F12: inline editable proposed-change diff in the Markdown editor + Accept/Reject control parity (#64) (#66)

test/decorationPlan.test.ts

@@ -0,0 +1,27 @@
+import { describe, test, expect } from "vitest";
+import { decorationPlan } from "../src/trackChangesModel";
+
+describe("decorationPlan (INV-49)", () => {
+  test("derives insertion ranges + deletion hints from original→replacement", () => {
+    // anchorStart 10; original 'the brown fox' → 'the red fox'
+    const plan = decorationPlan(10, "the brown fox", "the red fox");
+    // one changed run: 'brown ' → 'red ' (word-level); insertion 'red ' tinted,
+    // deletion hint 'brown ' shown at the run start.
+    expect(plan.insertions.length).toBeGreaterThan(0);
+    expect(plan.deletions.length).toBeGreaterThan(0);
+    // insertion offsets are in buffer coords (>= anchorStart) and lie within the applied text
+    for (const ins of plan.insertions) {
+      expect(ins.start).toBeGreaterThanOrEqual(10);
+      expect(ins.end).toBeLessThanOrEqual(10 + "the red fox".length);
+    }
+    // a deletion hint carries the struck original text at a buffer offset
+    expect(plan.deletions[0].text).toContain("brown");
+  });
+
+  test("pure insertion (no deletion) yields an insertion range and no deletion hint", () => {
+    // 'hello' → 'hello world': ' world' is a pure word-level insertion (no removed tokens)
+    const plan = decorationPlan(0, "hello", "hello world");
+    expect(plan.insertions.length).toBe(1);
+    expect(plan.deletions.length).toBe(0);
+  });
+});

test/e2e/runTest.ts

@@ -13,11 +13,20 @@ async function main(): Promise<void> {
   const workspace = fs.mkdtempSync(path.join(os.tmpdir(), "cowriting-e2e-"));
   fs.cpSync(fixture, workspace, { recursive: true });
 
+  // VS Code derives its IPC socket path from --user-data-dir. The default
+  // (`<projectRoot>/.vscode-test/user-data`) plus `/<version>-main.sock` can blow
+  // past macOS's ~103-char UNIX-socket limit (`listen EINVAL`) when the project
+  // lives at a long path (e.g. a git worktree). Pin the user-data dir to a SHORT
+  // root under /tmp so the socket path stays well under the limit. (os.tmpdir() on
+  // macOS is itself a long /var/folders/… path, so we use /tmp directly.)
+  const userDataRoot = process.platform === "win32" ? os.tmpdir() : "/tmp";
+  const userDataDir = fs.mkdtempSync(path.join(userDataRoot, "cwud-"));
+
   try {
     await runTests({
       extensionDevelopmentPath,
       extensionTestsPath,
-      launchArgs: [workspace, "--disable-extensions"],
+      launchArgs: [workspace, "--disable-extensions", "--user-data-dir", userDataDir],
       extensionTestsEnv: { E2E_WORKSPACE: workspace },
     });
 
@@ -26,10 +35,11 @@ async function main(): Promise<void> {
     await runTests({
       extensionDevelopmentPath,
       extensionTestsPath: path.resolve(__dirname, "./suite-no-workspace/index"),
-      launchArgs: ["--disable-extensions"],
+      launchArgs: ["--disable-extensions", "--user-data-dir", userDataDir],
     });
   } finally {
     fs.rmSync(workspace, { recursive: true, force: true });
+    fs.rmSync(userDataDir, { recursive: true, force: true });
   }
 }
 

test/e2e/suite/f10Review.test.ts

@@ -109,8 +109,9 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     const pIdx = html.indexOf(`data-proposal-id="${id}"`);
     const t2Idx = html.indexOf("second claude target");
     assert.ok(t2Idx >= 0 && pIdx < t2Idx, "the proposal renders in place, before the following block (#31)");
-    // INV-10: proposing never touches the document.
-    assert.ok(doc.getText().includes(T1), "document unchanged by propose");
+    // F12 (INV-48): EditorProposalController auto-applies the proposal into the buffer;
+    // the replacement text is now in the document, proposal is still pending.
+    assert.ok(doc.getText().includes("A FIRST claude REPLACEMENT sentence."), "F12 optimistic-apply: replacement in buffer");
   });
 
   test("accept → the proposal lands, clears from the preview, and the baseline advances (PUC-4)", async () => {
@@ -131,17 +132,18 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     assert.ok(!marked, "the just-landed Claude text renders unmarked (baseline advanced)");
   });
 
