test(editor): pin remote-delete cursor contract + correct scope docblock (#196 review round 1)

- F2: add a remap test for a REMOTE (meta-less) delete of a cursor's own range,
  pinning the collapse-not-drop contract — the deleted-over cursor collapses to a
  zero-width caret at the deletion point and stays in the set; others keep their
  occurrence (this is the riskiest remap path, previously covered only for insert).
- F1: reword the out-of-scope docblock — occurrences inside tables/code-blocks/
  callouts ARE matched and edited as plain text (no schema-aware cursor); they
  were never a 'deliberately not built' boundary.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/client/src/features/editor/extensions/extensions.ts

@@ -45,6 +45,7 @@ import {
   TiptapPdf,
   PageBreak,
   SearchAndReplace,
+  MultiCursor,
   Mention,
   TableDndExtension,
   TableHandleCommandsExtension,
@@ -447,6 +448,10 @@ export const mainExtensions = [
       };
     },
   }).configure(),
+  // Multi-cursor editing (MVP / Variant A): select-all-occurrences + type into
+  // all at once. Does not depend on collaboration, so it lives in mainExtensions
+  // (available in both the plain and collaborative editors).
+  MultiCursor,
   Columns,
   Column,
   AutoJoiner.configure({

apps/client/src/features/editor/styles/index.css

@@ -1,5 +1,6 @@
 @import "./core.css";
 @import "./collaboration.css";
+@import "./multi-cursor.css";
 @import "./task-list.css";
 @import "./placeholder.css";
 @import "./drag-handle.css";

apps/client/src/features/editor/styles/multi-cursor.css

@@ -0,0 +1,60 @@
+/*
+ * Multi-cursor (issue #196). Deliberately DISTINCT from the collaboration
+ * carets (collaboration.css) so a user never confuses their own multi-cursors
+ * with a co-author's caret: solid accent-blue carets + a translucent blue
+ * range highlight, versus the thin dark collaboration caret with a name label.
+ */
+
+/* A secondary caret rendered as a Decoration.widget at each cursor position. */
+.multi-cursor__caret {
+    position: relative;
+    display: inline-block;
+    width: 0;
+    height: 1em;
+    vertical-align: text-bottom;
+    pointer-events: none;
+}
+
+.multi-cursor__caret::after {
+    content: "";
+    position: absolute;
+    left: -1px;
+    top: 0;
+    bottom: 0;
+    width: 2px;
+    background: #2b6cb0;
+    animation: multi-cursor-blink 1s steps(1) infinite;
+}
+
+/* Optional label class reserved for future per-cursor annotations. */
+.multi-cursor__label {
+    position: absolute;
+    top: -1.4em;
+    left: -1px;
+    font-size: 0.7rem;
+    line-height: normal;
+    padding: 0.05rem 0.25rem;
+    border-radius: 3px 3px 3px 0;
+    background: #2b6cb0;
+    color: #fff;
+    white-space: nowrap;
+    user-select: none;
+    pointer-events: none;
+}
+
+/* Inline highlight for a multi-cursor RANGE (from < to). */
+.multi-cursor__selection {
+    background: rgba(43, 108, 176, 0.28);
+    border-radius: 2px;
+}
+
+@keyframes multi-cursor-blink {
+    0%,
+    50% {
+        opacity: 1;
+    }
+    51%,
+    100% {
+        opacity: 0;
+    }
+}

packages/editor-ext/src/index.ts

@@ -20,6 +20,7 @@ export * from "./lib/html-embed/html-embed";
 export * from "./lib/mention";
 export * from "./lib/markdown";
 export * from "./lib/search-and-replace";
+export * from "./lib/multi-cursor";
 export * from "./lib/embed-provider";
 export * from "./lib/subpages";
 export * from "./lib/transclusion";

packages/editor-ext/src/lib/multi-cursor/index.ts

@@ -0,0 +1,3 @@
+import { MultiCursor } from "./multi-cursor";
+export * from "./multi-cursor";
+export default MultiCursor;

