feat(review): add "All files" diff type (#629)

* feat(review): add "All files" diff type for reviewing entire codebases

Adds an "all" diff type that diffs the empty tree against HEAD, showing
every tracked file as an addition. Solves the case where a repo has only
committed changes and no working tree diffs — previously there was no way
to launch a review at all.

For provenance purposes, this commit was AI assisted.

* fix(review): add "All files" to Settings panel diff type options

The Settings panel (gear icon) had its own DEFAULT_DIFF_TYPE_OPTIONS list
that was missing the new "all" diff type, so users couldn't select or see
it as the default from the settings UI.

For provenance purposes, this commit was AI assisted.

* fix(review): rename "All files" to "All files (HEAD)" for clarity

Makes it clear this mode shows committed state at HEAD, not the working
tree. Updated tooltip to distinguish from "Committed changes" (which
diffs against a base branch).

For provenance purposes, this commit was AI assisted.

Author: backnotprop

packages/review-editor/App.tsx

@@ -951,7 +951,7 @@ const ReviewApp: React.FC = () => {
       const lastColon = rest.lastIndexOf(':');
       if (lastColon !== -1) {
         const sub = rest.slice(lastColon + 1);
-        if (['uncommitted', 'staged', 'unstaged', 'last-commit', 'branch', 'merge-base'].includes(sub)) {
+        if (['uncommitted', 'staged', 'unstaged', 'last-commit', 'branch', 'merge-base', 'all'].includes(sub)) {
           return { activeWorktreePath: rest.slice(0, lastColon), activeDiffBase: sub };
         }
       }
@@ -1977,6 +1977,7 @@ const ReviewApp: React.FC = () => {
                           {activeDiffBase === 'last-commit' && `No changes in the last commit${activeWorktreePath ? ' in this worktree' : ''}.`}
                           {activeDiffBase === 'branch' && `No changes vs ${selectedBase || gitContext?.defaultBranch || 'main'}${activeWorktreePath ? ' in this worktree' : ''}.`}
                           {activeDiffBase === 'merge-base' && `No changes vs ${selectedBase || gitContext?.defaultBranch || 'main'}${activeWorktreePath ? ' in this worktree' : ''}.`}
+                          {activeDiffBase === 'all' && `No tracked files${activeWorktreePath ? ' in this worktree' : ' in this repository'}.`}
                         </p>
                       </>
                     )}

packages/review-editor/components/DiffTypePicker.tsx

@@ -22,6 +22,7 @@ const OPTION_HINTS: Record<string, string> = {
   'last-commit': "Just your most recent commit.",
   branch: "Straight compare against the base branch (picked below). Can show commits that aren't yours if the base has new commits.",
   'merge-base': "Only what you've added on top of the base branch (picked below). Same as GitHub's PR view.",
+  all: "Every tracked file at HEAD, shown as additions. Unlike Committed, which shows what changed vs a base branch, this shows the entire codebase.",
 };
 
 export const DiffTypePicker: React.FC<DiffTypePickerProps> = ({

packages/review-editor/utils/exportFeedback.ts

@@ -38,6 +38,7 @@ function describeDiff(ctx: FeedbackDiffContext): string {
     case "last-commit":  label = "Last commit"; break;
     case "branch":       label = base ? `Branch diff vs \`${base}\`` : "Branch diff"; break;
     case "merge-base":   label = base ? `Committed changes vs \`${base}\`` : "Committed changes"; break;
+    case "all":          label = "All files"; break;
     default:             label = mode; // p4-* or anything else — show raw
   }
   return worktreePath ? `${label} _(worktree: ${worktreePath})_` : label;

packages/server/codex-review.ts

@@ -223,6 +223,9 @@ export function buildCodexReviewUserMessage(
       return `Review the PR-style diff against base '${base}'. First find the common ancestor with \`git merge-base ${base} HEAD\`, then run \`git diff <merge-base>..HEAD\` using that commit to inspect only the changes introduced on this branch (matches GitHub's PR view). Provide prioritized, actionable findings.`;
     }
 
+    case "all":
+      return "Review every file in the repository (all files shown as additions, diffed against an empty tree). Provide prioritized, actionable findings.";
+
     default:
       // p4 or unknown — fall back to generic with inlined diff
       return [

packages/server/tour/tour-review.ts

@@ -338,6 +338,8 @@ function buildTourUserMessage(
       const base = options?.defaultBranch || "main";
       return `Walk the reviewer through the PR-style diff against base '${base}' as a guided tour. First find the common ancestor with \`git merge-base ${base} HEAD\`, then run \`git diff <merge-base>..HEAD\` using that commit to inspect only the changes introduced on this branch (matches GitHub's PR view).`;
     }
+    case "all":
+      return "Walk the reviewer through every file in the repository as a guided tour. All files are shown as additions (diffed against an empty tree).";
     default:
       return [
         "Walk the reviewer through the following code changes as a guided tour.",

packages/server/vcs.ts

@@ -72,7 +72,7 @@ export interface VcsProvider {
 
 // --- Git provider ---
 
-const GIT_DIFF_TYPES = new Set(["uncommitted", "staged", "unstaged", "last-commit", "branch", "merge-base"]);
+const GIT_DIFF_TYPES = new Set(["uncommitted", "staged", "unstaged", "last-commit", "branch", "merge-base", "all"]);
 
 const gitProvider: VcsProvider = {
   id: "git",

packages/shared/config.ts

@@ -10,7 +10,7 @@ import { join } from "path";
 import { readFileSync, writeFileSync, mkdirSync, existsSync } from "fs";
 import { execSync } from "child_process";
 
