fix: prevent malformed tool diffs from breaking chat

Safely falls back to raw patch text for invalid diffs
Protects individual tool parts from crashing the chat
Covers malformed apply_patch and edit diff cases

packages/ui/src/components/chat/message/parts/ToolPart.tsx

@@ -44,6 +44,7 @@ import { useDurationTickerNow } from './useDurationTicker';
 import { resolveFallbackTaskSessionId } from './resolveFallbackTaskSessionId';
 import { areRenderRelevantPartsEqual } from '../renderCompare';
 import { useI18n } from '@/lib/i18n';
+import { getDiffPatchEntries, getPatchText } from './toolDiffUtils';
 
 const TOOL_ROW_TEXT_CLASS = '!text-[length:var(--text-meta)] !leading-4 sm:!leading-6 tracking-normal';
 const TOOL_ROW_TITLE_CLASS = cn('typography-meta font-medium', TOOL_ROW_TEXT_CLASS);
@@ -308,21 +309,6 @@ const extractFirstChangedLineFromDiff = (diffText: string): number | undefined =
     return firstHunkStart;
 };
 
-const getPatchText = (value: unknown): string | undefined => {
-    if (typeof value === 'string') {
-        return /\S/.test(value) ? value : undefined;
-    }
-
-    if (value && typeof value === 'object') {
-        const patch = (value as { patch?: unknown }).patch;
-        if (typeof patch === 'string') {
-            return /\S/.test(patch) ? patch : undefined;
-        }
-    }
-
-    return undefined;
-};
-
 const buildWritePreviewPatch = (filePath: string | undefined, content: string): string | undefined => {
     const normalizedContent = content.replace(/\r\n/g, '\n');
     if (!normalizedContent.trim()) {
@@ -1298,70 +1284,6 @@ const TOOL_NORMAL_ICON_STYLE: React.CSSProperties = { color: 'var(--tools-icon)'
 const TOOL_ERROR_TITLE_STYLE: React.CSSProperties = { color: 'var(--status-error)' };
 const TOOL_NORMAL_TITLE_STYLE: React.CSSProperties = { color: 'var(--tools-title)' };
 
-type DiffPatchEntry = {
-    id: string;
-    title: string;
-    patch: string;
-};
-
-const hasUnifiedDiffHunk = (patch: string): boolean => /^@@\s+-\d+(?:,\d+)?\s+\+\d+(?:,\d+)?\s+@@/m.test(patch);
-
-const isUnifiedFileHeaderPair = (minusLine: string, plusLine: string): boolean => {
-    if (!minusLine.startsWith('--- ') || !plusLine.startsWith('+++ ')) {
-        return false;
-    }
-
-    const oldPath = minusLine.slice(4).trim();
-    const newPath = plusLine.slice(4).trim();
-    return oldPath.length > 0 && newPath.length > 0;
-};
-
-const getUnifiedDiffPath = (patch: string, fallbackTitle: string): string => {
-    const plusHeader = patch.match(/^\+\+\+\s+(?:[ab]\/(.+)|(.+))$/m);
-    const rawPath = plusHeader?.[1] ?? plusHeader?.[2];
-    if (!rawPath || rawPath === '/dev/null') {
-        return fallbackTitle;
-    }
-    return rawPath;
-};
-
-const splitUnifiedDiffPatch = (patch: string): DiffPatchEntry[] => {
-    const normalized = patch.replace(/\r\n/g, '\n').trim();
-    if (!normalized) {
-        return [];
-    }
-
-    const lines = normalized.split('\n');
-    const starts: number[] = [];
-
-    for (let index = 0; index < lines.length; index += 1) {
-        const line = lines[index] ?? '';
-        const nextLine = lines[index + 1] ?? '';
-        if (line.startsWith('diff --git ') || line.startsWith('Index: ') || isUnifiedFileHeaderPair(line, nextLine)) {
-            starts.push(index);
-        }
-    }
-
-    const chunks = starts.length > 0
-        ? starts.map((start, index) => lines.slice(start, starts[index + 1] ?? lines.length).join('\n').trim())
-        : [normalized];
-
-    return chunks
-        .map((chunk, index) => {
-            if (!hasUnifiedDiffHunk(chunk)) {
-                return null;
-            }
-
-            const title = getUnifiedDiffPath(chunk, `Diff ${index + 1}`);
-            return {
-                id: `${title}-${index}`,
-                title,
-                patch: chunk,
-            } satisfies DiffPatchEntry;
-        })
-        .filter((entry): entry is DiffPatchEntry => entry !== null);
-};
-
 const renderPathLikeGitChanges = (path: string, grow = true) => {
     const lastSlash = path.lastIndexOf('/');
     if (lastSlash === -1) {
@@ -1447,60 +1369,48 @@ const renderAnimatedPathWithIcon = (path: string, animate = true, grow = true, s
     );
 };
 
