feat(review): View diff links in changed-files summary (#2157)

src/queue/processors.ts

@@ -9836,6 +9836,7 @@ async function maybePublishPrPublicSurface(
                 additions: file.additions,
                 deletions: file.deletions,
               })),
+              changedFilesSummaryContext: { repoFullName, pullNumber: pr.number },
             }
           : {}),
         // review.effort_score (#1955): deterministic, no-AI complexity/time estimate — only computed when the

src/review/changed-files-diff-link.ts

@@ -0,0 +1,24 @@
+/** GitHub PR Files-tab diff anchors for changed-files summary links (#2157). */
+
+import { createHash } from "node:crypto";
+
+const REPO_FULL_NAME = /^[A-Za-z0-9_.-]+\/[A-Za-z0-9_.-]+$/;
+
+/** PURE: SHA-256 hex of the bare repo-relative path — GitHub's `#diff-…` anchor on the Files tab. */
+export function githubPrFileDiffAnchor(path: string): string | null {
+  const trimmed = path.trim();
+  if (!trimmed || trimmed.includes("\0")) return null;
+  return createHash("sha256").update(trimmed, "utf8").digest("hex");
+}
+
+/** PURE: public-safe PR Files-tab URL for one changed file, or null when inputs cannot be anchored. */
+export function githubPrFileDiffUrl(
+  repoFullName: string,
+  pullNumber: number,
+  path: string,
+): string | null {
+  if (!REPO_FULL_NAME.test(repoFullName) || !Number.isInteger(pullNumber) || pullNumber <= 0) return null;
+  const anchor = githubPrFileDiffAnchor(path);
+  if (anchor === null) return null;
+  return `https://github.com/${repoFullName}/pull/${pullNumber}/files#diff-${anchor}`;
+}

src/review/unified-comment-bridge.ts

@@ -29,6 +29,7 @@ import type { CaptureRoute } from "./visual/capture";
 import { PR_PANEL_COMMENT_MARKER } from "../github/comments";
 import { GITTENSORY_GATE_CHECK_NAME } from "./check-names";
 import { classifyChangedFile, type ReviewFileClass } from "./changed-files-classify";
+import { githubPrFileDiffUrl } from "./changed-files-diff-link";
 import { classifyFindingCategory, FINDING_CATEGORIES, type FindingCategory } from "./finding-category-classify";
 import {
   buildUnifiedReviewInput,
@@ -315,6 +316,8 @@ export type UnifiedCommentBridgeArgs = {
    *  passes this only when the manifest opts in — see `resolveReviewPromptOverrides`'s `changedFilesSummary`).
    *  (#1957) */
   changedFilesSummary?: ChangedFileSummaryInput[] | undefined;
+  /** Repo + PR number for per-file "View diff" links in the changed-files table (#2157). */
+  changedFilesSummaryContext?: ChangedFilesSummaryContext | undefined;
   /** Deterministic per-PR review-effort estimate (review.effort_score port, `src/review/review-effort.ts`). When
    *  present, a compact `review effort: N/5 (~M min)` chip is appended to the status-chip row (passed straight
    *  through to `buildUnifiedReviewInput`'s `reviewEffort`). No AI. Default OFF (the processor passes this only
@@ -454,6 +457,17 @@ export function buildScrollPreviewCollapsible(routes: CaptureRoute[]): UnifiedCo
  *  doesn't drag GitHub's full file-record shape into its pure-rendering surface. */
 export type ChangedFileSummaryInput = { path: string; additions: number; deletions: number };
 