-  test("reject → the proposal vanishes and the document is untouched (PUC-5)", async () => {
+  test("reject → the proposal vanishes and the document is reverted (PUC-5)", async () => {
     const { doc, key } = await reopen(DOC_REL);
     const api = await getApi();
     const before = doc.getText();
     const id2 = await propose(doc, key, T2, "A SECOND would-be replacement.", "turn-f10-2");
     await settle();
     assert.ok(api.proposalController.listProposals(doc).some((v) => v.id === id2), "second proposal pending");
-    assert.strictEqual(api.proposalController.rejectById(DOC_REL, id2), true, "reject");
+    // F12: use rejectByIdInPlace to revert the optimistically-applied buffer edit.
+    assert.ok(await api.proposalController.rejectByIdInPlace(DOC_REL, id2), "rejectByIdInPlace reverts + removes");
     await settle();
     assert.ok(!api.proposalController.listProposals(doc).some((v) => v.id === id2), "rejected proposal gone");
-    assert.strictEqual(doc.getText(), before, "document untouched by reject");
+    assert.strictEqual(doc.getText(), before, "document reverted to pre-propose state");
     const html = api.trackChangesPreviewController.renderHtmlFor(key);
     assert.ok(!html.includes(`data-proposal-id="${id2}"`), "no rejected block in the preview");
   });

test/e2e/suite/f11Toolbar.test.ts

@@ -99,8 +99,9 @@ suite("F11 preview toolbar (host E2E — message → seam wiring, no LLM)", () =
       "The quick RED fox jumps over the lazy CAT.",
       "the block proposal carries the whole rewritten paragraph",
     );
-    // INV-10: proposing never mutates the document.
-    assert.ok(doc.getText().includes("brown fox") && doc.getText().includes("lazy dog"), "document unchanged by propose");
+    // F12 (INV-48): EditorProposalController optimistically applies the proposed text,
+    // so after settle the buffer has the replacement. The proposal is still pending.
+    assert.ok(doc.getText().includes("RED fox") && doc.getText().includes("lazy CAT"), "F12 optimistic-apply: proposed text in buffer");
     void key;
   });
 
@@ -129,7 +130,9 @@ suite("F11 preview toolbar (host E2E — message → seam wiring, no LLM)", () =
     assert.ok(view, "the proposal is live");
     assert.strictEqual(view!.replacement, "The REWRITTEN paragraph from Claude.", "carries the turn replacement");
     assert.strictEqual(view!.replaced, target, "replaces exactly the selected range");
-    assert.ok(doc.getText().includes(target), "document unchanged by propose (INV-10)");
+    // F12 (INV-48): the EditorProposalController optimistically applies, so the buffer
+    // now has the replacement. `view.replaced` still records the original target text.
+    assert.ok(doc.getText().includes("The REWRITTEN paragraph from Claude."), "F12 optimistic-apply: proposed text in buffer");
     void key;
   });
 