-const getDiffPatchEntries = (
-    metadata: Record<string, unknown> | undefined,
-    fallbackDiff: string,
-    currentDirectory: string,
-): DiffPatchEntry[] => {
-    const files = Array.isArray(metadata?.files) ? metadata.files : [];
+const PlainDiffFallback: React.FC<{ diff: string }> = ({ diff }) => (
+    <pre
+        className="m-0 overflow-auto whitespace-pre-wrap break-words rounded-lg p-2 typography-code"
+        style={{
+            backgroundColor: 'var(--syntax-base-background)',
+            color: 'var(--syntax-base-foreground)',
+        }}
+    >
+        {diff}
+    </pre>
+);
 
-    const entries = files
-        .map((file, index) => {
-            if (!file || typeof file !== 'object') {
-                return null;
-            }
+class DiffPreviewErrorBoundary extends React.Component<{
+    resetKey: string;
+    fallback: React.ReactNode;
+    children: React.ReactNode;
+}, { hasError: boolean }> {
+    state = { hasError: false };
 
-            const record = file as { relativePath?: unknown; filePath?: unknown; patch?: unknown; diff?: unknown };
-            const patch = getPatchText(record.patch) ?? getPatchText(record.diff) ?? '';
-            const splitPatchEntries = splitUnifiedDiffPatch(patch);
-            if (!patch || splitPatchEntries.length === 0) {
-                return null;
-            }
-
-            const rawPath = typeof record.relativePath === 'string'
-                ? record.relativePath
-                : typeof record.filePath === 'string'
-                    ? record.filePath
-                    : `File ${index + 1}`;
-
-            const title = typeof rawPath === 'string'
-                ? getRelativePath(rawPath, currentDirectory)
-                : `File ${index + 1}`;
-
-            return splitPatchEntries.map((entry, splitIndex) => ({
-                id: `${title}-${index}-${splitIndex}`,
-                title: splitPatchEntries.length === 1 ? title : getRelativePath(entry.title, currentDirectory),
-                patch: entry.patch,
-            } satisfies DiffPatchEntry));
-        })
-        .flat()
-        .filter((entry): entry is DiffPatchEntry => entry !== null);
-
-    if (entries.length > 0) {
-        return entries;
+    static getDerivedStateFromError(): { hasError: boolean } {
+        return { hasError: true };
     }
 
-    const splitEntries = splitUnifiedDiffPatch(fallbackDiff).map((entry) => ({
-        ...entry,
-        title: getRelativePath(entry.title, currentDirectory),
-    }));
-
-    if (splitEntries.length > 0) {
-        return splitEntries;
+    componentDidUpdate(prevProps: { resetKey: string }) {
+        if (prevProps.resetKey !== this.props.resetKey && this.state.hasError) {
+            this.setState({ hasError: false });
+        }
     }
 
-    return [];
-};
+    componentDidCatch(error: Error) {
+        if (process.env.NODE_ENV === 'development') {
+            console.warn('Tool diff preview failed; rendering raw patch instead.', error);
+        }
+    }
+
+    render() {
+        if (this.state.hasError) {
+            return this.props.fallback;
+        }
+        return this.props.children;
+    }
+}
 
 const DiffPreview: React.FC<DiffPreviewProps> = React.memo(({ diff, pierreTheme, pierreThemeType, diffViewMode }) => {
     const options = React.useMemo(
@@ -1520,14 +1430,18 @@ const DiffPreview: React.FC<DiffPreviewProps> = React.memo(({ diff, pierreTheme,
         [diffViewMode, pierreTheme, pierreThemeType]
     );
 