+/** Repo + PR coordinates for per-file "View diff" links on the changed-files table (#2157). */
+export type ChangedFilesSummaryContext = { repoFullName: string; pullNumber: number };
+
+function markdownChangedFilePath(value: string): string {
+  return `\`${value
+    .replace(/\\/g, "\\\\")
+    .replace(/`/g, "\\`")
+    .replace(/\|/g, "\\|")
+    .replace(/[<>]/g, (char) => (char === "<" ? "&lt;" : "&gt;"))}\``;
+}
+
 /** Display order for the "Changed files" table — SOURCE FIRST, mirroring the same source-first priority this
  *  codebase already applies to the AI reviewer's own diff ordering (`diffFilePriority`,
  *  `src/review/review-diff.ts`): the code a maintainer most needs to read leads, generated/mechanical output
@@ -469,14 +483,30 @@ const CHANGED_FILE_CATEGORY_LABEL: Record<ReviewFileClass, string> = {
 };
 
 /**
- * Build the "Changed files" collapsible: one row per file category (source/test/docs/config/generated, via
- * the deterministic `classifyChangedFile`), with a file count and +/- totals — collapsing an arbitrarily large
- * same-category group into a single row so a big PR doesn't turn into a wall of per-file lines. No AI, no
- * network — pure grouping over data the caller already has. Returns null when there are no files (nothing to
- * summarize), so the caller can unconditionally chain this alongside the other optional collapsibles.
+ * Build the "Changed files" collapsible. Without `context`, groups by category (source/test/docs/config/generated)
+ * with file counts and +/- totals — byte-identical to #2145. With `context`, renders one row per file (sorted
+ * source-first) and a public-safe GitHub Files-tab "View diff" link per row (#2157).
  */
-export function buildChangedFilesSummaryCollapsible(files: ChangedFileSummaryInput[]): UnifiedCollapsible | null {
+export function buildChangedFilesSummaryCollapsible(
+  files: ChangedFileSummaryInput[],
+  context?: ChangedFilesSummaryContext | undefined,
+): UnifiedCollapsible | null {
   if (files.length === 0) return null;
+  if (context) {
+    const sorted = [...files].sort((left, right) => {
+      const leftCategory = CHANGED_FILE_CATEGORY_ORDER.indexOf(classifyChangedFile(left.path));
+      const rightCategory = CHANGED_FILE_CATEGORY_ORDER.indexOf(classifyChangedFile(right.path));
+      if (leftCategory !== rightCategory) return leftCategory - rightCategory;
+      return left.path.localeCompare(right.path);
+    });
+    const rows = sorted.map((file) => {
+      const diffUrl = githubPrFileDiffUrl(context.repoFullName, context.pullNumber, file.path);
+      const diffCell = diffUrl ? `[View diff](${diffUrl})` : "—";
+      return `| ${markdownChangedFilePath(file.path)} | +${file.additions} | -${file.deletions} | ${diffCell} |`;
+    });
+    const body = ["| File | Added | Removed | |", "| --- | --- | --- | --- |", ...rows].join("\n");
+    return { title: "Changed files", body };
+  }
   const totals = new Map<ReviewFileClass, { count: number; additions: number; deletions: number }>();
   for (const file of files) {
     const category = classifyChangedFile(file.path);
@@ -665,7 +695,7 @@ export function buildUnifiedCommentBody(args: UnifiedCommentBridgeArgs): string
   // before pixels). Flag-OFF (the processor passes undefined) ⇒ extraCollapsibles is unchanged. (#1957)
   const changedFilesCollapsible =
     args.changedFilesSummary && args.changedFilesSummary.length > 0
-      ? buildChangedFilesSummaryCollapsible(args.changedFilesSummary)
+      ? buildChangedFilesSummaryCollapsible(args.changedFilesSummary, args.changedFilesSummaryContext)
       : null;
   const withChangedFiles =
     changedFilesCollapsible !== null ? [...(withManifestValidation ?? []), changedFilesCollapsible] : withManifestValidation;

