Inline comments (#10)

A finding about one line now lands on that line of the diff: the agent writes anchors as JSON, and the review posts them with the body in one call. Bad entries fail the run, and an anchor Gitea refuses falls back to posting the body alone.

Verified with deno fmt, lint and check.

Reviewed-on: #10
Co-authored-by: bot <temeddix@gmail.com>
Co-committed-by: bot <temeddix@gmail.com>

prompt.md

@@ -39,13 +39,24 @@ never ask `@bot` to make them. For UI changes, check that the result is aligned,
 clean, and pixel-perfect, and that included screenshots prove the intended
 result was achieved.
 
-The review must read at a glance: everything outside `<details>` blocks totals
-under 512 bytes. Only core information stays visible: the verdict, the summary
-line, and the section headings. Anything verbose goes into a `<details>` block
-whose `<summary>` is a few words, such as the `file:line` and title of an issue
-with the what, why, and how inside; the same for each strength, each
-recommendation, the reasoning, and any compliance notes. Details blocks are
-top-level, never inside a list item, because Gitea breaks them there.
+Every finding that belongs to one line of the diff goes on that line instead of
+into the body. Write those to `${ANCHORS_PATH}` as a JSON array, each entry
+`{"path": "<path from the repository root>", "line": <number>, "side": "new" |
+"old", "body": "<the finding>"}`.
+`side` is `new` for a line in the head file and `old` for one only in the base
+file; `line` is that file's own line number, and it must be a line the diff
+touches, or Gitea refuses the anchor. Write the file only when there is
+something to anchor, and keep each body to the what, the why, and the how, with
+no `file:line` prefix; the line carries that.
+
+The review body must read at a glance: everything outside `<details>` blocks
+totals under 512 bytes. Only core information stays visible: the verdict, the
+summary line, and the section headings. Anything verbose goes into a `<details>`
+block whose `<summary>` is a few words, such as the title of an issue with the
+what, why, and how inside; the same for each strength, each recommendation, the
+reasoning, and any compliance notes. A finding you anchored belongs there only
+as its title, since its detail is on the line. Details blocks are top-level,
+never inside a list item, because Gitea breaks them there.
 
 For an `issue_comment` or `pull_request_review_comment` event, treat the `body`
 in the triggering comment payload below as the user's exact instruction.

run.ts

@@ -64,12 +64,50 @@ async function postComment(body: string): Promise<void> {
 // picks up narration while a file's first line is written on purpose. That line
 // is the verdict, matched whole; anything unexpected only comments, never
 // approves. The mark in front is added here, so it is never part of the match.
-const REVIEW_PATH = `${await Deno.makeTempDir()}/review.md`;
+const REVIEW_DIR = await Deno.makeTempDir();
+const REVIEW_PATH = `${REVIEW_DIR}/review.md`;
 const VERDICTS: Record<string, [event: string, mark: string]> = {
   Approved: ["APPROVED", "✅"],
   "Changes requested": ["REQUEST_CHANGES", "🛑"],
 };
 
+// A finding about one line is posted on that line of the diff rather than as
+// `file:line` prose in the body. Those anchors come as JSON, so the file and
+// line are structured instead of parsed back out of English; a malformed entry
+// fails the run, because a silently dropped finding is worse than a red run.
+const ANCHORS_PATH = `${REVIEW_DIR}/anchors.json`;
+type Anchor = { path: string; line: number; side: "new" | "old"; body: string };
+
+function parseAnchors(text: string): Anchor[] {
+  const entries: unknown = JSON.parse(text);
+  if (!Array.isArray(entries)) throw new Error(`${ANCHORS_PATH}: not an array`);
+  return entries.map((entry: unknown, index) => {
+    const at = `${ANCHORS_PATH}[${index}]`;
+    if (typeof entry !== "object" || entry === null) {
+      throw new Error(`${at}: not an object`);
+    }
+    const { path, line, side = "new", body } = entry as Record<string, unknown>;
+    if (typeof path !== "string" || path === "") {
+      throw new Error(`${at}.path: expected a repository path`);
+    }
+    if (typeof line !== "number" || !Number.isInteger(line) || line < 1) {
+      throw new Error(`${at}.line: expected a line number`);
+    }
+    if (side !== "new" && side !== "old") {
+      throw new Error(`${at}.side: expected "new" or "old"`);
+    }
+    if (typeof body !== "string" || body.trim() === "") {
+      throw new Error(`${at}.body: expected the finding`);
+    }
+    return { path, line, side, body };
+  });
+}
+
+async function readAnchors(): Promise<Anchor[]> {
+  const written = await Deno.readTextFile(ANCHORS_PATH).catch(() => null);
+  return written === null ? [] : parseAnchors(written);
+}
+
 async function postResult(body: string): Promise<void> {
   const review = await Deno.readTextFile(REVIEW_PATH).catch(() => null);
   if (review === null) {
@@ -80,9 +118,25 @@ async function postResult(body: string): Promise<void> {
   }
   const [verdict, ...rest] = review.split("\n");
   const [event, mark] = VERDICTS[verdict.trim()] ?? ["COMMENT", "💬"];
-  await gitea(REVIEWER_TOKEN, `repos/${REPO}/pulls/${INDEX}/reviews`, {
+  const post = (anchors: Anchor[]) =>
+    gitea(REVIEWER_TOKEN, `repos/${REPO}/pulls/${INDEX}/reviews`, {
       body: stripAnsi([`${mark} ${verdict.trim()}`, ...rest].join("\n")),
       event,
+      comments: anchors.map(({ path, line, side, body }) => ({
+        path,
+        body: stripAnsi(body),
+        new_position: side === "new" ? line : 0,
+        old_position: side === "old" ? line : 0,
+      })),
+    });
+  const anchors = await readAnchors();
+  // Gitea rejects the whole review when an anchor names a line outside the
+  // diff, and a verdict that never lands blocks the pull request, so the body
+  // goes up alone rather than not at all.
+  await post(anchors).catch(async (error: Error) => {
+    if (anchors.length === 0) throw error;
+    console.error(`inline comments rejected: ${error.message}`);
+    await post([]);
   });
 }
 
@@ -128,6 +182,7 @@ async function renderPrompt(): Promise<string> {
     GITEA_REPOSITORY: REPO,
     ISSUE_INDEX: INDEX,
     REVIEW_PATH,
+    ANCHORS_PATH,
   };
   const template = await Deno.readTextFile(
     new URL("prompt.md", import.meta.url),