Add file paths to error messages (#173)

* Initial plan

* Add file paths to error messages for better debugging

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Alex Collins <alexec@users.noreply.github.com>
Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Author: Copilot

pkg/codingcontext/context.go

@@ -167,7 +167,7 @@ func (cc *Context) findTask(taskName string) error {
 				if shouldExpandParams(frontMatter.ExpandParams) {
 					textContent, err = cc.expandParams(textContent, nil)
 					if err != nil {
-						return fmt.Errorf("failed to expand parameters: %w", err)
+						return fmt.Errorf("failed to expand parameters in task file %s: %w", path, err)
 					}
 				}
 				finalContent.WriteString(textContent)
@@ -231,7 +231,7 @@ func (cc *Context) findCommand(commandName string, params taskparser.Params) (st
 		if shouldExpandParams(frontMatter.ExpandParams) {
 			processedContent, err = cc.expandParams(md.Content, params)
 			if err != nil {
-				return fmt.Errorf("failed to expand parameters: %w", err)
+				return fmt.Errorf("failed to expand parameters in command file %s: %w", path, err)
 			}
 		} else {
 			processedContent = md.Content
@@ -475,15 +475,15 @@ func (cc *Context) findExecuteRuleFiles(ctx context.Context, homeDir string) err
 		var frontmatter markdown.RuleFrontMatter
 		md, err := markdown.ParseMarkdownFile(path, &frontmatter)
 		if err != nil {
-			return fmt.Errorf("failed to parse markdown file: %w", err)
+			return fmt.Errorf("failed to parse markdown file %s: %w", path, err)
 		}
 
 		// Expand parameters only if expand is not explicitly set to false
 		var processedContent string
 		if shouldExpandParams(frontmatter.ExpandParams) {
 			processedContent, err = cc.expandParams(md.Content, nil)
 			if err != nil {
-				return fmt.Errorf("failed to expand parameters: %w", err)
+				return fmt.Errorf("failed to expand parameters in file %s: %w", path, err)
 			}
 		} else {
 			processedContent = md.Content

pkg/codingcontext/markdown/markdown.go

@@ -27,7 +27,7 @@ type RuleMarkdown = Markdown[RuleFrontMatter]
 func ParseMarkdownFile[T any](path string, frontMatter *T) (Markdown[T], error) {
 	fh, err := os.Open(path)
 	if err != nil {
-		return Markdown[T]{}, fmt.Errorf("failed to open file: %w", err)
+		return Markdown[T]{}, fmt.Errorf("failed to open file %s: %w", path, err)
 	}
 	defer fh.Close()
 
@@ -68,13 +68,13 @@ func ParseMarkdownFile[T any](path string, frontMatter *T) (Markdown[T], error)
 	}
 
 	if err := s.Err(); err != nil {
-		return Markdown[T]{}, fmt.Errorf("failed to scan file: %w", err)
+		return Markdown[T]{}, fmt.Errorf("failed to scan file %s: %w", path, err)
 	}
 
 	// Parse frontmatter if we collected any
 	if frontMatterBytes.Len() > 0 {
 		if err := yaml.Unmarshal(frontMatterBytes.Bytes(), frontMatter); err != nil {
-			return Markdown[T]{}, fmt.Errorf("failed to unmarshal frontmatter: %w", err)
+			return Markdown[T]{}, fmt.Errorf("failed to unmarshal frontmatter in file %s: %w", path, err)
 		}
 	}
 

pkg/codingcontext/markdown/markdown_test.go

@@ -3,6 +3,7 @@ package markdown
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -101,6 +102,57 @@ func TestParseMarkdownFile_FileNotFound(t *testing.T) {
 	if err == nil {
 		t.Error("ParseMarkdownFile() expected error for non-existent file, got nil")
 	}
+	// Verify error message includes file path
+	if err != nil && !strings.Contains(err.Error(), "/nonexistent/file.md") {
+		t.Errorf("ParseMarkdownFile() error should contain file path, got: %v", err)
+	}
+}
+
+func TestParseMarkdownFile_ErrorsIncludeFilePath(t *testing.T) {
+	tests := []struct {
+		name    string
+		content string
+		want    string // substring that should appear in error
+	}{
+		{
+			name: "invalid YAML in frontmatter",
+			content: `---
+invalid: yaml: : syntax
+---
+Content here`,
+			want: "failed to unmarshal frontmatter in file",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create a temporary file
+			tmpDir := t.TempDir()
+			tmpFile := filepath.Join(tmpDir, "test.md")
+			if err := os.WriteFile(tmpFile, []byte(tt.content), 0o644); err != nil {
+				t.Fatalf("failed to create temp file: %v", err)
+			}
+
+			// Parse the file
+			var frontmatter BaseFrontMatter
+			_, err := ParseMarkdownFile(tmpFile, &frontmatter)
+
+			// Check that we got an error
+			if err == nil {
+				t.Fatalf("ParseMarkdownFile() expected error for %s, got nil", tt.name)
+			}
+
+			// Check that error contains expected substring
+			if !strings.Contains(err.Error(), tt.want) {
+				t.Errorf("ParseMarkdownFile() error should contain %q, got: %v", tt.want, err)
+			}
+
+			// Check that error contains file path
+			if !strings.Contains(err.Error(), tmpFile) {
+				t.Errorf("ParseMarkdownFile() error should contain file path %q, got: %v", tmpFile, err)
+			}
+		})
+	}
 }
 
 func TestParseMarkdownFile_CustomStruct(t *testing.T) {