test/e2e/suite/f12InlineDiff.test.ts

@@ -0,0 +1,251 @@
+import * as assert from "assert";
+import * as fs from "fs";
+import * as path from "path";
+import * as vscode from "vscode";
+import type { CowritingApi } from "../../../src/extension";
+import { addProposal, setProposalApplied } from "../../../src/proposalModel";
+import { buildFingerprint } from "../../../src/anchorer";
+
+const WS = process.env.E2E_WORKSPACE!;
+const settle = () => new Promise((r) => setTimeout(r, 400));
+
+async function getApi(): Promise<CowritingApi> {
+  const ext = vscode.extensions.getExtension("benstull.vscode-cowriting-plugin")!;
+  const api = (await ext.activate()) as CowritingApi;
+  assert.ok(api?.trackChangesPreviewController && api?.proposalController, "exports controllers");
+  return api;
+}
+
+async function freshDoc(rel: string, body: string): Promise<{ doc: vscode.TextDocument; key: string }> {
+  const abs = path.join(WS, rel);
+  fs.mkdirSync(path.dirname(abs), { recursive: true });
+  fs.writeFileSync(abs, body, "utf8");
+  const uri = vscode.Uri.file(abs);
+  const doc = await vscode.workspace.openTextDocument(uri);
+  await vscode.window.showTextDocument(doc);
+  await settle();
+  return { doc, key: uri.toString() };
+}
+
+suite("F12 inline diff — seam landBaseline (#64, INV-48)", () => {
+  test("applyAgentEdit with landBaseline:false applies text but does NOT advance the baseline", async () => {
+    const { doc, key } = await freshDoc("docs/f12-land.md", "# T\n\nalpha here.\n");
+    const api = await getApi();
+    await vscode.commands.executeCommand("cowriting.showTrackChangesPreview");
+    await settle();
+    const before = api.diffViewController.getBaseline(key)?.text ?? doc.getText();
+    const start = doc.getText().indexOf("alpha");
+    const ok = await api.attributionController.applyAgentEdit(
+      doc,
+      new vscode.Range(doc.positionAt(start), doc.positionAt(start + "alpha".length)),
+      "ALPHA",
+      { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } },
+      { landBaseline: false },
+    );
+    await settle();
+    assert.ok(ok, "edit applied");
+    assert.ok(doc.getText().includes("ALPHA"), "text in buffer");
+    assert.strictEqual(api.diffViewController.getBaseline(key)?.text ?? doc.getText(), before, "baseline unchanged");
+  });
+});
+
+suite("F12 inline diff — finalize / revert in place (#64, INV-51)", () => {
+  // Optimistic apply lands the text + re-anchors; the buffer becomes the accepted result.
+  test("optimisticApply puts the proposed text in the buffer and re-anchors", async () => {
+    const { doc } = await freshDoc("docs/f12-opt.md", "# T\n\nReplace alpha please.\n");
+    const api = await getApi();
+    const p = api.proposalController;
+    const fp = { text: "Replace alpha please.", before: "", after: "", lineHint: 2 };
+    const id = await p.propose(doc, fp, "Replace ALPHA please.",
+      { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } }, { granularity: "block" });
+    await api.proposalController.optimisticApply(doc, id!);
+    await settle();
+    assert.ok(doc.getText().includes("Replace ALPHA please."), "applied to buffer");
+    // re-anchored: the proposal still resolves against the mutated buffer
+    assert.strictEqual(p.listProposals(doc)[0].anchorStart !== null, true, "re-anchored, resolves");
+    assert.strictEqual(p.listProposals(doc)[0].original, "Replace alpha please.", "original stored");
+  });
+
+  test("finalizeInPlace clears the proposal and keeps the applied text (no double-apply)", async () => {
+    const { doc } = await freshDoc("docs/f12-fin.md", "# T\n\nKeep alpha now.\n");
+    const api = await getApi();
+    const p = api.proposalController;
+    const docPath = p.keyFor(doc);
+    const fp = { text: "Keep alpha now.", before: "", after: "", lineHint: 2 };
+    const id = await p.propose(doc, fp, "Keep ALPHA now.",
+      { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } }, { granularity: "block" });
+    await p.optimisticApply(doc, id!);
+    await settle();
+    const ok = await p.finalizeInPlace(docPath, id!);
+    await settle();
+    assert.ok(ok, "finalized");
+    assert.strictEqual(doc.getText(), "# T\n\nKeep ALPHA now.\n", "applied text retained, no double-apply");
+    assert.strictEqual(p.listProposals(doc).length, 0, "proposal cleared");
+  });
+
+  test("revertInPlace restores the original and clears the proposal", async () => {
+    const { doc } = await freshDoc("docs/f12-rev.md", "# T\n\nUndo alpha here.\n");
+    const api = await getApi();
+    const p = api.proposalController;
+    const docPath = p.keyFor(doc);
+    const fp = { text: "Undo alpha here.", before: "", after: "", lineHint: 2 };
+    const id = await p.propose(doc, fp, "Undo ALPHA here.",
+      { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } }, { granularity: "block" });
+    await p.optimisticApply(doc, id!);
+    await settle();
+    const ok = await p.revertInPlace(docPath, id!);
+    await settle();
+    assert.ok(ok, "reverted");
+    assert.strictEqual(doc.getText(), "# T\n\nUndo alpha here.\n", "original restored");
+    assert.strictEqual(p.listProposals(doc).length, 0, "proposal cleared");
+  });
+
+  test("rejectAll reverts every pending proposal", async () => {
+    const { doc } = await freshDoc("docs/f12-rejall.md", "# T\n\nOne aaa.\n\nTwo bbb.\n");
+    const api = await getApi();
+    const ctl = api.trackChangesPreviewController;
+    const p = api.proposalController;
+    ctl.setEditTurnForTest(async () => ({ replacement: "# T\n\nOne AAA.\n\nTwo BBB.\n", model: "m", sessionId: "s" }));
+    const ids = await ctl.runEditAndPropose(doc, { kind: "document" }, "up");
+    await settle();
+    for (const id of ids) await p.optimisticApply(doc, id);
+    await settle();
+    assert.ok(doc.getText().includes("AAA") && doc.getText().includes("BBB"), "both applied");
+    const { reverted } = await p.rejectAll(doc);
+    await settle();
+    assert.strictEqual(reverted, ids.length, "all reverted");
+    assert.strictEqual(doc.getText(), "# T\n\nOne aaa.\n\nTwo bbb.\n", "document restored");
+    assert.strictEqual(p.listProposals(doc).length, 0, "all cleared");
+  });
+});
+
+suite("F12 inline diff — INV-50 listProposals.replaced", () => {
+  test("listProposals reports the original as `replaced` after optimistic apply", async () => {
+    const { doc } = await freshDoc("docs/f12-replaced.md", "# R\n\nbrown here.\n");
+    const api = await getApi();
+    const ctl = api.trackChangesPreviewController;
+    ctl.setEditTurnForTest(async () => ({ replacement: "# R\n\nred here.\n", model: "m", sessionId: "s" }));
+    await ctl.runEditAndPropose(doc, { kind: "document" }, "x");
+    await settle(); await settle();
+    assert.strictEqual(api.proposalController.listProposals(doc)[0].replaced, "brown here.");
+  });
+});
+
+suite("F12 inline diff — editor surface (#64, INV-48/52)", () => {
