fix: preserve deletion-only AI ratio and remove preview badge

docs/knowledge/investigations.md

@@ -67,6 +67,26 @@ PR #72 で `--fallback-env` を導入し、PR #74 で stale trailer retry と bo
 
 ## Resolved Investigations
 
+### PR #76 deletion-only AI Ratio が 0% になる
+
+- 対象 PR: `#76`
+- 対象 commit: `0bc0e77 fix(dashboard): remove preview badge`
+- 観測結果: Prompt selection と file attribution は正しく、`packages/dashboard/src/pages/index.astro` は `by_ai: true` でした。一方、commit は `Preview` badge の 1 行削除のみだったため `attribution.lines` は `{ "ai_added": 0, "total_added": 0, "deleted": 1 }` になり、PR Report では `AI Ratio: 0%` と表示されました。
+- 原因: `calcAiRatio()` には `totalAddedLines === 0` のとき file-level ratio に fallback する unit test がありました。しかし `buildEntry()` の `resolveMethod()` が先に `method: "none"` を選び、`calcAiRatio()` を呼ぶ前に `ai_ratio: 0` を固定していました。helper 単体の test は存在していたが、実際の entry assembly path を固定していなかったことが漏れの本質です。
+- 修正: `lineCounts` があっても `totalAddedLines === 0` の場合は、eligible file が残っていれば `method: "file"` に fallback します。削除のみ、rename のみ、mode change のように added-line denominator がない commit でも、AI が触った file evidence は AI Ratio に反映します。すべての file が generated artifact / `.agentnoteignore` で AI Ratio 対象外なら、従来通り `method: "none"` です。
+- Regression coverage: `packages/cli/src/core/entry.test.ts` で、`buildEntry()` が `0 added / N deleted / AI file` を `method: "file"` として保存することを確認します。同じ test file で、eligible file が 0 件の場合だけ `method: "none"` に落ちることも確認します。これは `calcAiRatio()` helper だけでなく、git note に保存される final entry contract を固定するための regression です。
+
+#### Test strengthening policy from PR #76
+
+今回の漏れは「低レベル helper の test はあるが、上位 caller がその helper を迂回する」形でした。今後 attribution / prompt selection / report rendering を触るときは、以下を regression 方針として扱います。
+
+- Helper test だけで完了扱いにしません。`calcAiRatio()`、prompt scoring、fallback predicate のような helper を変更した場合は、少なくとも 1 つ上の public contract (`buildEntry()`、`recordCommitEntry()`、`renderMarkdown()`、CLI output) でも同じ境界を固定します。
+- Ratio / attribution の test matrix には、`added > 0` だけでなく `added = 0, deleted > 0`、`added = 0, deleted = 0`、AI file あり、AI file なし、eligible file なし、generated / `.agentnoteignore` 除外を含めます。特に denominator が 0 になる path は、`0%` と `—` と file-level fallback のどれが正しいかを明示します。
+- PR Report / Dashboard / CLI 表示は、stored note の `method` と `lines` の組み合わせを fixture で確認します。`method: "line"` だけでなく、`method: "file"` + `lines` あり、`method: "file"` + `lines` なし、`method: "none"` を分けて見る必要があります。
+- Generated bundle を持つ package の shared core を触った場合は、source test と bundle sync を同じ PR で確認します。`packages/pr-report` は `packages/cli/src/core/entry.ts` を bundle に含むため、CLI 側の attribution bug は Action output にも影響します。
+- Regression test 名には、実ユーザーの症状を入れます。例: `falls back to method=file when line counts have no added lines` のように、内部条件だけでなく「何が守られるか」が分かる名前にします。
+- 「100 ケース」などの数を増やすだけでは十分ではありません。今回のような漏れは scenario count ではなく axis の欠落で起きるため、matrix の各 axis が user-visible contract に接続しているかを review checklist に含めます。
+
 ### CLI dist tracking policy
 