packages/editor-ext/src/lib/multi-cursor/multi-cursor.test.ts

@@ -0,0 +1,453 @@
+import { describe, it, expect } from "vitest";
+import { Editor } from "@tiptap/core";
+import { Document } from "@tiptap/extension-document";
+import { Paragraph } from "@tiptap/extension-paragraph";
+import { Text } from "@tiptap/extension-text";
+import { Bold } from "@tiptap/extension-bold";
+import { Node as PMNode } from "@tiptap/pm/model";
+import { MultiCursor, multiCursorPluginKey, MAX_CURSORS } from "./multi-cursor";
+import { findOccurrences } from "../search-and-replace/find-occurrences";
+
+const extensions = [Document, Paragraph, Text, Bold, MultiCursor];
+
+function makeEditor(content?: any) {
+  return new Editor({
+    extensions,
+    content: content ?? { type: "doc", content: [{ type: "paragraph" }] },
+  });
+}
+
+function doc(...paragraphs: string[]) {
+  return {
+    type: "doc",
+    content: paragraphs.map((text) => ({
+      type: "paragraph",
+      content: text ? [{ type: "text", text }] : [],
+    })),
+  };
+}
+
+function paraTexts(d: PMNode): string[] {
+  const out: string[] = [];
+  d.forEach((node) => {
+    if (node.type.name === "paragraph") out.push(node.textContent);
+  });
+  return out;
+}
+
+function cursors(editor: Editor) {
+  return multiCursorPluginKey.getState(editor.state)!.cursors;
+}
+
+// Simulate typing a character through the real handleTextInput routing (the
+// browser path). someMethod-equivalent: dispatch a DOM-ish text input by calling
+// the view's input handler directly.
+function typeText(editor: Editor, text: string) {
+  const { from, to } = editor.state.selection;
+  // props.handleTextInput is what ProseMirror calls on beforeinput/keypress.
+  const handled = editor.view.someProp(
+    "handleTextInput",
+    (fn) => fn(editor.view, from, to, text) || false,
+  );
+  if (!handled) {
+    // Fall back to a normal insertion (no active multi-cursor set).
+    editor.view.dispatch(editor.state.tr.insertText(text, from, to));
+  }
+}
+
+function pressKey(editor: Editor, key: string) {
+  editor.view.someProp("handleKeyDown", (fn) =>
+    fn(editor.view, new KeyboardEvent("keydown", { key })),
+  );
+}
+
+describe("multi-cursor: selectAllOccurrences", () => {
+  it("finds EVERY occurrence of a repeated word under the cursor", () => {
+    const editor = makeEditor(doc("foo bar foo baz foo"));
+    // Cursor inside the first "foo".
+    editor.commands.setTextSelection(2);
+    expect(editor.commands.selectAllOccurrences()).toBe(true);
+
+    const cs = cursors(editor);
+    expect(cs.length).toBe(3);
+    // Every cursor spans a "foo".
+    for (const c of cs) {
+      expect(editor.state.doc.textBetween(c.from, c.to)).toBe("foo");
+    }
+    editor.destroy();
+  });
+
+  it("uses the current non-empty selection as the term", () => {
+    const editor = makeEditor(doc("ab abc ab abcd ab"));
+    // Select the first "ab".
+    editor.commands.setTextSelection({ from: 1, to: 3 });
+    expect(editor.state.doc.textBetween(1, 3)).toBe("ab");
+    editor.commands.selectAllOccurrences();
+    // Literal substring match (selection is not whole-word), so every "ab"
+    // including those inside "abc"/"abcd" is matched: 5 total.
+    const cs = cursors(editor);
+    expect(cs.length).toBe(5);
+    editor.destroy();
+  });
+
+  it("whole-word matching from a word cursor does not match substrings", () => {
+    const editor = makeEditor(doc("cat category cat scatter cat"));
+    editor.commands.setTextSelection(2); // inside first "cat"
+    editor.commands.selectAllOccurrences();
+    // Only the three standalone "cat" words, not "category"/"scatter".
+    expect(cursors(editor).length).toBe(3);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: mass typing (single transaction)", () => {
+  it("types text into N carets at once", () => {
+    const editor = makeEditor(doc("foo foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(3);
+
+    // Typing replaces each selected "foo" with "X".
+    typeText(editor, "X");
+    expect(paraTexts(editor.state.doc)).toEqual(["X X X"]);
+
+    // The cursors are now carets right after each inserted "X".
+    const cs = cursors(editor);
+    expect(cs.length).toBe(3);
+    for (const c of cs) expect(c.from).toBe(c.to);
+    editor.destroy();
+  });
+
+  it("continues typing at the resulting carets (append semantics)", () => {
+    const editor = makeEditor(doc("a a a"));
+    editor.commands.setTextSelection(1);
+    editor.commands.selectAllOccurrences();
+    typeText(editor, "b"); // each "a" -> "b"
+    typeText(editor, "c"); // append at each caret -> "bc"
+    expect(paraTexts(editor.state.doc)).toEqual(["bc bc bc"]);
+    editor.destroy();
+  });
+
+  it("applies the whole multi-edit in a SINGLE transaction (one undo step)", () => {
+    // "One Cmd/Ctrl+Z undoes the whole multi-edit" holds iff the N edits land in
+    // ONE transaction (history groups by transaction). @tiptap/extension-history
+    // is not a dependency here, so rather than exercise undo we assert the
+    // property that guarantees it: typing into N cursors is exactly ONE dispatch.
+    const editor = makeEditor(doc("foo foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(3);
+
+    const orig = editor.view.dispatch.bind(editor.view);
+    let dispatches = 0;
+    editor.view.dispatch = (tr) => {
+      dispatches += 1;
+      return orig(tr);
+    };
+    typeText(editor, "Z");
+    editor.view.dispatch = orig;
+
+    expect(dispatches).toBe(1); // all three edits share one transaction
+    expect(paraTexts(editor.state.doc)).toEqual(["Z Z Z"]);
+    editor.destroy();
+  });
+
+  it("off-by-one guard: reverse-order iteration keeps every position valid", () => {
