For example /foo/bar on Unix and C:\foo\bar on windows
-	root string
-
-	// Unix like relPath for the file (using '/' as the separator). This path
-	// is relative to the root. Using unix like relative paths enables skip patterns
-	// to work across both windows and unix based operating systems.
-	relPath string
-	content []byte
-	perm    fs.FileMode
-}
-
-func (f *inMemoryFile) fullPath() string {
-	return filepath.Join(f.root, filepath.FromSlash(f.relPath))
-}
-
-func (f *inMemoryFile) persistToDisk() error {
-	path := f.fullPath()
-
-	err := os.MkdirAll(filepath.Dir(path), 0755)
-	if err != nil {
-		return err
-	}
-	return os.WriteFile(path, f.content, f.perm)
-}
+const templateExtension = ".tmpl"
 
 // Renders a databricks template as a project
 type renderer struct {
@@ -60,7 +34,7 @@ type renderer struct {
 	baseTemplate *template.Template
 
 	// List of in memory files generated from template
-	files []*inMemoryFile
+	files []file
 
 	// Glob patterns for files and directories to skip. There are three possible
 	// outcomes for skip:
@@ -111,7 +85,7 @@ func newRenderer(ctx context.Context, config map[string]any, templateRoot, libra
 		ctx:           ctx,
 		config:        config,
 		baseTemplate:  tmpl,
-		files:         make([]*inMemoryFile, 0),
+		files:         make([]file, 0),
 		skipPatterns:  make([]string, 0),
 		templateFiler: templateFiler,
 		instanceRoot:  instanceRoot,
@@ -142,17 +116,7 @@ func (r *renderer) executeTemplate(templateDefinition string) (string, error) {
 	return result.String(), nil
 }
 
-func (r *renderer) computeFile(relPathTemplate string) (*inMemoryFile, error) {
-	// read template file contents
-	templateReader, err := r.templateFiler.Read(r.ctx, relPathTemplate)
-	if err != nil {
-		return nil, err
-	}
-	contentTemplate, err := io.ReadAll(templateReader)
-	if err != nil {
-		return nil, err
-	}
-
+func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	// read file permissions
 	info, err := r.templateFiler.Stat(r.ctx, relPathTemplate)
 	if err != nil {
@@ -160,7 +124,33 @@ func (r *renderer) computeFile(relPathTemplate string) (*inMemoryFile, error) {
 	}
 	perm := info.Mode().Perm()
 
+	// If file name does not specify the `.tmpl` extension, then it is copied
+	// over as is, without treating it as a template
+	if !strings.HasSuffix(relPathTemplate, templateExtension) {
+		return &copyFile{
+			dstPath: &destinationPath{
+				root:    r.instanceRoot,
+				relPath: relPathTemplate,
+			},
+			perm:     perm,
+			ctx:      r.ctx,
+			srcPath:  relPathTemplate,
+			srcFiler: r.templateFiler,
+		}, nil
+	}
+
+	// read template file's content
+	templateReader, err := r.templateFiler.Read(r.ctx, relPathTemplate)
+	if err != nil {
+		return nil, err
+	}
+	defer templateReader.Close()
+
 	// execute the contents of the file as a template
+	contentTemplate, err := io.ReadAll(templateReader)
+	if err != nil {
+		return nil, err
+	}
 	content, err := r.executeTemplate(string(contentTemplate))
 	// Capture errors caused by the "fail" helper function
 	if target := (&ErrFail{}); errors.As(err, target) {
@@ -171,16 +161,19 @@ func (r *renderer) computeFile(relPathTemplate string) (*inMemoryFile, error) {
 	}
 
 	// Execute relative path template to get materialized path for the file
+	relPathTemplate = strings.TrimSuffix(relPathTemplate, templateExtension)
 	relPath, err := r.executeTemplate(relPathTemplate)
 	if err != nil {
 		return nil, err
 	}
 
 	return &inMemoryFile{
+		dstPath: &destinationPath{
 			root:    r.instanceRoot,
 			relPath: relPath,
-		content: []byte(content),
+		},
 		perm:    perm,
+		content: []byte(content),
 	}, nil
 }
 
@@ -206,11 +199,11 @@ func (r *renderer) walk() error {
 		if err != nil {
 			return err
 		}
-		isSkipped, err := r.isSkipped(instanceDirectory)
+		match, err := isSkipped(instanceDirectory, r.skipPatterns)
 		if err != nil {
 			return err
 		}
-		if isSkipped {
+		if match {
 			logger.Infof(r.ctx, "skipping directory: %s", instanceDirectory)
 			continue
 		}
@@ -255,7 +248,7 @@ func (r *renderer) walk() error {
 			if err != nil {
 				return err
 			}
-			logger.Infof(r.ctx, "added file to list of in memory files: %s", f.relPath)
+			logger.Infof(r.ctx, "added file to list of possible project files: %s", f.DstPath().relPath)
 			r.files = append(r.files, f)
 		}
 