 - 決定: `packages/pr-report/dist/index.js` は tracked artifact として維持します。`action.yml` が GitHub Action runtime でこの bundle を直接実行するため、repository に存在しないと published Action が動きません。

packages/cli/dist/cli.js

@@ -2447,10 +2447,11 @@ function calcAiRatio(files, lineCounts) {
   if (eligible.total === 0) return 0;
   return Math.round(eligible.ai / eligible.total * PERCENT_DENOMINATOR);
 }
-function resolveMethod(lineCounts) {
+function resolveMethod(files, lineCounts) {
   if (!lineCounts) return "file";
-  if (lineCounts.totalAddedLines === 0) return "none";
-  return "line";
+  if (lineCounts.totalAddedLines > 0) return "line";
+  const eligible = countAiRatioEligibleFiles(files);
+  return eligible.total > 0 ? "file" : "none";
 }
 function buildEntry(opts) {
   const generatedFiles = new Set(opts.generatedFiles ?? []);
@@ -2461,7 +2462,7 @@ function buildEntry(opts) {
     ...generatedFiles.has(path) ? { generated: true } : {},
     ...aiRatioExcludedFiles.has(path) ? { ai_ratio_excluded: true } : {}
   }));
-  const method = resolveMethod(opts.lineCounts);
+  const method = resolveMethod(files, opts.lineCounts);
   const aiRatio = method === "none" ? 0 : calcAiRatio(files, opts.lineCounts);
   const attribution = { ai_ratio: aiRatio, method };
   if (opts.lineCounts) {

packages/cli/src/core/entry.test.ts

@@ -517,7 +517,7 @@ describe("buildEntry", () => {
     assert.equal(entry.attribution.lines, undefined);
   });
 
-  it("sets method=none and ai_ratio=0 when totalAddedLines is 0", () => {
+  it("falls back to method=file when line counts have no added lines", () => {
     const lineCounts: LineCounts = { aiAddedLines: 0, totalAddedLines: 0, deletedLines: 5 };
     const entry = buildEntry({
       sessionId,
@@ -526,6 +526,25 @@ describe("buildEntry", () => {
       aiFiles: ["a.ts"],
       lineCounts,
     });
+    assert.equal(entry.attribution.method, "file");
+    assert.equal(entry.attribution.ai_ratio, 100);
+    assert.deepEqual(entry.attribution.lines, {
+      ai_added: 0,
+      total_added: 0,
+      deleted: 5,
+    });
+  });
+
+  it("sets method=none when no added-line or file-level denominator exists", () => {
+    const lineCounts: LineCounts = { aiAddedLines: 0, totalAddedLines: 0, deletedLines: 5 };
+    const entry = buildEntry({
+      sessionId,
+      interactions: [],
+      commitFiles: ["packages/cli/dist/cli.js"],
+      aiFiles: ["packages/cli/dist/cli.js"],
+      aiRatioExcludedFiles: ["packages/cli/dist/cli.js"],
+      lineCounts,
+    });
     assert.equal(entry.attribution.method, "none");
     assert.equal(entry.attribution.ai_ratio, 0);
   });

packages/cli/src/core/entry.ts

@@ -536,11 +536,15 @@ export function calcAiRatio(files: FileEntry[], lineCounts?: LineCounts): number
   return Math.round((eligible.ai / eligible.total) * PERCENT_DENOMINATOR);
 }
 
-/** Determine attribution method from available data. */
-function resolveMethod(lineCounts?: LineCounts): "line" | "file" | "none" {
+/** Determine the strongest safe attribution method for the current commit evidence. */
+function resolveMethod(files: FileEntry[], lineCounts?: LineCounts): "line" | "file" | "none" {
   if (!lineCounts) return "file";
-  if (lineCounts.totalAddedLines === 0) return "none";
-  return "line";
+  if (lineCounts.totalAddedLines > 0) return "line";
+
+  // A deletion-only or rename-only commit has no added-line denominator.
+  // Keep AI involvement visible by falling back to file-level attribution.
+  const eligible = countAiRatioEligibleFiles(files);
+  return eligible.total > 0 ? "file" : "none";
 }
 
 /** Build the final git-note entry from collected session, attribution, and prompt data. */
@@ -566,7 +570,7 @@ export function buildEntry(opts: {
     ...(aiRatioExcludedFiles.has(path) ? { ai_ratio_excluded: true } : {}),
   }));
 