+  test("proposing optimistically applies into the editor and the buffer is the accepted result", async () => {
+    const { doc } = await freshDoc("docs/f12-editor.md", "# E\n\nThe brown fox runs.\n");
+    const api = await getApi();
+    const ctl = api.trackChangesPreviewController;
+    ctl.setEditTurnForTest(async () => ({ replacement: "# E\n\nThe red fox runs.\n", model: "m", sessionId: "s" }));
+    await ctl.runEditAndPropose(doc, { kind: "document" }, "recolor the fox");
+    await settle(); await settle();
+    assert.ok(doc.getText().includes("The red fox runs."), "optimistically applied into the buffer");
+    const v = api.proposalController.listProposals(doc)[0];
+    assert.strictEqual(v.original, "The brown fox runs.", "original captured for the deletion hint/revert");
+  });
+
+  test("editing the inserted text then finalizing keeps the human edit", async () => {
+    const { doc } = await freshDoc("docs/f12-edit-keep.md", "# E\n\nalpha word here.\n");
+    const api = await getApi();
+    const ctl = api.trackChangesPreviewController;
+    ctl.setEditTurnForTest(async () => ({ replacement: "# E\n\nALPHA word here.\n", model: "m", sessionId: "s" }));
+    const ids = await ctl.runEditAndPropose(doc, { kind: "document" }, "up");
+    await settle(); await settle();
+    // human tweaks the inserted text
+    const at = doc.getText().indexOf("ALPHA");
+    const we = new vscode.WorkspaceEdit();
+    we.replace(doc.uri, new vscode.Range(doc.positionAt(at), doc.positionAt(at + 5)), "ALPHA!");
+    await vscode.workspace.applyEdit(we);
+    await settle();
+    // keyFor(doc) gives the repo-relative path that finalizeInPlace uses as its key;
+    // the `key` from freshDoc is the URI string, which would not match for in-workspace docs.
+    const docKey = api.proposalController.keyFor(doc);
+    await api.proposalController.finalizeInPlace(docKey, ids[0]);
+    await settle();
+    assert.ok(doc.getText().includes("ALPHA! word here."), "human edit preserved on accept");
+    assert.strictEqual(api.proposalController.listProposals(doc).length, 0, "cleared");
+  });
+});
+
+suite("F12 inline diff — control parity (#64, INV-53)", () => {
+  test("reject from the webview reverts in place; rejectAll clears every proposal", async () => {
+    const { doc, key } = await freshDoc("docs/f12-parity.md", "# P\n\nuno aaa.\n\ndos bbb.\n");
+    const api = await getApi();
+    const ctl = api.trackChangesPreviewController;
+    await vscode.commands.executeCommand("cowriting.showTrackChangesPreview");
+    await settle();
+    ctl.setEditTurnForTest(async () => ({ replacement: "# P\n\nuno AAA.\n\ndos BBB.\n", model: "m", sessionId: "s" }));
+    const ids = await ctl.runEditAndPropose(doc, { kind: "document" }, "up");
+    await settle(); await settle();
+    assert.ok(doc.getText().includes("AAA") && doc.getText().includes("BBB"));
+    // reject ONE via the webview intent → that block reverts, the other stays applied
+    ctl.receiveMessage(key, { type: "reject", proposalId: ids[0] });
+    await settle(); await settle();
+    assert.ok(doc.getText().includes("uno aaa.") && doc.getText().includes("BBB"), "one reverted, one applied");
+    // rejectAll via the command → all gone, document restored
+    ctl.receiveMessage(key, { type: "rejectAll" });
+    await settle(); await settle();
+    assert.strictEqual(doc.getText(), "# P\n\nuno aaa.\n\ndos bbb.\n", "document restored");
+    assert.strictEqual(api.proposalController.listProposals(doc).length, 0);
+  });
+
+  test("cowriting.rejectAllProposals is registered + markdown-guarded", async () => {
+    const all = await vscode.commands.getCommands(true);
+    assert.ok(all.includes("cowriting.rejectAllProposals"));
+    const pkg = JSON.parse(fs.readFileSync(path.join(__dirname, "../../../../package.json"), "utf8"));
+    const entry = (pkg.contributes.menus.commandPalette as Array<{ command: string; when?: string }>).find(
+      (m) => m.command === "cowriting.rejectAllProposals",
+    );
+    assert.ok(entry && /editorLangId == markdown/.test(entry.when ?? ""), "palette-guarded on markdown");
+  });
+});
+
+// Reload-safety: a proposal that was optimistically applied in a PRIOR session
+// persists with `original` set and its fp re-anchored to the applied text. A fresh
+// controller (empty in-memory `applied` set) must NOT re-capture `original` from the
+// already-applied buffer — doing so would clobber the true revert target and break
+// Reject. (Regression for the final-review CRITICAL; INV-51/54.)
+suite("F12 inline diff — reload-safety (#64, INV-51/54)", () => {
+  test("optimisticApply does not clobber a previously-persisted original", async () => {
+    const TRUE_ORIGINAL = "The original sentence here.";
+    const APPLIED = "The APPLIED sentence here.";
+    const { doc } = await freshDoc("docs/f12-reload.md", `# R\n\n${TRUE_ORIGINAL}\n`);
+    const api = await getApi();
+    const p = api.proposalController;
+    const key = p.keyFor(doc);
+
+    // 1) The buffer holds the APPLIED text (as the saved-while-pending file would).
+    const at = doc.getText().indexOf(TRUE_ORIGINAL);
+    const we = new vscode.WorkspaceEdit();
+    we.replace(doc.uri, new vscode.Range(doc.positionAt(at), doc.positionAt(at + TRUE_ORIGINAL.length)), APPLIED);
+    assert.ok(await vscode.workspace.applyEdit(we), "apply the prior-session applied text");
+    await settle();
+
+    // 2) Record the proposal directly in the sidecar exactly as a prior session left
+    //    it: fp anchored to the APPLIED text + `original` = the TRUE original. We do
+    //    NOT call optimisticApply, so this controller's in-memory `applied` stays empty.
+    const appliedAt = doc.getText().indexOf(APPLIED);
+    const appliedFp = buildFingerprint(doc.getText(), { start: appliedAt, end: appliedAt + APPLIED.length });
+    let id = "";
+    api.sidecarRouter.update(key, (a) => {
+      id = addProposal(a, appliedFp, APPLIED, { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } }, { granularity: "block" }).proposalId;
+      setProposalApplied(a, id, appliedFp, TRUE_ORIGINAL);
+    });
+    p.renderAll(doc);
+    await settle();
+
+    // 3) Re-entry as a reload would trigger (EditorProposalController re-applies on
+    //    onDidChangeProposals because `applied` is empty). The guard must preserve original.
+    await p.optimisticApply(doc, id);
+    await settle();
+    const view = p.listProposals(doc).find((v) => v.id === id);
+    assert.ok(view, "proposal still present");
+    assert.strictEqual(view!.original, TRUE_ORIGINAL, "true original preserved, NOT clobbered with the applied text");
+
+    // 4) Reject restores the TRUE original (not the applied text).
+    assert.ok(await p.revertInPlace(key, id), "revert");
+    await settle();
+    assert.ok(doc.getText().includes(TRUE_ORIGINAL), "reject restored the true original");
+    assert.ok(!doc.getText().includes(APPLIED), "applied text removed on reject");
+  });
+});