test/unit/changed-files-diff-link.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, it } from "vitest";
+import { githubPrFileDiffAnchor, githubPrFileDiffUrl } from "../../src/review/changed-files-diff-link";
+
+describe("githubPrFileDiffAnchor (#2157)", () => {
+  it("returns the SHA-256 hex of the bare repo-relative path", () => {
+    expect(githubPrFileDiffAnchor("src/app.ts")).toBe(
+      "841254fe75488c1bd4cd7f68f00b4be0e48dcfbc4a16b45847b68295e0e3b27b",
+    );
+  });
+
+  it("returns null for empty or whitespace-only paths", () => {
+    expect(githubPrFileDiffAnchor("")).toBeNull();
+    expect(githubPrFileDiffAnchor("   ")).toBeNull();
+    expect(githubPrFileDiffAnchor("\0bad")).toBeNull();
+  });
+});
+
+describe("githubPrFileDiffUrl (#2157)", () => {
+  it("builds a public-safe Files-tab URL with the diff anchor", () => {
+    expect(githubPrFileDiffUrl("acme/widgets", 42, "src/app.ts")).toBe(
+      "https://github.com/acme/widgets/pull/42/files#diff-841254fe75488c1bd4cd7f68f00b4be0e48dcfbc4a16b45847b68295e0e3b27b",
+    );
+  });
+
+  it("returns null for invalid repo, PR number, or path", () => {
+    expect(githubPrFileDiffUrl("not-a-repo", 1, "src/a.ts")).toBeNull();
+    expect(githubPrFileDiffUrl("acme/widgets", 0, "src/a.ts")).toBeNull();
+    expect(githubPrFileDiffUrl("acme/widgets", 1.5, "src/a.ts")).toBeNull();
+    expect(githubPrFileDiffUrl("acme/widgets", 1, "")).toBeNull();
+  });
+});

test/unit/changed-files-summary-collapsible.test.ts

@@ -28,17 +28,86 @@ const files: ChangedFileSummaryInput[] = [
   { path: "package-lock.json", additions: 100, deletions: 50 },
 ];
 
+describe("buildChangedFilesSummaryCollapsible per-file diff links (#2157)", () => {
+  const context = { repoFullName: "acme/widgets", pullNumber: 42 };
+
+  it("renders one row per file with a View diff link when context is provided", () => {
+    const c = buildChangedFilesSummaryCollapsible(files, context);
+    expect(c).not.toBeNull();
+    expect(c?.body).toContain("| File | Added | Removed | |");
+    expect(c?.body).toContain(
+      "| `src/app.ts` | +40 | -10 | [View diff](https://github.com/acme/widgets/pull/42/files#diff-",
+    );
+    expect(c?.body).not.toContain("| Source | 2 | +45 | -10 |");
+  });
+
+  it("sorts same-category files by path when context is provided", () => {
+    const c = buildChangedFilesSummaryCollapsible(
+      [
+        { path: "src/z.ts", additions: 1, deletions: 0 },
+        { path: "src/a.ts", additions: 2, deletions: 0 },
+      ],
+      context,
+    );
+    const body = c?.body ?? "";
+    expect(body.indexOf("src/a.ts")).toBeLessThan(body.indexOf("src/z.ts"));
+  });
+
+  it("escapes adversarial path characters in per-file rows", () => {
+    const c = buildChangedFilesSummaryCollapsible(
+      [{ path: "src/weird\\path|`file<1>.ts", additions: 1, deletions: 0 }],
+      context,
+    );
+    expect(c?.body).toContain("&lt;1&gt;");
+    expect(c?.body).toContain("\\`");
+    expect(c?.body).toContain("\\|");
+    expect(c?.body).toContain("\\\\");
+  });
+
+  it("omits the View diff link when the path or repo context cannot be anchored", () => {
+    const unanchored = buildChangedFilesSummaryCollapsible([{ path: "   ", additions: 1, deletions: 0 }], context);
+    expect(unanchored?.body).toContain("| `   ` | +1 | -0 | — |");
+
+    const badRepo = buildChangedFilesSummaryCollapsible(
+      [{ path: "src/a.ts", additions: 1, deletions: 0 }],
+      { repoFullName: "not-a-repo", pullNumber: 1 },
+    );
+    expect(badRepo?.body).toContain("| `src/a.ts` | +1 | -0 | — |");
+  });
+
+  it("orders per-file rows source-first across categories when context is provided", () => {
+    const c = buildChangedFilesSummaryCollapsible(
+      [
+        { path: "docs/readme.md", additions: 1, deletions: 0 },
+        { path: "src/app.ts", additions: 2, deletions: 0 },
+      ],
+      context,
+    );
+    const body = c?.body ?? "";
+    expect(body.indexOf("src/app.ts")).toBeLessThan(body.indexOf("docs/readme.md"));
+  });
+
+  it("escapes a greater-than character in per-file paths", () => {
+    const c = buildChangedFilesSummaryCollapsible([{ path: "src/file>name.ts", additions: 1, deletions: 0 }], context);
+    expect(c?.body).toContain("&gt;");
+  });
+
+  it("keeps collapsed category rows without links when context is omitted", () => {
+    const c = buildChangedFilesSummaryCollapsible(files);
+    expect(c?.body).toContain("| Source | 2 | +45 | -10 |");
+    expect(c?.body).not.toContain("[View diff]");
+  });
+});
+
 describe("buildChangedFilesSummaryCollapsible (#2145)", () => {
   it("groups changed files by category with file counts and +/- totals", () => {
     const c = buildChangedFilesSummaryCollapsible(files);
     expect(c).not.toBeNull();
     expect(c?.title).toBe("Changed files");
     expect(c?.body).toContain("| Category | Files | Added | Removed |");
-    // Two source files collapse into ONE row with summed totals (45 = 40 + 5, 10 = 10 + 0).
     expect(c?.body).toContain("| Source | 2 | +45 | -10 |");
     expect(c?.body).toContain("| Test | 1 | +20 | -2 |");
     expect(c?.body).toContain("| Docs | 1 | +3 | -1 |");
-    // A lockfile classifies as generated.
     expect(c?.body).toContain("| Generated | 1 | +100 | -50 |");
   });
 