-  const method = resolveMethod(opts.lineCounts);
+  const method = resolveMethod(files, opts.lineCounts);
   const aiRatio = method === "none" ? 0 : calcAiRatio(files, opts.lineCounts);
 
   const attribution: Attribution = { ai_ratio: aiRatio, method };

packages/dashboard/src/pages/index.astro

@@ -1599,7 +1599,6 @@ const dashboardIndex = buildDashboardIndex();
       <aside class="sidebar" id="sidebar">
         <div class="sidebar-header">
           <a href={homePath} class="logo">Agent Note</a>
-          <span class="badge accent">Preview</span>
         </div>
         <div class="tab-row" id="tab-row">
           <button data-tab="prs" class="active">PRs</button>

packages/pr-report/dist/index.js

@@ -36471,6 +36471,10 @@ const SESSION_FILE = "session";
 const SESSION_AGENT_FILE = "agent";
 /** Gemini pending commit state file used between BeforeTool and AfterTool. */
 const PENDING_COMMIT_FILE = "pending_commit.json";
+/** One-shot marker allowing post-commit to recover a stale-heartbeat session. */
+const POST_COMMIT_FALLBACK_FILE = "post_commit_fallback";
+/** Marker value indicating that post-commit may try strict HEAD recovery. */
+const POST_COMMIT_FALLBACK_HEAD = "head";
 // ─── Display limits ───
 /** Maximum commits scanned by commands that need bounded history traversal. */
 const MAX_COMMITS = 500;
@@ -36508,6 +36512,8 @@ const PRE_BLOBS_FILE = "pre_blobs.jsonl";
 const COMMITTED_PAIRS_FILE = "committed_pairs.jsonl";
 /** Session files that prove a commit can produce a non-empty git note. */
 const RECORDABLE_SESSION_FILES = [PROMPTS_FILE, CHANGES_FILE, PRE_BLOBS_FILE];
+/** Session files that let plain git hooks safely attach a session trailer. */
+const TRAILER_SESSION_FILES = [CHANGES_FILE, PRE_BLOBS_FILE];
 // ─── Git ───
 /** SHA-1 hash of a git blob with empty content (canonical git empty blob). */
 const EMPTY_BLOB = "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391";
@@ -36898,13 +36904,16 @@ function calcAiRatio(files, lineCounts) {
         return 0;
     return Math.round((eligible.ai / eligible.total) * PERCENT_DENOMINATOR);
 }
-/** Determine attribution method from available data. */
-function resolveMethod(lineCounts) {
+/** Determine the strongest safe attribution method for the current commit evidence. */
+function resolveMethod(files, lineCounts) {
     if (!lineCounts)
         return "file";
-    if (lineCounts.totalAddedLines === 0)
-        return "none";
-    return "line";
+    if (lineCounts.totalAddedLines > 0)
+        return "line";
+    // A deletion-only or rename-only commit has no added-line denominator.
+    // Keep AI involvement visible by falling back to file-level attribution.
+    const eligible = countAiRatioEligibleFiles(files);
+    return eligible.total > 0 ? "file" : "none";
 }
 /** Build the final git-note entry from collected session, attribution, and prompt data. */
 function buildEntry(opts) {
@@ -36916,7 +36925,7 @@ function buildEntry(opts) {
         ...(generatedFiles.has(path) ? { generated: true } : {}),
         ...(aiRatioExcludedFiles.has(path) ? { ai_ratio_excluded: true } : {}),
     }));
-    const method = resolveMethod(opts.lineCounts);
+    const method = resolveMethod(files, opts.lineCounts);
     const aiRatio = method === "none" ? 0 : calcAiRatio(files, opts.lineCounts);
     const attribution = { ai_ratio: aiRatio, method };
     if (opts.lineCounts) {
@@ -37003,12 +37012,13 @@ async function git(args, options) {
 async function git_gitSafe(args, options) {
     try {
         const stdout = await git(args, options);
-        return { stdout, exitCode: 0 };
+        return { stdout, stderr: "", exitCode: 0 };
     }
     catch (err) {
         const e = err;
         return {
             stdout: typeof e.stdout === "string" ? e.stdout.trim() : "",
+            stderr: typeof e.stderr === "string" ? e.stderr.trim() : "",
             exitCode: typeof e.code === "number" ? e.code : 1,
         };
     }
@@ -37211,7 +37221,10 @@ function injectGitCommitTrailer(command, trailer) {
 /** Write an Agent Note entry as a git note on a commit. */
 async function writeNote(commitSha, data) {
     const body = JSON.stringify(data, null, 2);
-    await gitSafe(["notes", `--ref=${NOTES_REF}`, "add", "-f", "-m", body, commitSha]);
+    const result = await gitSafe(["notes", `--ref=${NOTES_REF}`, "add", "-f", "-m", body, commitSha]);
+    if (result.exitCode !== 0) {
+        throw new Error(result.stderr || "failed to write Agent Note git note");
+    }
 }
 /** Read an Agent Note entry from a git note, returning null when none exists. */
 async function readNote(commitSha) {