test/e2e/suite/f12Reach.test.ts

@@ -98,8 +98,10 @@ suite("F12 SLICE-1 — Ask-Claude reach (#42, INV-38)", () => {
       0,
       "active doc A was NOT edited — editDocument honored the tab URI",
     );
-    // INV-10: proposing never mutates the document.
-    assert.ok(b.doc.getText().includes("tab target paragraph"), "tab doc unchanged by propose");
+    // F12 (INV-48): EditorProposalController optimistically applies proposals into the
+    // buffer, so the proposed text is now in the tab doc B. Confirm one of the proposal
+    // texts is present (the tab doc was edited, not A).
+    assert.ok(b.doc.getText().includes("REWRITTEN"), "F12 optimistic-apply: proposed text in tab doc B");
   });
 
   // No URI arg (palette / keybinding) → fall back to the active editor.

test/e2e/suite/liveProgress.test.ts

@@ -50,7 +50,10 @@ suite("#60 live turn progress (additive + cancel)", () => {
     assert.strictEqual(ids.length, 1, "one changed block → one proposal, regardless of progress events");
     const view = api.proposalController.listProposals(doc).find((v) => v.id === ids[0]);
     assert.ok(view, "the proposal is live");
-    assert.ok(doc.getText().includes("Old paragraph."), "document unchanged by propose (INV-10)");
+    // F12 (INV-48): the EditorProposalController optimistically applies the proposed
+    // text into the buffer, so after settle the active-editor buffer shows the
+    // replacement. The proposal is still pending (not finalized) until Accept.
+    assert.ok(doc.getText().includes("New paragraph."), "F12 optimistic-apply: proposed text in buffer");
   });
 
   test("an aborted turn proposes nothing (INV-47)", async () => {

test/e2e/suite/proposals.test.ts

@@ -63,13 +63,14 @@ suite("F4 propose/accept (host E2E — programmatic ingress, no LLM)", () => {
   const TARGET = "The propose target sentence lives here.";
   const REPLACEMENT = "PROPOSED-BY-CLAUDE replacement sentence.";
 
