Execute paths without the .tmpl extension as templates (#654)

## Changes
The `.tmpl` extension is only meant as a qualifier for whether the file
content is executed as a template. All file paths in the `template`
directory should be treated as valid go text templates.

Before only paths with the `.tmpl` extensions would be resolved as
templates, after this change, all file paths are interpreted as
templates.

## Tests
Unit test. The newly added unit tests also asserts that the file path is
correct, even when the `.tmpl` extension is missing.

Author: shreyas-goenka

libs/template/renderer.go

@@ -124,19 +124,29 @@ func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	}
 	perm := info.Mode().Perm()
 
+	// Execute relative path template to get destination path for the file
+	relPath, err := r.executeTemplate(relPathTemplate)
+	if err != nil {
+		return nil, err
+	}
+
 	// 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,
+				relPath: relPath,
 			},
 			perm:     perm,
 			ctx:      r.ctx,
 			srcPath:  relPathTemplate,
 			srcFiler: r.templateFiler,
 		}, nil
+	} else {
+		// Trim the .tmpl suffix from file name, if specified in the template
+		// path
+		relPath = strings.TrimSuffix(relPath, templateExtension)
 	}
 
 	// read template file's content
@@ -160,13 +170,6 @@ func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 		return nil, fmt.Errorf("failed to compute file content for %s. %w", relPathTemplate, err)
 	}
 
-	// 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,

libs/template/renderer_test.go

@@ -459,3 +459,17 @@ func TestRendererFileTreeRendering(t *testing.T) {
 	assert.DirExists(t, filepath.Join(tmpDir, "my_directory"))
 	assert.FileExists(t, filepath.Join(tmpDir, "my_directory", "my_file"))
 }
+
+func TestRendererSubTemplateInPath(t *testing.T) {
+	ctx := context.Background()
+	tmpDir := t.TempDir()
+
+	r, err := newRenderer(ctx, nil, "./testdata/template-in-path/template", "./testdata/template-in-path/library", tmpDir)
+	require.NoError(t, err)
+
+	err = r.walk()
+	require.NoError(t, err)
+
+	assert.Equal(t, filepath.Join(tmpDir, "my_directory", "my_file"), r.files[0].DstPath().absPath())
+	assert.Equal(t, "my_directory/my_file", r.files[0].DstPath().relPath)
+}

libs/template/testdata/template-in-path/library/my_funcs.tmpl

@@ -0,0 +1,7 @@
+{{define "dir_name" -}}
+my_directory
+{{- end}}
+
+{{define "file_name" -}}
+my_file
+{{- end}}