+    // If the mass edit iterated FORWARD, inserting at an earlier cursor would
+    // shift every later cursor and corrupt the result. Different-length
+    // replacement makes such a bug visible.
+    const editor = makeEditor(doc("x x x x"));
+    editor.commands.setTextSelection(1);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(4);
+    typeText(editor, "LONG");
+    expect(paraTexts(editor.state.doc)).toEqual(["LONG LONG LONG LONG"]);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: mass Backspace / Delete", () => {
+  it("Backspace removes one char before each caret", () => {
+    const editor = makeEditor(doc("foo foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    // Collapse selections to carets at the END of each "foo" by typing then
+    // removing is complex; instead type to convert ranges into carets first.
+    typeText(editor, "ab"); // each "foo" -> "ab", carets after "ab"
+    expect(paraTexts(editor.state.doc)).toEqual(["ab ab ab"]);
+    pressKey(editor, "Backspace"); // remove the trailing "b" at each caret
+    expect(paraTexts(editor.state.doc)).toEqual(["a a a"]);
+    editor.destroy();
+  });
+
+  it("Delete removes one char after each caret", () => {
+    const editor = makeEditor(doc("fooX fooX"));
+    // Literal (selection) match of "foo" -> both occurrences inside "fooX".
+    editor.commands.setTextSelection({ from: 1, to: 4 }); // first "foo"
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    typeText(editor, "foo"); // rewrite "foo", carets now sit before each "X"
+    expect(paraTexts(editor.state.doc)).toEqual(["fooX fooX"]);
+    pressKey(editor, "Delete"); // remove the "X" after each caret
+    expect(paraTexts(editor.state.doc)).toEqual(["foo foo"]);
+    editor.destroy();
+  });
+
+  it("Backspace at a block-start caret is a no-op for that cursor", () => {
+    const editor = makeEditor(doc("ab", "ab"));
+    // Select both "ab" then convert to carets at start by replacing with "".
+    editor.commands.setTextSelection({ from: 1, to: 3 }); // first "ab"
+    editor.commands.selectAllOccurrences();
+    // Move carets to block start: type "" is not possible; instead delete range.
+    pressKey(editor, "Backspace"); // deletes each selected "ab"
+    expect(paraTexts(editor.state.doc)).toEqual(["", ""]);
+    // Carets are now at each block start; another Backspace must not throw and
+    // must not merge blocks (still two empty paragraphs).
+    pressKey(editor, "Backspace");
+    expect(paraTexts(editor.state.doc)).toEqual(["", ""]);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: addNextOccurrence (Cmd/Ctrl+D)", () => {
+  it("first press selects the current word, next press adds the next", () => {
+    const editor = makeEditor(doc("go go go"));
+    editor.commands.setTextSelection(2); // inside first "go"
+    editor.commands.addNextOccurrence();
+    expect(cursors(editor).length).toBe(1);
+    editor.commands.addNextOccurrence();
+    expect(cursors(editor).length).toBe(2);
+    editor.commands.addNextOccurrence();
+    expect(cursors(editor).length).toBe(3);
+    // Nothing left to add — stays at 3.
+    editor.commands.addNextOccurrence();
+    expect(cursors(editor).length).toBe(3);
+    for (const c of cursors(editor)) {
+      expect(editor.state.doc.textBetween(c.from, c.to)).toBe("go");
+    }
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: position remapping", () => {
+  it("remaps cursors after a LOCAL edit before them", () => {
+    const editor = makeEditor(doc("foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    const before = cursors(editor).map((c) => ({ ...c }));
+
+    // Insert unrelated text at the very start (pos 1), shifting everything +5.
+    editor.view.dispatch(editor.state.tr.insertText("HELLO", 1));
+
+    const after = cursors(editor);
+    expect(after.length).toBe(before.length);
+    for (let i = 0; i < after.length; i += 1) {
+      expect(after[i].from).toBe(before[i].from + 5);
+      expect(after[i].to).toBe(before[i].to + 5);
+      // And they still point at "foo".
+      expect(editor.state.doc.textBetween(after[i].from, after[i].to)).toBe(
+        "foo",
+      );
+    }
+    editor.destroy();
+  });
+
+  it("remaps cursors after a simulated REMOTE edit (ordinary transaction)", () => {
+    const editor = makeEditor(doc("foo bar foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    const before = cursors(editor).map((c) => ({ ...c }));
+    expect(before.length).toBe(2);
+
+    // y-prosemirror applies remote changes as ordinary transactions. Emulate a
+    // remote insertion between the two "foo"s (inside "bar", pos 6) with a tr
+    // that carries NO multi-cursor meta — exactly like a collaborator's edit.
+    const tr = editor.state.tr.insertText("ZZ", 6);
+    editor.view.dispatch(tr);
+
+    const after = cursors(editor);
+    // The first "foo" (before the insertion) is unchanged; the second shifts +2.
+    expect(after[0].from).toBe(before[0].from);
+    expect(after[1].from).toBe(before[1].from + 2);
+    for (const c of after) {
+      expect(editor.state.doc.textBetween(c.from, c.to)).toBe("foo");
+    }
+    editor.destroy();
+  });
+
+  it("a REMOTE delete UNDER a cursor collapses it to a caret (not drop), leaving others intact", () => {
+    // The riskiest remap path: a collaborator deletes the very text one cursor
+    // spans. Both edges map with assoc +1 and there is no drop logic, so the
+    // deleted-over cursor CONTRACT is: it collapses to a zero-width caret at the
+    // deletion point (from === to) and STAYS in the set — it is not removed.
+    // Untouched cursors keep spanning their occurrence. Pinning this makes the