-  test("propose records + renders a pending proposal and does NOT touch the document (INV-10)", async () => {
+  test("propose records a pending proposal; F12 optimistically applies it (INV-48, reverses INV-10)", async () => {
     const doc = await openDoc();
     const api = await getApi();
-    const before = doc.getText();
     await proposeViaCommand(doc, TARGET, REPLACEMENT, "turn-p1");
     await settle();
-    assert.strictEqual(doc.getText(), before, "document text unchanged (INV-10)");
+    // F12 (INV-48): EditorProposalController auto-applies the proposed text into the
+    // buffer, so after settle the buffer has the replacement text (INV-10 is reversed).
+    assert.ok(doc.getText().includes(REPLACEMENT), "F12 optimistic-apply: replacement in buffer after propose");
     const rendered = api.proposalController.getRendered(DOC_REL);
     assert.strictEqual(rendered.length, 1);
     assert.strictEqual(rendered[0].pending, true);
@@ -77,7 +78,8 @@ suite("F4 propose/accept (host E2E — programmatic ingress, no LLM)", () => {
     assert.strictEqual(rendered[0].canReply, false, "proposals are decide-only — no dead reply input (INV-12)");
     const art = readSidecar();
     assert.strictEqual(art.proposals.length, 1, "proposal persisted at propose time");
-    assert.strictEqual(art.anchors[art.proposals[0].anchorId].fingerprint.text, TARGET);
+    // After optimistic apply, the fingerprint re-anchors to the replacement text.
+    assert.strictEqual(art.anchors[art.proposals[0].anchorId].fingerprint.text, REPLACEMENT);
   });
 
   test("accept applies via the seam: text replaced, Claude-attributed, proposal removed (INV-9/11/13)", async () => {
@@ -97,15 +99,18 @@ suite("F4 propose/accept (host E2E — programmatic ingress, no LLM)", () => {
     assert.strictEqual(readSidecar().proposals.length, 0, "removed from the sidecar");
   });
 
-  test("reject leaves the document untouched and removes the proposal (PUC-3)", async () => {
+  test("reject reverts the optimistically-applied text and removes the proposal (PUC-3, F12-INV-48)", async () => {
     const doc = await openDoc();
     const api = await getApi();
     const before = doc.getText();
     const id = await proposeViaCommand(doc, "A second target for coexistence checks.", "WOULD-BE replacement.", "turn-p2");
     await settle();
-    assert.strictEqual(api.proposalController.rejectById(DOC_REL, id), true);
+    // F12: optimistic apply has put "WOULD-BE replacement." in the buffer.
+    assert.ok(doc.getText().includes("WOULD-BE replacement."), "F12: optimistically applied");
+    // rejectByIdInPlace reverts the buffer to the original (PUC-3, INV-51).
+    assert.ok(await api.proposalController.rejectByIdInPlace(DOC_REL, id), "rejectByIdInPlace removes + reverts");
     await settle();
-    assert.strictEqual(doc.getText(), before, "document untouched");
+    assert.strictEqual(doc.getText(), before, "document restored to pre-propose state");
     assert.strictEqual(api.proposalController.getRendered(DOC_REL).length, 0);
     assert.strictEqual(readSidecar().proposals.length, 0);
   });
@@ -114,25 +119,35 @@ suite("F4 propose/accept (host E2E — programmatic ingress, no LLM)", () => {
     let doc = await openDoc();
     const api = await getApi();
     const anchor = "A stable closing paragraph.";
-    await proposeViaCommand(doc, anchor, "A PROPOSED closing paragraph.", "turn-p3");
+    const appliedText = "A PROPOSED closing paragraph.";
+    await proposeViaCommand(doc, anchor, appliedText, "turn-p3");
     await settle();
+    // F12: optimistic apply has put the proposed text in the buffer (anchor → appliedText).
+    assert.ok(doc.getText().includes(appliedText), "F12: optimistically applied before reload");
     const uri = vscode.Uri.file(path.join(WS, DOC_REL));
+    // doc.getText() now has appliedText; the reload prepends a line.
     doc = await externalWriteAndReload(uri, "PREPENDED LINE\n\n" + doc.getText());
     await settle();
     api.proposalController.renderAll(doc);
     const rendered = api.proposalController.getRendered(DOC_REL);
     assert.strictEqual(rendered.length, 1, "proposal survived reload");
     assert.strictEqual(rendered[0].pending, true, "still decidable");
-    const moved = doc.getText().indexOf(anchor);
-    assert.strictEqual(rendered[0].range.start, moved, "re-anchored after the move");
+    // After F12 re-anchor, the fingerprint tracks the appliedText, not the original anchor.
+    const moved = doc.getText().indexOf(appliedText);
+    assert.ok(moved >= 0, "applied text present in the reloaded document");
+    assert.strictEqual(rendered[0].range.start, moved, "re-anchored to appliedText after the move");
   });
 