+    const fallback = <PlainDiffFallback diff={diff} />;
+
     return (
         <div className="typography-code px-1 pb-1 pt-0">
-            <PatchDiff
-                patch={diff}
-                metrics={TOOL_DIFF_METRICS}
-                options={options}
-                className="block w-full"
-            />
+            <DiffPreviewErrorBoundary resetKey={diff} fallback={fallback}>
+                <PatchDiff
+                    patch={diff}
+                    metrics={TOOL_DIFF_METRICS}
+                    options={options}
+                    className="block w-full"
+                />
+            </DiffPreviewErrorBoundary>
         </div>
     );
 });
@@ -1559,13 +1473,17 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
     const hasStringOutput = typeof rawOutput === 'string' && rawOutput.length > 0;
     const outputString = typeof rawOutput === 'string' ? rawOutput : '';
 
+    const fileDiff = isRecord(metadata?.filediff) ? metadata.filediff : undefined;
     const diffContent = getPatchText((metadata as { patch?: unknown } | undefined)?.patch)
         ?? getPatchText(metadata?.diff)
+        ?? getPatchText(fileDiff?.patch)
+        ?? getPatchText(fileDiff?.diff)
         ?? null;
     const diffEntries = React.useMemo(
-        () => (diffContent ? getDiffPatchEntries(metadata, diffContent, currentDirectory) : []),
+        () => getDiffPatchEntries(metadata, diffContent ?? undefined, (path) => getRelativePath(path, currentDirectory)),
         [currentDirectory, diffContent, metadata]
     );
+    const hasVisualDiffEntry = diffEntries.some((entry) => entry.renderMode === 'diff');
     const hideToolInputPreview = part.tool === 'apply_patch'
         || part.tool === 'edit'
         || part.tool === 'multiedit';
@@ -1752,12 +1670,16 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
                                     {renderPathLikeGitChanges(entry.title)}
                                 </div>
                             ) : null}
-                            <DiffPreview
-                                diff={entry.patch}
-                                pierreTheme={pierreTheme}
-                                pierreThemeType={pierreThemeType}
-                                diffViewMode={diffViewMode}
-                            />
+                            {entry.renderMode === 'diff' ? (
+                                <DiffPreview
+                                    diff={entry.patch}
+                                    pierreTheme={pierreTheme}
+                                    pierreThemeType={pierreThemeType}
+                                    diffViewMode={diffViewMode}
+                                />
+                            ) : (
+                                <PlainDiffFallback diff={entry.patch} />
+                            )}
                         </div>
                     ))}
                     {renderDiagnosticsSection()}
@@ -1840,7 +1762,7 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
 
                     {state.status === 'completed' && 'output' in state && (
                         <div>
-                            {(part.tool === 'edit' || part.tool === 'multiedit' || part.tool === 'apply_patch' || part.tool === 'write') && diffContent ? (
+                            {(part.tool === 'edit' || part.tool === 'multiedit' || part.tool === 'apply_patch' || part.tool === 'write') && hasVisualDiffEntry ? (
                                 <div className="mb-1 flex items-center justify-end gap-2">
                                     <DiffViewToggle
                                         mode={diffViewMode}
@@ -1873,7 +1795,7 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
 
 ToolExpandedContent.displayName = 'ToolExpandedContent';
 
-const ToolPart: React.FC<ToolPartProps> = ({
+const ToolPartContent: React.FC<ToolPartProps> = ({
     part,
     isExpanded,
     onToggle,
@@ -2831,6 +2753,72 @@ const ToolPart: React.FC<ToolPartProps> = ({
     );
 };
 