@@ -266,14 +259,14 @@ func (r *renderer) walk() error {
 func (r *renderer) persistToDisk() error {
 	// Accumulate files which we will persist, skipping files whose path matches
 	// any of the skip patterns
-	filesToPersist := make([]*inMemoryFile, 0)
+	filesToPersist := make([]file, 0)
 	for _, file := range r.files {
-		isSkipped, err := r.isSkipped(file.relPath)
+		match, err := isSkipped(file.DstPath().relPath, r.skipPatterns)
 		if err != nil {
 			return err
 		}
-		if isSkipped {
-			log.Infof(r.ctx, "skipping file: %s", file.relPath)
+		if match {
+			log.Infof(r.ctx, "skipping file: %s", file.DstPath())
 			continue
 		}
 		filesToPersist = append(filesToPersist, file)
@@ -281,7 +274,7 @@ func (r *renderer) persistToDisk() error {
 
 	// Assert no conflicting files exist
 	for _, file := range filesToPersist {
-		path := file.fullPath()
+		path := file.DstPath().absPath()
 		_, err := os.Stat(path)
 		if err == nil {
 			return fmt.Errorf("failed to persist to disk, conflict with existing file: %s", path)
@@ -293,7 +286,7 @@ func (r *renderer) persistToDisk() error {
 
 	// Persist files to disk
 	for _, file := range filesToPersist {
-		err := file.persistToDisk()
+		err := file.PersistToDisk()
 		if err != nil {
 			return err
 		}
@@ -301,8 +294,8 @@ func (r *renderer) persistToDisk() error {
 	return nil
 }
 
-func (r *renderer) isSkipped(filePath string) (bool, error) {
-	for _, pattern := range r.skipPatterns {
+func isSkipped(filePath string, patterns []string) (bool, error) {
+	for _, pattern := range patterns {
 		isMatch, err := path.Match(pattern, filePath)
 		if err != nil {
 			return false, err

libs/template/renderer_test.go

@@ -3,6 +3,7 @@ package template
 import (
 	"context"
 	"fmt"
+	"io"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -89,59 +90,58 @@ My email is {{template "email"}}
 }
 
 func TestRendererIsSkipped(t *testing.T) {
-	r := renderer{
-		skipPatterns: []string{"a*", "*yz", "def", "a/b/*"},
-	}
+
+	skipPatterns := []string{"a*", "*yz", "def", "a/b/*"}
 
 	// skipped paths
-	isSkipped, err := r.isSkipped("abc")
+	match, err := isSkipped("abc", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
-	isSkipped, err = r.isSkipped("abcd")
+	match, err = isSkipped("abcd", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
-	isSkipped, err = r.isSkipped("a")
+	match, err = isSkipped("a", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
-	isSkipped, err = r.isSkipped("xxyz")
+	match, err = isSkipped("xxyz", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
-	isSkipped, err = r.isSkipped("yz")
+	match, err = isSkipped("yz", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
-	isSkipped, err = r.isSkipped("a/b/c")
+	match, err = isSkipped("a/b/c", skipPatterns)
 	require.NoError(t, err)
-	assert.True(t, isSkipped)
+	assert.True(t, match)
 
 	// NOT skipped paths
-	isSkipped, err = r.isSkipped(".")
+	match, err = isSkipped(".", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 
-	isSkipped, err = r.isSkipped("y")
+	match, err = isSkipped("y", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 
-	isSkipped, err = r.isSkipped("z")
+	match, err = isSkipped("z", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 
-	isSkipped, err = r.isSkipped("defg")
+	match, err = isSkipped("defg", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 
-	isSkipped, err = r.isSkipped("cat")
+	match, err = isSkipped("cat", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 
-	isSkipped, err = r.isSkipped("a/b/c/d")
+	match, err = isSkipped("a/b/c/d", skipPatterns)
 	require.NoError(t, err)
-	assert.False(t, isSkipped)
+	assert.False(t, match)
 }
 
 func TestRendererPersistToDisk(t *testing.T) {
@@ -152,30 +152,38 @@ func TestRendererPersistToDisk(t *testing.T) {
 		ctx:          ctx,
 		instanceRoot: tmpDir,
 		skipPatterns: []string{"a/b/c", "mn*"},
-		files: []*inMemoryFile{
-			{
+		files: []file{
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "a/b/c",
-				content: nil,
-				perm:    0444,
 				},
-			{
+				perm:    0444,
+				content: nil,
+			},
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "mno",
-				content: nil,
-				perm:    0444,
 				},
-			{
+				perm:    0444,
+				content: nil,
+			},
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "a/b/d",
-				content: []byte("123"),
-				perm:    0444,
 				},
-			{
+				perm:    0444,
+				content: []byte("123"),
+			},
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "mmnn",
-				content: []byte("456"),
+				},
 				perm:    0444,
+				content: []byte("456"),
 			},
 		},
 	}
@@ -204,8 +212,20 @@ func TestRendererWalk(t *testing.T) {
 