-export type DefaultDiffType = 'uncommitted' | 'unstaged' | 'staged' | 'merge-base';
+export type DefaultDiffType = 'uncommitted' | 'unstaged' | 'staged' | 'merge-base' | 'all';
 
 export interface DiffOptions {
   diffStyle?: 'split' | 'unified';
@@ -198,7 +198,7 @@ export function getServerConfig(gitUser: string | null): {
 export function resolveDefaultDiffType(cfg?: PlannotatorConfig): DefaultDiffType {
   const v = cfg?.diffOptions?.defaultDiffType as string | undefined;
   if (v === 'branch') return 'merge-base';
-  return v === 'uncommitted' || v === 'unstaged' || v === 'staged' || v === 'merge-base' ? v : 'unstaged';
+  return v === 'uncommitted' || v === 'unstaged' || v === 'staged' || v === 'merge-base' || v === 'all' ? v : 'unstaged';
 }
 
 /**

packages/shared/review-core.ts

@@ -14,6 +14,7 @@ export type DiffType =
   | "last-commit"
   | "branch"
   | "merge-base"
+  | "all"
   | `worktree:${string}`
   | "p4-default"
   | `p4-changelist:${string}`;
@@ -275,6 +276,8 @@ export async function getGitContext(
     diffOptions.push({ id: "merge-base", label: "Committed changes" });
   }
 
+  diffOptions.push({ id: "all", label: "All files (HEAD)" });
+
   const [worktrees, currentTreePathResult] = await Promise.all([
     getWorktrees(runtime, cwd),
     runtime.runGit(["rev-parse", "--show-toplevel"], { cwd }),
@@ -368,6 +371,7 @@ const WORKTREE_SUB_TYPES = new Set([
   "last-commit",
   "branch",
   "merge-base",
+  "all",
 ]);
 
 export function parseWorktreeDiffType(
@@ -539,6 +543,29 @@ export async function runGitDiff(
         break;
       }
 
+      case "all": {
+        // Diff from the empty tree to HEAD — shows every tracked file as an addition.
+        const emptyTreeResult = await runtime.runGit(["hash-object", "-t", "tree", "/dev/null"], { cwd });
+        const emptyTree = emptyTreeResult.exitCode === 0
+          ? emptyTreeResult.stdout.trim()
+          : "4b825dc642cb6eb9a060e54bf8d69288fbee4904";
+        const allDiffArgs = [
+          "diff",
+          "--no-ext-diff",
+          "--src-prefix=a/",
+          "--dst-prefix=b/",
+          "--end-of-options",
+          `${emptyTree}..HEAD`,
+        ];
+        const allDiff = assertGitSuccess(
+          await runtime.runGit(allDiffArgs, { cwd }),
+          allDiffArgs,
+        );
+        patch = allDiff.stdout;
+        label = "All files";
+        break;
+      }
+
       default:
         return { patch: "", label: "Unknown diff type" };
     }
@@ -637,6 +664,11 @@ export async function getFileContentsForDiff(
         newContent: await gitShow("HEAD", filePath),
       };
     }
+    case "all":
+      return {
+        oldContent: null,
+        newContent: await gitShow("HEAD", filePath),
+      };
     default:
       return { oldContent: null, newContent: null };
   }

packages/ui/components/DiffTypeSetupDialog.tsx

@@ -26,6 +26,11 @@ const OPTIONS: { value: DefaultDiffType; label: string; description: string }[]
     label: 'Committed',
     description: "Everything you've committed on this branch",
   },
+  {
+    value: 'all',
+    label: 'All Files (HEAD)',
+    description: "Every tracked file at HEAD, shown as additions",
+  },
 ];
 
 interface DiffTypeSetupDialogProps {

packages/ui/components/Settings.tsx

@@ -126,6 +126,7 @@ const DEFAULT_DIFF_TYPE_OPTIONS = [
   { value: 'unstaged' as const, label: 'Unstaged', description: "Only changes you haven't staged yet" },
   { value: 'staged' as const, label: 'Staged', description: "Only changes you've staged for commit" },
   { value: 'merge-base' as const, label: 'Committed', description: "Everything you've committed on this branch" },
+  { value: 'all' as const, label: 'All Files (HEAD)', description: "Every tracked file at HEAD, shown as additions" },
 ];
 
 function SegmentedControl<T extends string>({ options, value, onChange }: {