+    // collapse-not-drop choice explicit (review #372 F2).
+    const editor = makeEditor(doc("foo bar foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    const before = cursors(editor).map((c) => ({ ...c }));
+    expect(before.length).toBe(2);
+
+    // Remote (no multi-cursor meta) delete of the FIRST "foo" range.
+    const tr = editor.state.tr.delete(before[0].from, before[0].to);
+    editor.view.dispatch(tr);
+
+    const after = cursors(editor);
+    // Still two cursors — the deleted-over one is NOT dropped.
+    expect(after.length).toBe(2);
+    // The first collapsed to a caret at the deletion point.
+    expect(after[0].from).toBe(after[0].to);
+    expect(after[0].from).toBe(before[0].from);
+    // The second still spans "foo" (shifted left by the 3 removed chars).
+    expect(after[1].from).toBe(before[1].from - 3);
+    expect(editor.state.doc.textBetween(after[1].from, after[1].to)).toBe("foo");
+    // Sanity: the document now reads " bar foo".
+    expect(paraTexts(editor.state.doc)).toEqual([" bar foo"]);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: collapse / exit", () => {
+  it("exitMultiCursor clears the set", () => {
+    const editor = makeEditor(doc("foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    editor.commands.exitMultiCursor();
+    expect(cursors(editor).length).toBe(0);
+    editor.destroy();
+  });
+
+  it("an arrow key collapses the set", () => {
+    const editor = makeEditor(doc("foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    pressKey(editor, "ArrowRight");
+    expect(cursors(editor).length).toBe(0);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: collapse on composition / mousedown", () => {
+  // Invoke a plugin handleDOMEvents handler through the real prop plumbing.
+  function fireDOM(editor: Editor, name: string): void {
+    editor.view.someProp("handleDOMEvents", (handlers: any) => {
+      const h = handlers && handlers[name];
+      if (h) h(editor.view, new Event(name));
+      return false;
+    });
+  }
+
+  it("collapses the set on compositionstart (IME) — MVP does not multi-IME", () => {
+    const editor = makeEditor(doc("foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    fireDOM(editor, "compositionstart");
+    expect(cursors(editor).length).toBe(0);
+    editor.destroy();
+  });
+
+  it("collapses the set on a plain mousedown (VS Code behaviour)", () => {
+    const editor = makeEditor(doc("foo foo"));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    fireDOM(editor, "mousedown");
+    expect(cursors(editor).length).toBe(0);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: hard cap", () => {
+  it("never activates more than MAX_CURSORS cursors", () => {
+    const many = new Array(MAX_CURSORS + 20).fill("w").join(" ");
+    const editor = makeEditor(doc(many));
+    editor.commands.setTextSelection(2);
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(MAX_CURSORS);
+    editor.destroy();
+  });
+});
+
+describe("multi-cursor: marks are carried across a mass edit", () => {
+  it("preserves marks spanning each replaced range", () => {
+    const editor = makeEditor({
+      type: "doc",
+      content: [
+        {
+          type: "paragraph",
+          content: [
+            { type: "text", text: "a " },
+            { type: "text", marks: [{ type: "bold" }], text: "key" },
+            { type: "text", text: " b " },
+            { type: "text", marks: [{ type: "bold" }], text: "key" },
+          ],
+        },
+      ],
+    });
+    editor.commands.setTextSelection(3); // inside first bold "key"
+    editor.commands.selectAllOccurrences();
+    expect(cursors(editor).length).toBe(2);
+    typeText(editor, "NEW");
+
+    // Both replacements keep the bold mark.
+    let boldRuns = 0;
+    editor.state.doc.descendants((node) => {
+      if (
+        node.isText &&
+        node.text === "NEW" &&
+        node.marks.some((m) => m.type.name === "bold")
+      ) {
+        boldRuns += 1;
+      }
+    });
+    expect(boldRuns).toBe(2);
+    editor.destroy();
+  });
+});
+
+// The extracted find-occurrences util must return the SAME occurrences that the
+// old inline walk produced (and that search-and-replace still relies on).
+describe("find-occurrences util", () => {
+  it("finds all matches of a literal regex across text nodes", () => {
+    const editor = makeEditor(doc("foo foofoo foo"));
+    const results = findOccurrences(editor.state.doc, /foo/gu);
+    // 4 occurrences: two standalone + two inside "foofoo".
+    expect(results.length).toBe(4);
+    for (const r of results) {
+      expect(editor.state.doc.textBetween(r.from, r.to)).toBe("foo");
+    }
+    editor.destroy();
+  });
+
+  it("ignores whitespace-only matches and empty regex", () => {
+    const editor = makeEditor(doc("a b c"));
+    expect(findOccurrences(editor.state.doc, null as any).length).toBe(0);
+    // A whitespace regex yields no results (matches are trimmed away).
+    expect(findOccurrences(editor.state.doc, /\s/gu).length).toBe(0);
+    editor.destroy();
+  });
+
+  it("finds a match spanning two differently-marked contiguous text nodes", () => {
+    const editor = makeEditor({
+      type: "doc",
+      content: [
+        {
+          type: "paragraph",
+          content: [
+            { type: "text", text: "wo" },
+            { type: "text", marks: [{ type: "bold" }], text: "rd" },
+          ],
+        },
+      ],
+    });
+    const results = findOccurrences(editor.state.doc, /word/gu);
+    expect(results.length).toBe(1);
+    expect(editor.state.doc.textBetween(results[0].from, results[0].to)).toBe(
+      "word",
+    );
+    editor.destroy();
+  });
+});