   test("editing the target text makes the proposal stale: flagged, accept refused, doc untouched (INV-11)", async () => {
     let doc = await openDoc();
     const api = await getApi();
     const id = api.proposalController.getRendered(DOC_REL)[0].id;
-    const mangled = doc.getText().replace("A stable closing paragraph.", "A reworded closing paragraph.");
-    doc = await externalWriteAndReload(vscode.Uri.file(path.join(WS, DOC_REL)), mangled);
+    // After F12 optimistic apply the fingerprint tracks the APPLIED text ("A PROPOSED
+    // closing paragraph."), not the original.  Mangle that text to make the proposal stale.
+    const preMangled = doc.getText();
+    const mangled = preMangled.replace("A PROPOSED closing paragraph.", "A reworded closing paragraph.");
+    const uri = vscode.Uri.file(path.join(WS, DOC_REL));
+    doc = await externalWriteAndReload(uri, mangled);
     await settle();
     api.proposalController.renderAll(doc);
     assert.strictEqual(api.proposalController.getStaleCount(DOC_REL), 1, "flagged stale");
@@ -143,22 +158,30 @@ suite("F4 propose/accept (host E2E — programmatic ingress, no LLM)", () => {
     assert.strictEqual(readSidecar().proposals.length, 1, "proposal still pending (recoverable)");
     // discard the husk so later tests see a clean sidecar
     assert.strictEqual(api.proposalController.rejectById(DOC_REL, id), true);
+    // Restore the file so subsequent tests can find their fixture targets:
+    // replace the optimistically-applied text back to the original fixture text.
+    const restored = preMangled.replace("A PROPOSED closing paragraph.", "A stable closing paragraph.");
+    doc = await externalWriteAndReload(uri, restored);
+    await settle();
   });
 
   test("multiple pending proposals coexist and are decidable out of order (PUC-5)", async () => {
     const doc = await openDoc();
     const api = await getApi();
-    const id1 = await proposeViaCommand(doc, "A stable opening paragraph.", "An ACCEPTED opening paragraph.", "turn-p4");
-    const id2 = await proposeViaCommand(doc, "PROPOSED-BY-CLAUDE replacement sentence.", "A REPLACED-AGAIN sentence.", "turn-p5");
+    // Clean up any proposals left over from prior tests (F12: proposals persist in state).
+    await api.proposalController.rejectAll(doc);
     await settle();
-    assert.strictEqual(api.proposalController.getRendered(DOC_REL).length, 2);
+    const id1 = await proposeViaCommand(doc, "A stable opening paragraph.", "An ACCEPTED opening paragraph.", "turn-p4");
+    const id2 = await proposeViaCommand(doc, "A stable closing paragraph.", "A REPLACED closing paragraph.", "turn-p5");
+    await settle();
+    assert.strictEqual(api.proposalController.getRendered(DOC_REL).length, 2, "two new proposals");
     // decide the SECOND first, then the first — order independence
     assert.strictEqual(await api.proposalController.acceptById(DOC_REL, id2), true);
     await settle();
     assert.strictEqual(await api.proposalController.acceptById(DOC_REL, id1), true);
     await settle();
     assert.ok(doc.getText().includes("An ACCEPTED opening paragraph."));
-    assert.ok(doc.getText().includes("A REPLACED-AGAIN sentence."));
+    assert.ok(doc.getText().includes("A REPLACED closing paragraph."));
     assert.strictEqual(api.proposalController.getRendered(DOC_REL).length, 0);
   });
 });

test/model.test.ts

@@ -1,4 +1,5 @@
-import { describe, it, expect } from "vitest";
+import assert from "node:assert";
+import { describe, it, test, expect } from "vitest";
 import {
   SCHEMA_VERSION,
   emptyArtifact,
@@ -179,6 +180,19 @@ describe("unknown-field preservation (F5 SLICE-2, INV-15)", () => {
   });
 });
 
+test("serializeArtifact round-trips Proposal.original", () => {
+  const a = emptyArtifact("doc.md");
+  a.anchors["a_1"] = { fingerprint: { text: "new", before: "", after: "", lineHint: 0 } };
+  a.proposals.push({
+    id: "pr_1", anchorId: "a_1", replacement: "new",
+    author: { kind: "agent", id: "claude", agent: { sdk: "@cline/sdk", model: "sonnet", sessionId: "s" } },
+    createdAt: "2026-06-26T00:00:00.000Z", original: "old", granularity: "block",
+  });
+  const json = serializeArtifact(a);
+  assert.match(json, /"original": "old"/);
+  assert.match(json, /"granularity": "block"/);
+});
+
 describe("attributions[] (F3 SLICE-1)", () => {
   it("round-trips an attribution record through serialize → parse", () => {
     const a = emptyArtifact("docs/x.md");

test/proposalModel.test.ts

@@ -9,7 +9,7 @@ import {
   type Proposal,
 } from "../src/model";
 import { CoauthorStore } from "../src/store";
-import { addProposal, proposalBody, removeProposal } from "../src/proposalModel";
+import { addProposal, proposalBody, removeProposal, setProposalApplied } from "../src/proposalModel";
 
