Address copilot review comments

Signed-off-by: Aravindhan Ayyanathan <aravindhan.a@est.tech>

Author: aravindtga

go/fn/internal/docs/render.go

@@ -40,29 +40,42 @@ type DocOutput struct {
 // RenderHelp writes formatted help text to w.
 // If sections are empty and metadata is zero-value, writes a minimal
 // "no documentation available" message.
-func RenderHelp(w io.Writer, sections Sections, meta Metadata) {
+// Returns the first write error encountered.
+func RenderHelp(w io.Writer, sections Sections, meta Metadata) error {
 	if sections.Short == "" && sections.Long == "" && sections.Examples == "" && isMetadataEmpty(meta) {
-		_, _ = fmt.Fprint(w, "No documentation available. Pass fn.WithDocs to fn.AsMain to enable --help.\n")
-		return
+		_, err := fmt.Fprint(w, "No documentation available. Pass fn.WithDocs to fn.AsMain to enable --help.\n")
+		return err
 	}
 
 	if sections.Short != "" {
-		_, _ = fmt.Fprintf(w, "%s\n", sections.Short)
+		if _, err := fmt.Fprintf(w, "%s\n", sections.Short); err != nil {
+			return err
+		}
 	}
 
 	if sections.Long != "" {
 		if sections.Short != "" {
-			_, _ = fmt.Fprint(w, "\n")
+			if _, err := fmt.Fprint(w, "\n"); err != nil {
+				return err
+			}
+		}
+		if _, err := fmt.Fprintf(w, "%s\n", sections.Long); err != nil {
+			return err
 		}
-		_, _ = fmt.Fprintf(w, "%s\n", sections.Long)
 	}
 
 	if sections.Examples != "" {
 		if sections.Short != "" || sections.Long != "" {
-			_, _ = fmt.Fprint(w, "\n")
+			if _, err := fmt.Fprint(w, "\n"); err != nil {
+				return err
+			}
+		}
+		if _, err := fmt.Fprintf(w, "Examples:\n%s\n", sections.Examples); err != nil {
+			return err
 		}
-		_, _ = fmt.Fprintf(w, "Examples:\n%s\n", sections.Examples)
 	}
+
+	return nil
 }
 
 // isMetadataEmpty reports whether all fields of meta are zero-value.

go/fn/internal/docs/render_test.go

@@ -84,7 +84,9 @@ func TestProperty4_HelpOutputExcludesCobraBoilerplate(t *testing.T) {
 
 		// Render help output.
 		var buf bytes.Buffer
-		RenderHelp(&buf, sections, meta)
+		if err := RenderHelp(&buf, sections, meta); err != nil {
+			t.Errorf("RenderHelp failed: %v", err)
+		}
 		output := buf.String()
 
 		// Assert that the help output does NOT contain cobra-style boilerplate.
@@ -218,7 +220,9 @@ func TestProperty3_HelpOutputContainsParsedSections(t *testing.T) {
 
 		// Render help output.
 		var buf bytes.Buffer
-		RenderHelp(&buf, sections, Metadata{})
+		if err := RenderHelp(&buf, sections, Metadata{}); err != nil {
+			t.Errorf("RenderHelp failed: %v", err)
+		}
 		output := buf.String()
 
 		// Assert that the help output contains each parsed section.
@@ -250,7 +254,9 @@ func TestRenderHelp_FullSectionsAndMetadata(t *testing.T) {
 	}
 
 	var buf bytes.Buffer
-	RenderHelp(&buf, sections, meta)
+	if err := RenderHelp(&buf, sections, meta); err != nil {
+		t.Errorf("RenderHelp failed: %v", err)
+	}
 	output := buf.String()
 
 	// Verify output contains the Short description.
@@ -283,7 +289,9 @@ func TestRenderHelp_EmptySections(t *testing.T) {
 	meta := Metadata{}
 
 	var buf bytes.Buffer
-	RenderHelp(&buf, sections, meta)
+	if err := RenderHelp(&buf, sections, meta); err != nil {
+		t.Errorf("RenderHelp failed: %v", err)
+	}
 	output := buf.String()
 
 	expected := "No documentation available. Pass fn.WithDocs to fn.AsMain to enable --help.\n"

go/fn/run.go

@@ -142,8 +142,8 @@ func AsMain(input any, opts ...Option) error {
 // handleHelp renders help text to STDOUT based on registered docs.
 func handleHelp(cfg *mainConfig) error {
 	if cfg.readme == nil && cfg.metadata == nil {
-		_, _ = fmt.Fprint(os.Stdout, "No documentation available. Pass fn.WithDocs to fn.AsMain to enable --help.\n")
-		return nil
+		_, err := fmt.Fprint(os.Stdout, "No documentation available. Pass fn.WithDocs to fn.AsMain to enable --help.\n")
+		return err
 	}
 
 	sections := docs.ParseMarkers(cfg.readme)
@@ -153,15 +153,14 @@ func handleHelp(cfg *mainConfig) error {
 		meta = docs.Metadata{}
 	}
 