packages/editor-ext/src/lib/multi-cursor/multi-cursor.ts

@@ -0,0 +1,545 @@
+import { Extension, Range } from "@tiptap/core";
+import { Decoration, DecorationSet, EditorView } from "@tiptap/pm/view";
+import {
+  Plugin,
+  PluginKey,
+  TextSelection,
+  type EditorState,
+} from "@tiptap/pm/state";
+import { Mark } from "@tiptap/pm/model";
+import { findOccurrences } from "../search-and-replace/find-occurrences";
+
+/**
+ * Multi-cursor editing — MVP (issue #196, "Variant A").
+ *
+ * VS Code-style multi-cursor limited to "select all occurrences of a word (or
+ * the current selection) and type into all of them at once", built ON TOP OF
+ * the search-and-replace mass-transaction machinery:
+ *
+ *   - Cmd/Ctrl+Shift+L (selectAllOccurrences): the word under the cursor (or the
+ *     current non-empty selection) -> ALL its occurrences become active cursors.
+ *   - Cmd/Ctrl+D (addNextOccurrence): add the NEXT occurrence of the term.
+ *   - Typing / Backspace / Delete apply to EVERY active cursor in ONE
+ *     transaction (so a single Cmd/Ctrl+Z undoes the whole multi-edit).
+ *   - Esc (exitMultiCursor): collapse back to a single cursor.
+ *
+ * The single-transaction, reverse-order edit mechanic mirrors `replaceAll` in
+ * search-and-replace.ts: we iterate cursors from the END of the document to the
+ * START so an earlier edit never invalidates a later position, carrying the
+ * marks that span each range.
+ *
+ * CONSCIOUS v1 OUT-OF-SCOPE BOUNDARIES (these are "Variant B", deliberately NOT
+ * built here):
+ *   - Alt+Click arbitrary carets and Alt+drag column selection.
+ *   - Cmd/Ctrl+Alt+Up/Down "add cursor on the adjacent line".
+ *   - Simultaneous IME / composition input into multiple positions — on
+ *     `compositionstart` we collapse back to a single cursor.
+ *   - Cursors spanning different schema nodes in one edit.
+ *
+ * NOT out of scope, but worth stating precisely: there is NO schema-aware or
+ * structural cursor. Occurrences are found by a plain text-node walk
+ * (`findOccurrences`), so a term that appears inside a table cell, code block or
+ * callout DOES get a cursor there and IS edited — as plain text, exactly like
+ * `replaceAll`. There is no special table/code handling; the per-cursor try/catch
+ * only SKIPS a cursor whose edit would violate the schema (never applied
+ * half-way), it does not exclude those node types from matching.
+ */
+
+interface MultiCursorState {
+  // Each active cursor: a caret when from === to, a range when from < to.
+  cursors: Range[];
+}
+
+export const multiCursorPluginKey = new PluginKey<MultiCursorState>(
+  "multiCursor",
+);
+
+// Hard safety cap on simultaneously-active cursors — stop adding past it.
+export const MAX_CURSORS = 100;
+
+export interface MultiCursorStorage {
+  // Whether the active term matches whole words only. Set to true when the set
+  // was seeded from a bare cursor (word under caret), false when seeded from an
+  // explicit selection (literal substring match, like VS Code). Remembered so
+  // addNextOccurrence keeps matching the same way as selectAllOccurrences.
+  wholeWord: boolean;
+}
+
+declare module "@tiptap/core" {
+  interface Storage {
+    multiCursor: MultiCursorStorage;
+  }
+  interface Commands<ReturnType> {
+    multiCursor: {
+      /** Select all occurrences of the word/selection as active cursors. */
+      selectAllOccurrences: () => ReturnType;
+      /** Add the next occurrence of the current term to the cursor set. */
+      addNextOccurrence: () => ReturnType;
+      /** Collapse the multi-cursor set back to a single cursor. */
+      exitMultiCursor: () => ReturnType;
+    };
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Term helpers
+// ---------------------------------------------------------------------------
+
+function escapeRegExp(s: string): string {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+// A "word" is a run of letters/numbers/underscore; those get whole-word
+// matching (\b…\b) so a term never matches inside a larger word. Anything else
+// (punctuation, phrases) is matched literally. Case-sensitive, like VS Code.
+function isWordTerm(s: string): boolean {
+  return /^[\p{L}\p{N}_]+$/u.test(s);
+}
+
+// wholeWord uses \b…\b so the term never matches inside a larger word; it only
+// applies to word-like terms (a term containing punctuation cannot be
+// whole-word-bounded meaningfully). Otherwise the term is matched literally.
+function buildTermRegex(term: string, wholeWord: boolean): RegExp {
+  const esc = escapeRegExp(term);
+  return wholeWord && isWordTerm(term)
+    ? new RegExp(`\\b${esc}\\b`, "gu")
+    : new RegExp(esc, "gu");
+}
+
+// Word under a position: returns the exact { from, to } range and its text, or
+// null if the position is not inside a word in a textblock.
+function getWordAt(
+  state: EditorState,
+  pos: number,
+): { from: number; to: number; text: string } | null {
+  const $pos = state.doc.resolve(pos);
+  const parent = $pos.parent;
+  if (!parent.isTextblock) return null;
+
+  const text = parent.textContent;
+  const offset = $pos.parentOffset;
+  const start = $pos.start();
+  const wordRe = /[\p{L}\p{N}_]+/gu;
+
+  let m: RegExpExecArray | null;
+  while ((m = wordRe.exec(text)) !== null) {
+    const s = m.index;
+    const e = m.index + m[0].length;
+    if (offset >= s && offset <= e) {
+      return { from: start + s, to: start + e, text: m[0] };
+    }
+  }
+  return null;
+}
+
+// ---------------------------------------------------------------------------
+// Plugin-state access
+// ---------------------------------------------------------------------------
+
+function getCursors(state: EditorState): Range[] {
+  const st = multiCursorPluginKey.getState(state);
+  return st ? st.cursors : [];
+}
+
+function setCursors(view: EditorView, cursors: Range[]): void {
+  view.dispatch(view.state.tr.setMeta(multiCursorPluginKey, cursors));
+}
+
+function collapse(view: EditorView): void {
+  setCursors(view, []);
+}
+
+// ---------------------------------------------------------------------------
+// The single-transaction, reverse-order mass edit (mirrors replaceAll)
+// ---------------------------------------------------------------------------
+
+interface EditOp {
+  from: number;
+  to: number;
+  // Text to insert at `from` after deleting [from, to); "" for a pure delete.
+  text: string;
+}
+
+/**
+ * Apply one edit per cursor in ONE transaction. Ops are processed from the END
+ * of the document to the START so an earlier edit never shifts a later position
+ * (mirrors `replaceAll`). Each cursor is wrapped independently: a schema
+ * violation SKIPS that one cursor instead of throwing away the whole
+ * transaction, so the document is never left half-applied.