 const agent = {
   kind: "agent" as const,
@@ -104,4 +104,19 @@ describe("proposalModel helpers (spec §6.4)", () => {
     expect(body).toContain("- old line two");
     expect(body).toContain("+ new only line");
   });
+
+  it("setProposalApplied stores original and re-anchors the fingerprint to the applied text", () => {
+    const a = emptyArtifact("docs/x.md");
+    const { proposalId, anchorId } = addProposal(
+      a,
+      { text: "old", before: "", after: "", lineHint: 0 },
+      "new",
+      { kind: "agent", id: "claude", agent: { sdk: "x", model: "m", sessionId: "s" } },
+      { granularity: "block" },
+    );
+    setProposalApplied(a, proposalId, { text: "new", before: "", after: "", lineHint: 0 }, "old");
+    const p = a.proposals.find((x) => x.id === proposalId)!;
+    expect(p.original).toBe("old");
+    expect(a.anchors[anchorId].fingerprint.text).toBe("new");
+  });
 });

test/trackChangesModel.test.ts

@@ -231,7 +231,7 @@ describe("renderReview", () => {
     const html = renderReview("hello world", "hello", [], []);
     expect(html).toMatch(/<del>|cw-del/);
   });
-  test("renderReview: a pending proposal renders a blue block with data-proposal-id and ✓/✗ actions", () => {
+  test("renderReview: a pending proposal renders a blue block with data-proposal-id and Accept/Reject actions", () => {
     const proposals: ProposalView[] = [{ id: "p1", anchorStart: 0, anchorEnd: 5, replaced: "hello", replacement: "goodbye" }];
     const html = renderReview("hello", "hello", [], proposals);
     expect(html).toContain('class="cw-proposal"');
@@ -375,6 +375,55 @@ describe("renderReview", () => {
     const b = renderReview(doc, doc, [], proposals);
     expect(a).toBe(b);
   });
+
+  test("renderReview renders an applied proposal ONCE, not also as a landed diff (INV-50)", () => {
+    const baseline = "# T\n\nThe brown fox.\n";
+    const current = "# T\n\nThe red fox.\n"; // proposal already optimistically applied
+    const proposals: ProposalView[] = [{
+      id: "pr_1",
+      anchorStart: current.indexOf("The red fox."),
+      anchorEnd: current.indexOf("The red fox.") + "The red fox.".length,
+      replaced: "The brown fox.",      // original
+      replacement: "The red fox.",
+    }];
+    const html = renderReview(baseline, current, [], proposals);
+    // exactly one proposal block
+    expect((html.match(/cw-proposal/g) ?? []).length).toBe(1);
+    // the applied paragraph is NOT also emitted as a word-merged changed block
+    expect(html).not.toContain("<del>brown</del>"); // no double-render of the change as a baseline diff
+  });
+
+  test("renderReview keeps author coloring aligned on a block AFTER a length-changing pending proposal (INV-49/50)", () => {
+    // block 1 has a pending proposal whose applied text is MUCH LONGER than its
+    // original; block 2 carries a Claude authorship span (in currentText coords).
+    const baseline = "one short.\n\ntwo stable here.\n";
+    const current = "one MUCH LONGER REPLACED TEXT.\n\ntwo stable here.\n";
+    const proposals: ProposalView[] = [{
+      id: "pr_1",
+      anchorStart: current.indexOf("one MUCH LONGER REPLACED TEXT."),
+      anchorEnd: current.indexOf("one MUCH LONGER REPLACED TEXT.") + "one MUCH LONGER REPLACED TEXT.".length,
+      replaced: "one short.",
+      replacement: "one MUCH LONGER REPLACED TEXT.",
+      original: "one short.",
+    }];
+    const sStart = current.indexOf("stable");
+    const authorSpans = [{ start: sStart, end: sStart + "stable".length, author: "claude" as const }];
+    const html = renderReview(baseline, current, authorSpans, proposals);
+    // the Claude coloring wraps "stable" exactly — not shifted by the proposal's length delta.
+    expect(html).toMatch(/<span class="cw-by-claude">stable<\/span>/);
+  });
+
+  test("proposalBlockHtml renders Accept/Reject controls with dropdown carets (#64)", () => {
+    const html = renderReview("a\n", "b\n", [], [
+      { id: "pr_1", anchorStart: 0, anchorEnd: 1, replaced: "a", replacement: "b" },
+    ]);
+    expect(html).toMatch(/data-action="accept"/);
+    expect(html).toMatch(/data-action="reject"/);
+    expect(html).toMatch(/data-action="acceptAll"/);
+    expect(html).toMatch(/data-action="rejectAll"/);
+    expect(html).toMatch(/Accept/);
+    expect(html).toMatch(/Reject/);
+  });
 });
 
 import { renderTrackChanges as rtc2 } from "../src/trackChangesModel";