+class ToolPartErrorBoundary extends React.Component<{
+    children: React.ReactNode;
+    displayName: string;
+    errorLabel: string;
+    resetKey: unknown;
+    toolName: string;
+}, { hasError: boolean; error?: Error }> {
+    state: { hasError: boolean; error?: Error } = { hasError: false };
+
+    static getDerivedStateFromError(error: Error): { hasError: boolean; error: Error } {
+        return { hasError: true, error };
+    }
+
+    componentDidUpdate(prevProps: { resetKey: unknown }) {
+        if (prevProps.resetKey !== this.props.resetKey && this.state.hasError) {
+            this.setState({ hasError: false, error: undefined });
+        }
+    }
+
+    componentDidCatch(error: Error) {
+        if (process.env.NODE_ENV === 'development') {
+            console.warn('Tool part failed to render; showing safe fallback.', error);
+        }
+    }
+
+    render() {
+        if (!this.state.hasError) {
+            return this.props.children;
+        }
+
+        const message = this.state.error?.message;
+        return (
+            <div className="flex items-center gap-1.5 pr-2 pl-px py-1.5 rounded-xl min-w-0">
+                <div className="h-3.5 w-3.5 flex-shrink-0" style={TOOL_ERROR_ICON_STYLE}>
+                    {getToolIcon(this.props.toolName)}
+                </div>
+                <span className={cn(TOOL_ROW_TITLE_CLASS, 'flex-shrink-0')} style={TOOL_ERROR_TITLE_STYLE}>
+                    {this.props.displayName}
+                </span>
+                {message ? (
+                    <span className={cn(TOOL_ROW_DESCRIPTION_CLASS, 'min-w-0 truncate')} style={{ color: 'var(--tools-description)' }} title={message}>
+                        {this.props.errorLabel}: {message}
+                    </span>
+                ) : null}
+            </div>
+        );
+    }
+}
+
+const ToolPart: React.FC<ToolPartProps> = (props) => {
+    const { t } = useI18n();
+    const toolName = normalizeToolName(props.part.tool) || 'tool';
+    const displayName = getToolMetadata(toolName).displayName;
+
+    return (
+        <ToolPartErrorBoundary
+            displayName={displayName}
+            errorLabel={t('chat.toolPart.error')}
+            resetKey={props.part}
+            toolName={toolName}
+        >
+            <ToolPartContent {...props} />
+        </ToolPartErrorBoundary>
+    );
+};
+
 export default React.memo(ToolPart, (prev, next) => {
     return areRenderRelevantPartsEqual([prev.part], [next.part])
         && prev.isExpanded === next.isExpanded

packages/ui/src/components/chat/message/parts/toolDiffUtils.test.ts

@@ -0,0 +1,85 @@
+import { describe, expect, test } from 'bun:test';
+
+import { getDiffPatchEntries, getRenderablePatchInfo } from './toolDiffUtils';
+
+const identity = (path: string) => path;
+
+describe('toolDiffUtils', () => {
+    test('treats raw apply_patch envelopes as text, not visual diffs', () => {
+        const entries = getDiffPatchEntries(undefined, [
+            '*** Begin Patch',
+            '*** Update File: src/app.ts',
+            '@@ -1 +1 @@',
+            '-old',
+            '+new',
+            '*** End Patch',
+        ].join('\n'), identity);
+
+        expect(entries).toHaveLength(1);
+        expect(entries[0]?.renderMode).toBe('text');
+        expect(entries[0]?.patch).toContain('*** Begin Patch');
+    });
+
+    test('splits multi-file unified patches into one renderable entry per file', () => {
+        const entries = getDiffPatchEntries(undefined, [
+            '--- a/src/a.ts',
+            '+++ b/src/a.ts',
+            '@@ -1 +1 @@',
+            '-old',
+            '+new',
+            '--- a/src/b.ts',
+            '+++ b/src/b.ts',
+            '@@ -1 +1 @@',
+            '-left',
+            '+right',
+        ].join('\n'), identity);
+
+        expect(entries.map((entry) => entry.renderMode)).toEqual(['diff', 'diff']);
+        expect(entries.map((entry) => entry.title)).toEqual(['src/a.ts', 'src/b.ts']);
+    });
+
+    test('uses metadata.files patches before top-level fallback diffs', () => {
+        const entries = getDiffPatchEntries({
+            files: [{
+                relativePath: 'src/file.ts',
+                patch: [
+                    '--- a/src/file.ts',
+                    '+++ b/src/file.ts',
+                    '@@ -1 +1 @@',
+                    '-old',
+                    '+new',
+                ].join('\n'),
+            }],
+        }, 'not a diff', identity);
+
+        expect(entries).toHaveLength(1);
+        expect(entries[0]?.renderMode).toBe('diff');
+        expect(entries[0]?.title).toBe('src/file.ts');
+    });
+
+    test('synthesizes headers for valid headerless hunks', () => {
+        const entries = getDiffPatchEntries(undefined, [
+            '@@ -1 +1 @@',
+            '-old',
+            '+new',
+        ].join('\n'), identity);
+
+        expect(entries).toHaveLength(1);
+        expect(entries[0]?.renderMode).toBe('diff');
+        expect(getRenderablePatchInfo(entries[0]?.patch ?? '')).not.toBeNull();
+    });
+
+    test('keeps malformed unified patches as text fallbacks', () => {
+        const entries = getDiffPatchEntries(undefined, [
+            '--- a/src/file.ts',
+            '+++ b/src/file.ts',
+            '@@',
+            '-old',
+            '+new',
+        ].join('\n'), identity);
+
+        expect(entries).toHaveLength(1);
+        expect(entries[0]?.renderMode).toBe('text');
+        expect(entries[0]?.patch).toContain('@@');
+    });
+});