+ *
+ * After building the transaction the new cursor positions are recomputed by
+ * mapping each op's original anchor through `tr.mapping` (which also remaps any
+ * concurrent changes), so carets land right after their inserted text.
+ */
+function dispatchMassEdit(view: EditorView, ops: EditOp[]): boolean {
+  if (!ops.length) return false;
+
+  const { state } = view;
+  const tr = state.tr;
+  const schema = state.schema;
+
+  // Ascending by `from`; iterate reverse so earlier positions stay valid.
+  const sorted = [...ops].sort((a, b) => a.from - b.from);
+  const appliedLen: number[] = new Array(sorted.length).fill(0);
+
+  for (let i = sorted.length - 1; i >= 0; i -= 1) {
+    const { from, to, text } = sorted[i];
+    try {
+      let marks: readonly Mark[] = [];
+      if (text) {
+        if (to > from) {
+          // Carry all marks spanning the replaced range.
+          const set = new Set<Mark>();
+          tr.doc.nodesBetween(from, to, (node) => {
+            if (node.isText && node.marks) {
+              node.marks.forEach((mk) => set.add(mk));
+            }
+          });
+          marks = Array.from(set);
+        } else {
+          // Caret: continue the marks active at the insertion point.
+          marks = state.storedMarks || state.doc.resolve(from).marks();
+        }
+      }
+
+      // ONE atomic step per cursor: replaceWith covers both insert (from === to)
+      // and replace (to > from); a pure delete (empty text) uses delete. This
+      // can never leave a cursor half-applied (deleted but not re-inserted) the
+      // way a separate delete-then-insert pair could if the insert step threw.
+      if (text) {
+        tr.replaceWith(from, to, schema.text(text, marks as Mark[]));
+      } else if (to > from) {
+        tr.delete(from, to);
+      }
+
+      appliedLen[i] = text.length;
+    } catch {
+      // Per-cursor backstop (text-only MVP): drop this cursor's edit, keep the
+      // rest of the transaction intact.
+      appliedLen[i] = 0;
+    }
+  }
+
+  if (!tr.docChanged) return false;
+
+  // Recompute cursor carets from the ORIGINAL op anchors through the full map.
+  const newCursors: Range[] = sorted.map((op, i) => {
+    const start = tr.mapping.map(op.from, -1);
+    const caret = start + appliedLen[i];
+    return { from: caret, to: caret };
+  });
+
+  tr.setMeta(multiCursorPluginKey, newCursors);
+
+  // Park the native selection on the last caret so the browser draws exactly
+  // one real caret; the rest are our decoration widgets.
+  const last = newCursors[newCursors.length - 1];
+  tr.setSelection(TextSelection.create(tr.doc, last.from));
+
+  view.dispatch(tr);
+  return true;
+}
+
+function buildDeleteOps(
+  state: EditorState,
+  cursors: Range[],
+  forward: boolean,
+): EditOp[] {
+  return cursors.map((c) => {
+    // A selected range: Backspace/Delete removes the whole range.
+    if (c.to > c.from) return { from: c.from, to: c.to, text: "" };
+
+    const $pos = state.doc.resolve(c.from);
+    if (forward) {
+      // Delete: at the end of a textblock there is nothing to remove (a no-op;
+      // MVP does not merge blocks across a multi-cursor set).
+      if ($pos.parentOffset >= $pos.parent.content.size) {
+        return { from: c.from, to: c.from, text: "" };
+      }
+      return { from: c.from, to: c.from + 1, text: "" };
+    }
+    // Backspace: at the start of a textblock there is nothing to remove.
+    if ($pos.parentOffset <= 0) {
+      return { from: c.from, to: c.from, text: "" };
+    }
+    return { from: c.from - 1, to: c.from, text: "" };
+  });
+}
+
+// ---------------------------------------------------------------------------
+// Extension
+// ---------------------------------------------------------------------------
+
+export const MultiCursor = Extension.create<unknown, MultiCursorStorage>({
+  name: "multiCursor",
+
+  addStorage() {
+    return { wholeWord: true };
+  },
+
+  addCommands() {
+    return {
+      selectAllOccurrences:
+        () =>
+        ({ editor, state, tr, dispatch }) => {
+          let term: string;
+          // A bare cursor expands to the whole word; an explicit selection is
+          // matched literally (VS Code semantics).
+          const wholeWord = state.selection.empty;
+          if (wholeWord) {
+            const word = getWordAt(state, state.selection.from);
+            if (!word) return false;
+            term = word.text;
+          } else {
+            term = state.doc.textBetween(
+              state.selection.from,
+              state.selection.to,
+            );
+          }
+          if (!term.trim()) return false;
+          editor.storage.multiCursor.wholeWord = wholeWord;
+
+          const results = findOccurrences(
+            state.doc,
+            buildTermRegex(term, wholeWord),
+          ).slice(0, MAX_CURSORS);
+          if (!results.length) return false;
+
+          if (dispatch) {
+            tr.setMeta(multiCursorPluginKey, results);
+            const last = results[results.length - 1];
+            tr.setSelection(TextSelection.create(tr.doc, last.from, last.to));
+            dispatch(tr);
+          }
+          return true;
+        },
+
+      addNextOccurrence:
+        () =>
+        ({ editor, state, tr, dispatch }) => {
+          const existing = getCursors(state);
+          let cursors: Range[];
+
+          if (!existing.length) {
+            // First press: turn the current word/selection into the one cursor.
+            let range: Range;
+            const wholeWord = state.selection.empty;
+            if (wholeWord) {
+              const word = getWordAt(state, state.selection.from);
+              if (!word) return false;
+              range = { from: word.from, to: word.to };
+            } else {
+              range = { from: state.selection.from, to: state.selection.to };
+            }
+            editor.storage.multiCursor.wholeWord = wholeWord;
+            cursors = [range];
+          } else {
+            // Subsequent press: add the next unselected occurrence of the term,
+            // matched the SAME way (whole-word vs literal) the set was seeded.
+            if (existing.length >= MAX_CURSORS) return true;
+
+            const first = existing[0];
+            const term = state.doc.textBetween(first.from, first.to);
+            if (!term.trim()) return false;
+
+            const results = findOccurrences(
+              state.doc,
+              buildTermRegex(term, editor.storage.multiCursor.wholeWord),
+            );
+            const keys = new Set(existing.map((c) => `${c.from}:${c.to}`));
+            const notSelected = results.filter(
+              (r) => !keys.has(`${r.from}:${r.to}`),