 	getContent := func(r *renderer, path string) string {
 		for _, f := range r.files {
-			if f.relPath == path {
-				return strings.Trim(string(f.content), "\r\n")
+			if f.DstPath().relPath != path {
+				continue
+			}
+			switch v := f.(type) {
+			case *inMemoryFile:
+				return strings.Trim(string(v.content), "\r\n")
+			case *copyFile:
+				r, err := r.templateFiler.Read(context.Background(), v.srcPath)
+				require.NoError(t, err)
+				b, err := io.ReadAll(r)
+				require.NoError(t, err)
+				return strings.Trim(string(b), "\r\n")
+			default:
+				require.FailNow(t, "execution should not reach here")
 			}
 		}
 		require.FailNow(t, "file is absent: "+path)
@@ -241,7 +261,7 @@ func TestRendererSkipsDirsEagerly(t *testing.T) {
 	assert.NoError(t, err)
 
 	assert.Len(t, r.files, 1)
-	content := string(r.files[0].content)
+	content := string(r.files[0].(*inMemoryFile).content)
 	assert.Equal(t, "I should be the only file created", strings.Trim(content, "\r\n"))
 }
 
@@ -309,55 +329,6 @@ func TestRendererSkip(t *testing.T) {
 	assert.NoFileExists(t, filepath.Join(tmpDir, "dir2/file6"))
 }
 
-func TestRendererInMemoryFileFullPathForWindows(t *testing.T) {
-	if runtime.GOOS != "windows" {
-		t.SkipNow()
-	}
-	f := &inMemoryFile{
-		root:    `c:\a\b\c`,
-		relPath: "d/e",
-	}
-	assert.Equal(t, `c:\a\b\c\d\e`, f.fullPath())
-}
-
-func TestRendererInMemoryFilePersistToDiskSetsExecutableBit(t *testing.T) {
-	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
-		t.SkipNow()
-	}
-	tmpDir := t.TempDir()
-
-	f := &inMemoryFile{
-		root:    tmpDir,
-		relPath: "a/b/c",
-		content: []byte("123"),
-		perm:    0755,
-	}
-	err := f.persistToDisk()
-	assert.NoError(t, err)
-
-	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "123")
-	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), 0755)
-}
-
-func TestRendererInMemoryFilePersistToDiskForWindows(t *testing.T) {
-	if runtime.GOOS != "windows" {
-		t.SkipNow()
-	}
-	tmpDir := t.TempDir()
-
-	f := &inMemoryFile{
-		root:    tmpDir,
-		relPath: "a/b/c",
-		content: []byte("123"),
-		perm:    0666,
-	}
-	err := f.persistToDisk()
-	assert.NoError(t, err)
-
-	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "123")
-	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), 0666)
-}
-
 func TestRendererReadsPermissionsBits(t *testing.T) {
 	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
 		t.SkipNow()
@@ -373,8 +344,16 @@ func TestRendererReadsPermissionsBits(t *testing.T) {
 
 	getPermissions := func(r *renderer, path string) fs.FileMode {
 		for _, f := range r.files {
-			if f.relPath == path {
-				return f.perm
+			if f.DstPath().relPath != path {
+				continue
+			}
+			switch v := f.(type) {
+			case *inMemoryFile:
+				return v.perm
+			case *copyFile:
+				return v.perm
+			default:
+				require.FailNow(t, "execution should not reach here")
 			}
 		}
 		require.FailNow(t, "file is absent: "+path)
@@ -396,12 +375,14 @@ func TestRendererErrorOnConflictingFile(t *testing.T) {
 
 	r := renderer{
 		skipPatterns: []string{},
-		files: []*inMemoryFile{
-			{
+		files: []file{
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "a",
-				content: []byte("123"),
+				},
 				perm:    0444,
+				content: []byte("123"),
 			},
 		},
 	}
@@ -421,12 +402,14 @@ func TestRendererNoErrorOnConflictingFileIfSkipped(t *testing.T) {
 	r := renderer{
 		ctx:          ctx,
 		skipPatterns: []string{"a"},
-		files: []*inMemoryFile{
-			{
+		files: []file{
+			&inMemoryFile{
+				dstPath: &destinationPath{
 					root:    tmpDir,
 					relPath: "a",
-				content: []byte("123"),
+				},
 				perm:    0444,
+				content: []byte("123"),
 			},
 		},
 	}
@@ -436,3 +419,18 @@ func TestRendererNoErrorOnConflictingFileIfSkipped(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, r.files, 1)
 }
+
+func TestRendererNonTemplatesAreCreatedAsCopyFiles(t *testing.T) {
+	ctx := context.Background()
+	tmpDir := t.TempDir()
+
+	r, err := newRenderer(ctx, nil, "./testdata/copy-file-walk/template", "./testdata/copy-file-walk/library", tmpDir)
+	require.NoError(t, err)
+
+	err = r.walk()
+	assert.NoError(t, err)
+
+	assert.Len(t, r.files, 1)
+	assert.Equal(t, r.files[0].(*copyFile).srcPath, "not-a-template")
+	assert.Equal(t, r.files[0].DstPath().absPath(), filepath.Join(tmpDir, "not-a-template"))
+}

libs/template/testdata/copy-file-walk/template/not-a-template

@@ -0,0 +1 @@
+abc