packages/ui/src/components/chat/message/parts/toolDiffUtils.ts

@@ -0,0 +1,234 @@
+import { parsePatchFiles } from '@pierre/diffs';
+
+export type DiffPatchEntry = {
+    id: string;
+    title: string;
+    patch: string;
+    renderMode: 'diff' | 'text';
+};
+
+const APPLY_PATCH_ENVELOPE_PATTERN = /^\*\*\*\s+(?:Begin Patch|End Patch|Add File:|Update File:|Delete File:|Move to:)/m;
+const HUNK_HEADER_PATTERN = /^@@\s+-\d+(?:,\d+)?\s+\+\d+(?:,\d+)?\s+@@/m;
+const GIT_DIFF_FILE_BREAK_PATTERN = /(?=^diff --git\s+)/gm;
+const GIT_DIFF_FILE_BREAK_TEST = /^diff --git\s+/m;
+const UNIFIED_DIFF_FILE_BREAK_PATTERN = /(?=^---\s+\S)/gm;
+const UNIFIED_DIFF_FILE_BREAK_TEST = /^---\s+\S/m;
+
+const isRecord = (value: unknown): value is Record<string, unknown> => {
+    return typeof value === 'object' && value !== null;
+};
+
+export const normalizePatchText = (patch: string): string => {
+    return patch.replace(/\r\n/g, '\n').replace(/\r/g, '\n').trim();
+};
+
+export const getPatchText = (value: unknown): string | undefined => {
+    if (typeof value === 'string') {
+        return /\S/.test(value) ? value : undefined;
+    }
+
+    if (isRecord(value)) {
+        const patch = value.patch;
+        if (typeof patch === 'string') {
+            return /\S/.test(patch) ? patch : undefined;
+        }
+    }
+
+    return undefined;
+};
+
+const normalizeParsedPath = (path: string | undefined): string => {
+    const trimmed = (path ?? '').trim().replace(/\t.*$/, '');
+    if (!trimmed || trimmed === '/dev/null') {
+        return '';
+    }
+    return trimmed.replace(/^[ab]\//, '');
+};
+
+const makeSyntheticPath = (title: string): string => {
+    const normalized = title.trim().replace(/\s+/g, '-');
+    return normalized.length > 0 ? normalized : 'file';
+};
+
+const hasOnlyUnifiedDiffBodyLines = (patch: string): boolean => {
+    let inHunk = false;
+    for (const line of patch.split('\n')) {
+        if (line.startsWith('@@')) {
+            if (!HUNK_HEADER_PATTERN.test(line)) {
+                return false;
+            }
+            inHunk = true;
+            continue;
+        }
+
+        if (!inHunk || line.length === 0) {
+            continue;
+        }
+
+        const first = line[0];
+        if (first !== ' ' && first !== '+' && first !== '-' && first !== '\\') {
+            return false;
+        }
+    }
+
+    return true;
+};
+
+export const getRenderablePatchInfo = (patch: string): { patch: string; title?: string } | null => {
+    const normalized = normalizePatchText(patch);
+    if (
+        !normalized
+        || APPLY_PATCH_ENVELOPE_PATTERN.test(normalized)
+        || !HUNK_HEADER_PATTERN.test(normalized)
+        || !hasOnlyUnifiedDiffBodyLines(normalized)
+    ) {
+        return null;
+    }
+
+    try {
+        const parsedPatches = parsePatchFiles(normalized, undefined, true);
+        if (parsedPatches.length !== 1) {
+            return null;
+        }
+
+        const files = parsedPatches[0]?.files ?? [];
+        const file = files[0];
+        if (files.length !== 1 || !file || file.hunks.length === 0) {
+            return null;
+        }
+
+        return {
+            patch: normalized,
+            title: normalizeParsedPath(file.name),
+        };
+    } catch {
+        return null;
+    }
+};
+
+const getPatchChunks = (patch: string): string[] => {
+    const isGitDiff = GIT_DIFF_FILE_BREAK_TEST.test(patch);
+    const hasUnifiedDiff = UNIFIED_DIFF_FILE_BREAK_TEST.test(patch);
+    if (!isGitDiff && !hasUnifiedDiff) {
+        return [];
+    }
+
+    return patch
+        .split(isGitDiff ? GIT_DIFF_FILE_BREAK_PATTERN : UNIFIED_DIFF_FILE_BREAK_PATTERN)