+            );
+            if (!notSelected.length) return true; // all occurrences selected
+
+            const maxTo = Math.max(...existing.map((c) => c.to));
+            const next =
+              notSelected.find((r) => r.from >= maxTo) || notSelected[0];
+            cursors = [...existing, next];
+          }
+
+          if (dispatch) {
+            tr.setMeta(multiCursorPluginKey, cursors);
+            const last = cursors[cursors.length - 1];
+            tr.setSelection(TextSelection.create(tr.doc, last.from, last.to));
+            dispatch(tr);
+          }
+          return true;
+        },
+
+      exitMultiCursor:
+        () =>
+        ({ tr, dispatch }) => {
+          if (dispatch) {
+            tr.setMeta(multiCursorPluginKey, []);
+            dispatch(tr);
+          }
+          return true;
+        },
+    };
+  },
+
+  addKeyboardShortcuts() {
+    return {
+      "Mod-Shift-l": () => {
+        this.editor.commands.selectAllOccurrences();
+        // Always consume so the browser's default is prevented.
+        return true;
+      },
+      "Mod-d": () => {
+        this.editor.commands.addNextOccurrence();
+        // Consume unconditionally to prevent the browser's Cmd/Ctrl+D bookmark.
+        return true;
+      },
+      Escape: () => {
+        // Only swallow Escape while a multi-cursor set is active; otherwise let
+        // Escape keep its other behaviours (e.g. closing dialogs).
+        if (!getCursors(this.editor.state).length) return false;
+        return this.editor.commands.exitMultiCursor();
+      },
+    };
+  },
+
+  addProseMirrorPlugins() {
+    return [
+      new Plugin<MultiCursorState>({
+        key: multiCursorPluginKey,
+
+        state: {
+          init: () => ({ cursors: [] }),
+          apply(tr, value): MultiCursorState {
+            // A command (or a mass edit) can set/clear the cursor set directly.
+            // Its cursors are already in the post-transaction coordinate space,
+            // so they take priority over remapping.
+            const meta = tr.getMeta(multiCursorPluginKey) as
+              | Range[]
+              | undefined;
+            if (meta !== undefined) {
+              return { cursors: meta.slice(0, MAX_CURSORS) };
+            }
+
+            if (!value.cursors.length) return value;
+
+            // Remap surviving cursors across ANY doc change — this covers both
+            // local edits and REMOTE Yjs edits (y-prosemirror applies remote
+            // changes as ordinary transactions, so mapping them here keeps every
+            // multi-cursor correctly positioned without special-casing collab).
+            if (tr.docChanged) {
+              // Map both edges with the SAME association (+1) so content
+              // inserted at a boundary shifts the whole cursor right and a caret
+              // (from === to) can never invert into a range.
+              const cursors = value.cursors.map((c) => ({
+                from: tr.mapping.map(c.from, 1),
+                to: tr.mapping.map(c.to, 1),
+              }));
+              return { cursors };
+            }
+
+            return value;
+          },
+        },
+
+        props: {
+          decorations(state) {
+            const st = multiCursorPluginKey.getState(state);
+            if (!st || !st.cursors.length) return DecorationSet.empty;
+
+            const decorations: Decoration[] = [];
+            st.cursors.forEach((c, i) => {
+              if (c.from === c.to) {
+                decorations.push(
+                  Decoration.widget(
+                    c.from,
+                    () => {
+                      const el = document.createElement("span");
+                      el.className = "multi-cursor__caret";
+                      return el;
+                    },
+                    { side: 0, key: `mc-caret-${i}` },
+                  ),
+                );
+              } else {
+                decorations.push(
+                  Decoration.inline(c.from, c.to, {
+                    class: "multi-cursor__selection",
+                  }),
+                );
+              }
+            });
+
+            return DecorationSet.create(state.doc, decorations);
+          },
+
+          handleTextInput(view, _from, _to, text) {
+            const cursors = getCursors(view.state);
+            if (!cursors.length) return false;
+
+            // Insert `text` at EVERY cursor in one transaction. Returning true
+            // prevents ProseMirror's own single-position insert at the native
+            // selection, so there is no double-insert there.
+            const ops = cursors.map((c) => ({
+              from: c.from,
+              to: c.to,
+              text,
+            }));
+            return dispatchMassEdit(view, ops);
+          },
+
+          handleKeyDown(view, event) {
+            const cursors = getCursors(view.state);
+            if (!cursors.length) return false;
+
+            if (event.key === "Backspace") {
+              dispatchMassEdit(view, buildDeleteOps(view.state, cursors, false));
+              return true;
+            }
+            if (event.key === "Delete") {
+              dispatchMassEdit(view, buildDeleteOps(view.state, cursors, true));
+              return true;
+            }
+
+            // Let modifier combinations (our own shortcuts, copy, etc.) through
+            // WITHOUT collapsing the set.
+            if (event.metaKey || event.ctrlKey || event.altKey) return false;
+
+            // Navigation / block keys collapse back to a single cursor, then let
+            // ProseMirror handle the movement on the native selection.
+            const COLLAPSE_KEYS = [
+              "ArrowLeft",
+              "ArrowRight",
+              "ArrowUp",
+              "ArrowDown",
+              "Home",
+              "End",
+              "PageUp",
+              "PageDown",
+              "Enter",
+              "Tab",
+            ];
+            if (COLLAPSE_KEYS.includes(event.key)) {
+              collapse(view);
+              return false;
+            }
+
+            return false;
+          },
+
+          handleDOMEvents: {
+            // A plain click exits multi-cursor (VS Code behaviour).
+            mousedown: (view) => {
+              if (getCursors(view.state).length) collapse(view);
+              return false;
+            },
+            // MVP does not drive multi-position IME — collapse on composition.
+            compositionstart: (view) => {
+              if (getCursors(view.state).length) collapse(view);
+              return false;
+            },
+          },
+        },
+      }),
+    ];
+  },
+});
+
+export default MultiCursor;