@@ -78,7 +147,18 @@ describe("buildUnifiedCommentBody changedFilesSummary wiring (#1957 / #2145)", (
     footerMarkdown: footer,
   };
 
-  it("appends the Changed files section when changedFilesSummary is present + non-empty", () => {
+  it("appends per-file View diff links when changedFilesSummaryContext is present (#2157)", () => {
+    const body = buildUnifiedCommentBody({
+      ...base,
+      changedFilesSummary: files,
+      changedFilesSummaryContext: { repoFullName: "acme/widgets", pullNumber: 42 },
+    });
+    expect(body).toContain("Changed files");
+    expect(body).toContain("[View diff](https://github.com/acme/widgets/pull/42/files#diff-");
+    expect(body).not.toContain("| Source | 2 | +45 | -10 |");
+  });
+
+  it("appends the grouped Changed files section when changedFilesSummary is present without context (#2145)", () => {
     const body = buildUnifiedCommentBody({ ...base, changedFilesSummary: files });
     expect(body).toContain("Changed files");
     expect(body).toContain("| Source | 2 | +45 | -10 |");

test/unit/queue.test.ts

@@ -16974,11 +16974,10 @@ describe("queue processors", () => {
 
       expect(calls.comments).toBe(2);
       expect(postedBody).toContain("<!-- gittensory-pr-panel:v1 -->");
-      // The new deterministic, no-AI collapsible — one row per category, collapsing the source file and the
-      // doc file into their own rows with the mocked +/- totals.
+      // The deterministic changed-files collapsible — per-file rows with GitHub Files-tab links (#2157).
       expect(postedBody).toContain("Changed files");
-      expect(postedBody).toContain("| Source | 1 | +5 | -1 |");
-      expect(postedBody).toContain("| Docs | 1 | +2 | -0 |");
+      expect(postedBody).toContain("| `src/cache.ts` | +5 | -1 | [View diff](https://github.com/JSONbored/gittensory/pull/3/files#diff-");
+      expect(postedBody).toContain("| `README.md` | +2 | -0 | [View diff](https://github.com/JSONbored/gittensory/pull/3/files#diff-");
     } finally {
       liveCiSpy.mockRestore();
     }