+        .map((chunk) => chunk.trim())
+        .filter((chunk) => chunk.length > 0);
+};
+
+const getPatchEntriesFromText = (
+    patch: string,
+    fallbackTitle: string,
+    idPrefix: string,
+    resolveTitle: (path: string) => string,
+): DiffPatchEntry[] => {
+    const normalized = normalizePatchText(patch);
+    if (!normalized) {
+        return [];
+    }
+
+    const direct = getRenderablePatchInfo(normalized);
+    if (direct) {
+        const title = direct.title ? resolveTitle(direct.title) : resolveTitle(fallbackTitle);
+        return [{ id: `${idPrefix}-0`, title, patch: direct.patch, renderMode: 'diff' }];
+    }
+
+    const chunkEntries: DiffPatchEntry[] = [];
+    for (const chunk of getPatchChunks(normalized)) {
+        const info = getRenderablePatchInfo(chunk);
+        const title = info?.title ? resolveTitle(info.title) : resolveTitle(fallbackTitle);
+        if (!info) {
+            if (HUNK_HEADER_PATTERN.test(chunk) || GIT_DIFF_FILE_BREAK_TEST.test(chunk) || UNIFIED_DIFF_FILE_BREAK_TEST.test(chunk)) {
+                chunkEntries.push({
+                    id: `${idPrefix}-${chunkEntries.length}`,
+                    title,
+                    patch: chunk,
+                    renderMode: 'text',
+                });
+            }
+            continue;
+        }
+        chunkEntries.push({
+            id: `${idPrefix}-${chunkEntries.length}`,
+            title,
+            patch: info.patch,
+            renderMode: 'diff',
+        });
+    }
+
+    if (chunkEntries.length > 0) {
+        return chunkEntries;
+    }
+
+    if (!APPLY_PATCH_ENVELOPE_PATTERN.test(normalized) && HUNK_HEADER_PATTERN.test(normalized)) {
+        const syntheticPath = makeSyntheticPath(fallbackTitle);
+        const synthetic = getRenderablePatchInfo(`--- ${syntheticPath}\n+++ ${syntheticPath}\n${normalized}`);
+        if (synthetic) {
+            return [{
+                id: `${idPrefix}-0`,
+                title: resolveTitle(fallbackTitle),
+                patch: synthetic.patch,
+                renderMode: 'diff',
+            }];
+        }
+    }
+
+    return [{
+        id: `${idPrefix}-0`,
+        title: resolveTitle(fallbackTitle),
+        patch: normalized,
+        renderMode: 'text',
+    }];
+};
+
+const getFilePatch = (file: unknown): { patch: string; title: string } | null => {
+    if (!isRecord(file)) {
+        return null;
+    }
+
+    const patch = getPatchText(file.patch) ?? getPatchText(file.diff);
+    if (!patch) {
+        return null;
+    }
+
+    const rawPath = typeof file.relativePath === 'string'
+        ? file.relativePath
+        : typeof file.filePath === 'string'
+            ? file.filePath
+            : '';
+
+    return {
+        patch,
+        title: rawPath,
+    };
+};
+
+export const getDiffPatchEntries = (
+    metadata: Record<string, unknown> | undefined,
+    fallbackDiff: string | undefined,
+    resolveTitle: (path: string) => string,
+): DiffPatchEntry[] => {
+    const files = Array.isArray(metadata?.files) ? metadata.files : [];
+    const fileEntries = files.flatMap((file, index) => {
+        const filePatch = getFilePatch(file);
+        if (!filePatch) {
+            return [];
+        }
+        return getPatchEntriesFromText(
+            filePatch.patch,
+            filePatch.title || `File ${index + 1}`,
+            `file-${index}`,
+            resolveTitle,
+        );
+    });
+
+    if (fileEntries.length > 0) {
+        return fileEntries;
+    }
+
+    const diff = typeof fallbackDiff === 'string' ? fallbackDiff : '';
+    return getPatchEntriesFromText(diff, 'Diff', 'fallback', resolveTitle);
+};