packages/editor-ext/src/lib/search-and-replace/find-occurrences.ts

@@ -0,0 +1,69 @@
+import { Range } from "@tiptap/core";
+import { Node as PMNode } from "@tiptap/pm/model";
+
+interface TextNodesWithPosition {
+  text: string;
+  pos: number;
+}
+
+/**
+ * Shared "find all occurrences of a term in the doc" primitive.
+ *
+ * Walks every text node of the document and returns each regex match as a
+ * `{ from, to }` range. Contiguous text nodes (which may differ only by marks)
+ * are concatenated into a single run, so a match that spans e.g. "wo" + bold
+ * "rd" is still found; runs are split by any non-text node, so a match never
+ * crosses a node boundary. Whitespace-only matches are ignored.
+ *
+ * This is used by BOTH search-and-replace (highlight/replace) and multi-cursor
+ * (turn occurrences into active cursors) so the two stay behaviourally in sync.
+ * Extracted verbatim from the original `processSearches` walk.
+ */
+export function findOccurrences(doc: PMNode, searchTerm: RegExp): Range[] {
+  const results: Range[] = [];
+
+  if (!searchTerm) return results;
+
+  let textNodesWithPosition: TextNodesWithPosition[] = [];
+  let index = 0;
+
+  doc?.descendants((node, pos) => {
+    if (node.isText) {
+      if (textNodesWithPosition[index]) {
+        textNodesWithPosition[index] = {
+          text: textNodesWithPosition[index].text + node.text,
+          pos: textNodesWithPosition[index].pos,
+        };
+      } else {
+        textNodesWithPosition[index] = {
+          text: `${node.text}`,
+          pos,
+        };
+      }
+    } else {
+      index += 1;
+    }
+  });
+
+  textNodesWithPosition = textNodesWithPosition.filter(Boolean);
+
+  for (const element of textNodesWithPosition) {
+    const { text, pos } = element;
+    const matches = Array.from(text.matchAll(searchTerm)).filter(
+      ([matchText]) => matchText.trim(),
+    );
+
+    for (const m of matches) {
+      if (m[0] === "") break;
+
+      if (m.index !== undefined) {
+        results.push({
+          from: pos + m.index,
+          to: pos + m.index + m[0].length,
+        });
+      }
+    }
+  }
+
+  return results;
+}

packages/editor-ext/src/lib/search-and-replace/index.ts

@@ -1,3 +1,4 @@
 import { SearchAndReplace } from './search-and-replace'
 export * from './search-and-replace'
+export * from './find-occurrences'
 export default SearchAndReplace

packages/editor-ext/src/lib/search-and-replace/search-and-replace.ts

@@ -29,6 +29,7 @@ import {
   type Transaction,
 } from "@tiptap/pm/state";
 import { Node as PMNode, Mark } from "@tiptap/pm/model";
+import { findOccurrences } from "./find-occurrences";
 
 declare module "@tiptap/core" {
   interface Storage {
@@ -76,11 +77,6 @@ declare module "@tiptap/core" {
   }
 }
 
-interface TextNodesWithPosition {
-  text: string;
-  pos: number;
-}
-
 const getRegex = (
   s: string,
   disableRegex: boolean,
@@ -104,10 +100,6 @@ function processSearches(
   resultIndex: number,
 ): ProcessedSearches {
   const decorations: Decoration[] = [];
-  const results: Range[] = [];
-
-  let textNodesWithPosition: TextNodesWithPosition[] = [];
-  let index = 0;
 
   if (!searchTerm) {
     return {
@@ -116,43 +108,8 @@ function processSearches(
     };
   }
 
-  doc?.descendants((node, pos) => {
+  // Shared find-all-occurrences primitive (also used by multi-cursor).
-    if (node.isText) {
+  const results: Range[] = findOccurrences(doc, searchTerm);
-      if (textNodesWithPosition[index]) {
-        textNodesWithPosition[index] = {
-          text: textNodesWithPosition[index].text + node.text,
-          pos: textNodesWithPosition[index].pos,
-        };
-      } else {
-        textNodesWithPosition[index] = {
-          text: `${node.text}`,
-          pos,
-        };
-      }
-    } else {
-      index += 1;
-    }
-  });
-
-  textNodesWithPosition = textNodesWithPosition.filter(Boolean);
-
-  for (const element of textNodesWithPosition) {
-    const { text, pos } = element;
-    const matches = Array.from(text.matchAll(searchTerm)).filter(
-      ([matchText]) => matchText.trim(),
-    );
-
-    for (const m of matches) {
-      if (m[0] === "") break;
-
-      if (m.index !== undefined) {
-        results.push({
-          from: pos + m.index,
-          to: pos + m.index + m[0].length,
-        });
-      }
-    }
-  }
 
   for (let i = 0; i < results.length; i += 1) {
     const r = results[i];