-	docs.RenderHelp(os.Stdout, sections, meta)
-	return nil
+	return docs.RenderHelp(os.Stdout, sections, meta)
 }
 
 // handleDoc renders JSON documentation to STDOUT based on registered docs.
 func handleDoc(cfg *mainConfig) error {
 	if cfg.readme == nil && cfg.metadata == nil {
-		_, _ = fmt.Fprint(os.Stdout, "{}")
-		return nil
+		_, err := fmt.Fprint(os.Stdout, "{}")
+		return err
 	}
 
 	sections := docs.ParseMarkers(cfg.readme)
@@ -184,20 +183,21 @@ func readFilesAsResourceList(paths []string) (*ResourceList, error) {
 		FunctionConfig: NewEmptyKubeObject(),
 	}
 	for _, path := range paths {
-		data, err := os.ReadFile(filepath.Clean(path))
+		cleanPath := filepath.Clean(path)
+		data, err := os.ReadFile(cleanPath)
 		if err != nil {
 			if os.IsNotExist(err) {
-				return nil, fmt.Errorf("file not found: %s", path)
+				return nil, fmt.Errorf("file not found: %s", cleanPath)
 			}
-			return nil, fmt.Errorf("failed to read file %s: %v", path, err)
+			return nil, fmt.Errorf("failed to read file %s: %v", cleanPath, err)
 		}
 		// Empty files are valid — proceed with no items from this file.
 		if len(strings.TrimSpace(string(data))) == 0 {
 			continue
 		}
 		objects, err := ParseKubeObjects(data)
 		if err != nil {
-			return nil, fmt.Errorf("failed to parse KRM resources from %s: %v", path, err)
+			return nil, fmt.Errorf("failed to parse KRM resources from %s: %v", cleanPath, err)
 		}
 		for _, obj := range objects {
 			rl.Items = append(rl.Items, obj)

go/fn/run_filemode_property_test.go

@@ -38,7 +38,9 @@ func genKRMResource() *rapid.Generator[string] {
 		for i := range numEntries {
 			key := rapid.StringMatching(`[a-z][a-z0-9]{1,8}`).Draw(t, fmt.Sprintf("key%d", i))
 			value := rapid.StringMatching(`[a-zA-Z0-9]{1,15}`).Draw(t, fmt.Sprintf("value%d", i))
-			fmt.Fprintf(&dataLines, "  %s: %s\n", key, value)
+			if _, err := fmt.Fprintf(&dataLines, "  %s: %s\n", key, value); err != nil {
+				t.Fatalf("failed to write data line: %v", err)
+			}
 		}
 		return fmt.Sprintf(`apiVersion: v1
 kind: ConfigMap

go/fn/run_flags_test.go

@@ -44,13 +44,13 @@ func captureStdout(t *testing.T, fn func()) string {
 
 	fn()
 
-	_ = w.Close()
+	require.NoError(t, w.Close())
 	os.Stdout = origStdout
 
 	var buf bytes.Buffer
 	_, err = io.Copy(&buf, r)
 	require.NoError(t, err)
-	_ = r.Close()
+	require.NoError(t, r.Close())
 
 	return buf.String()
 }
@@ -66,13 +66,13 @@ func captureStderr(t *testing.T, fn func()) string {
 
 	fn()
 
-	_ = w.Close()
+	require.NoError(t, w.Close())
 	os.Stderr = origStderr
 
 	var buf bytes.Buffer
 	_, err = io.Copy(&buf, r)
 	require.NoError(t, err)
-	_ = r.Close()
+	require.NoError(t, r.Close())
 
 	return buf.String()
 }
@@ -96,11 +96,11 @@ func TestAsMain_HelpFlag_ExitsZero(t *testing.T) {
 	origStdin := os.Stdin
 	r, w, err := os.Pipe()
 	require.NoError(t, err)
-	_ = w.Close() // Close write end immediately — reading would get EOF
+	require.NoError(t, w.Close()) // Close write end immediately — reading would get EOF
 	os.Stdin = r
 	t.Cleanup(func() {
 		os.Stdin = origStdin
-		_ = r.Close()
+		require.NoError(t, r.Close())
 	})
 
 	output := captureStdout(t, func() {