From bcacbf062d509f12f33a6dd694fcea3e2ff43139 Mon Sep 17 00:00:00 2001
From: Ben Stull <ben.stull@wiggleverse.org>
Date: Fri, 12 Jun 2026 00:13:54 -0700
Subject: [PATCH] F10 SLICE-2: fix renderReview author-coloring for duplicate
 blocks; tidy renderReviewOp + escape proposal id (#29)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 src/trackChangesModel.ts       | 21 +++++++++++----------
 test/trackChangesModel.test.ts | 12 ++++++++++++
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/trackChangesModel.ts b/src/trackChangesModel.ts
index 6c28726..0f92c97 100644
--- a/src/trackChangesModel.ts
+++ b/src/trackChangesModel.ts
@@ -437,7 +437,7 @@ function proposalBlockHtml(p: ProposalView, render: (src: string) => string): st
     `<button class="cw-accept" data-action="accept">✓</button>` +
     `<button class="cw-reject" data-action="reject">✗</button>` +
     `</span>`;
-  return `<div class="cw-proposal${unanchored}" data-proposal-id="${p.id}">${actions}${before}${after}</div>`;
+  return `<div class="cw-proposal${unanchored}" data-proposal-id="${md.utils.escapeHtml(p.id)}">${actions}${before}${after}</div>`;
 }
 
 function renderReviewOp(
@@ -445,9 +445,9 @@ function renderReviewOp(
   render: (src: string) => string,
   colored: (raw: string) => string,
 ): string {
-  if (op.kind === "removed") return renderOp(op, render);
-  if (op.kind === "changed" && op.atomic) return renderOp(op, render);
-  if (op.kind === "changed") return renderOp(op, render); // word-merged <ins>/<del>
+  // removed blocks and any changed block (atomic fences diffed whole; non-atomic prose
+  // word-merged) render via renderOp — no author sentinels (deletions neutral, spec §6.7).
+  if (op.kind === "removed" || op.kind === "changed") return renderOp(op, render);
   return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}">${colored(op.block.raw)}</div>`;
 }
 
@@ -468,12 +468,13 @@ export function renderReview(
   const render = opts.render ?? defaultRender;
   const ranges = splitBlocksWithRanges(currentText);
   const ops = diffBlocks(baselineText, currentText);
-  const colored = (raw: string): string => {
-    const blk = ranges.find((r) => r.raw === raw);
-    if (!blk) return render(raw);
-    return colorByAuthor(raw, blk.start, authorSpans, render);
-  };
-  const bodyParts = ops.map((op) => renderReviewOp(op, render, colored));
+  let ci = 0; // pointer into ranges; advances for every op with a current-side block
+  const bodyParts = ops.map((op) => {
+    const blk = op.kind === "removed" ? undefined : ranges[ci++];
+    const colored = (raw: string): string =>
+      blk ? colorByAuthor(raw, blk.start, authorSpans, render) : render(raw);
+    return renderReviewOp(op, render, colored);
+  });
   const anchored = proposals.filter((p) => p.anchorStart !== null);
   const unanchored = proposals.filter((p) => p.anchorStart === null);
   const proposalParts = [...anchored, ...unanchored].map((p) => proposalBlockHtml(p, render));
diff --git a/test/trackChangesModel.test.ts b/test/trackChangesModel.test.ts
index 0a27195..55c6ef5 100644
--- a/test/trackChangesModel.test.ts
+++ b/test/trackChangesModel.test.ts
@@ -295,6 +295,18 @@ describe("renderReview", () => {
     expect(html).toContain("mermaid");
     expect(html).not.toContain("cw-by-");
   });
+  test("renderReview: author-colors the correct block when two paragraphs are identical", () => {
+    // Two identical paragraphs; baseline has only the first, so the SECOND is an
+    // added block authored by human. Its span must color THAT block, not the first.
+    const baseline = "Hello world";
+    const current = "Hello world\n\nHello world";
+    // second "Hello world" starts at offset 13; "world" at 19..24
+    const spans = [{ start: 19, end: 24, author: "human" as const }];
+    const html = renderReview(baseline, current, spans, []);
+    // exactly one cw-by-human span (the added second block's "world"), not zero, not on the first.
+    const count = (html.match(/cw-by-human/g) ?? []).length;
+    expect(count).toBe(1);
+  });
 });
 
 import { renderTrackChanges as rtc2 } from "../src/trackChangesModel";