comments: Address UUID + other comments

Author: dmadisetti

frontend/src/utils/__tests__/local-variables.test.ts

@@ -24,7 +24,26 @@ describe("unmangleLocal", () => {
   it("returns null for non-mangled strings", () => {
     expect(unmangleLocal("just_a_variable")).toBeNull();
     expect(unmangleLocal("_private")).toBeNull();
-    expect(unmangleLocal("_cell_Hbol_")).toBeNull();
+  });
+
+  it("handles the single-underscore local", () => {
+    // `_` is a valid local name (variables.py:62-63), mangling to
+    // `_cell_<id>_` with no trailing suffix.
+    expect(unmangleLocal("_cell_Hbol_")).toEqual({
+      cellId: "Hbol",
+      name: "_",
+    });
+  });
+
+  it("handles UUID-style cell ids", () => {
+    // External / VSCode notebooks use `external_prefix()` which is a
+    // `uuid4()` (hyphenated).
+    expect(
+      unmangleLocal("_cell_c9bf9e57-1685-4c89-bafb-ff5af830be8a_a"),
+    ).toEqual({
+      cellId: "c9bf9e57-1685-4c89-bafb-ff5af830be8a",
+      name: "_a",
+    });
   });
 
   it("does not match marimo cell file paths", () => {
@@ -67,6 +86,39 @@ describe("splitMangledLocals", () => {
     const path = "/tmp/marimo_42/__marimo__cell_Hbol_.py";
     expect(splitMangledLocals(path)).toEqual([path]);
   });
+
+  it("ignores `_cell_...` substrings preceded by `_`", () => {
+    // Mirrors `(?<!_)` in `variables.py`: a leading `_` (e.g. inside
+    // `__marimo__cell_<id>_<...>`) means this is not a mangle the compiler
+    // produced, so we must not demangle it.
+    const text = "see __marimo__cell_Hbol_a for details";
+    expect(splitMangledLocals(text)).toEqual([text]);
+  });
+
+  it("splits a UUID-style cell id", () => {
+    expect(
+      splitMangledLocals(
+        "name '_cell_c9bf9e57-1685-4c89-bafb-ff5af830be8a_a' is not defined",
+      ),
+    ).toEqual([
+      "name '",
+      {
+        cellId: "c9bf9e57-1685-4c89-bafb-ff5af830be8a",
+        name: "_a",
+      },
+      "' is not defined",
+    ]);
+  });
+
+  it("splits the single-underscore local", () => {
+    expect(
+      splitMangledLocals("name '_cell_Hbol_' is not defined"),
+    ).toEqual([
+      "name '",
+      { cellId: "Hbol", name: "_" },
+      "' is not defined",
+    ]);
+  });
 });
 
 describe("containsMangledLocal", () => {
@@ -81,4 +133,8 @@ describe("containsMangledLocal", () => {
       containsMangledLocal("/tmp/marimo_42/__marimo__cell_Hbol_.py"),
     ).toBe(false);
   });
+
+  it("ignores `_cell_...` substrings preceded by `_`", () => {
+    expect(containsMangledLocal("see __marimo__cell_Hbol_a")).toBe(false);
+  });
 });

frontend/src/utils/local-variables.ts

@@ -11,18 +11,15 @@ import type { CellId } from "@/core/cells/ids";
  * Mirrors `marimo/_ast/variables.py`.
  */
 
-// Matches `_cell_<cell_id><name>` where the cell id has no underscores and
-// `<name>` begins with `_` (the original ref was a local underscore name).
-// Python mangle is `f"_cell_{cell_id}{ref}"` (variables.py:41), so the only
-// `_` between the id and the name is the leading `_` of the name itself.
-// Non-greedy id group + name group that must start with `_` correctly
-// recovers the boundary.
-//
-// Anchored on a single leading `_cell_`, so the compiled cell file path
-// `__marimo__cell_<id>_.py` (two leading underscores, no trailing `_<name>`)
-// does not match.
-const MANGLED_LOCAL_PATTERN = String.raw`_cell_([^\W_]\w*?)(_\w+)`;
-const ANCHORED_RE = new RegExp(`^${MANGLED_LOCAL_PATTERN}$`);
+// Matches `_cell_<cell_id><name>` for normal ids and UUIDs. The `[\w-]`
+// id class admits hyphens; the `_\w*` name group admits the bare `_`
+// local; the `(?<!_)` lookbehind skips `__marimo__cell_...` paths.
+// Mirrors `_MANGLED_LOCAL_IN_TEXT_RE` in `variables.py`.
+const MANGLED_LOCAL_BODY = String.raw`_cell_([^\W_][\w-]*?)(_\w*)`;
+const MANGLED_LOCAL_PATTERN = String.raw`(?<!_)${MANGLED_LOCAL_BODY}`;
+// Strict (whole-string) form for `unmangleLocal`; the leading `^` makes the
+// lookbehind trivially satisfied, so use the bare body.
+const ANCHORED_RE = new RegExp(`^${MANGLED_LOCAL_BODY}$`);
 const UNANCHORED_RE = new RegExp(MANGLED_LOCAL_PATTERN);
 const GLOBAL_RE = new RegExp(MANGLED_LOCAL_PATTERN, "g");
 

marimo/_ast/variables.py

@@ -71,10 +71,10 @@ def get_cell_from_local(
 
 
 # Demangle every occurrence of `_cell_<cell_id><_name>` inside a free-form
-# string (test output, traceback lines, etc.) back to `<_name>`. The
-# negative-lookbehind excludes the compiled cell-file path
-# `__marimo__cell_<id>_.py`, which carries a leading `_` we must not strip.
-_MANGLED_LOCAL_IN_TEXT_RE = re.compile(r"(?<!_)_cell_\w+?(_\w+)")
+# string (test output, traceback lines, etc.) back to `<_name>`. Matches
+# normal ids and UUIDs; the `(?<!_)` lookbehind skips the compiled cell-file
+# path `__marimo__cell_<id>_.py`, which carries a leading `_`.
+_MANGLED_LOCAL_IN_TEXT_RE = re.compile(r"(?<!_)_cell_(?:[^\W_][\w-]*?)(_\w*)")
 
 
 def demangle_locals_in_text(text: str) -> str:

tests/_ast/test_variables.py

@@ -6,7 +6,9 @@
 
 def test_demangle_in_name_error_message() -> None:
     assert (
-        demangle_locals_in_text("NameError: name '_cell_vblA_a' is not defined")
+        demangle_locals_in_text(
+            "NameError: name '_cell_vblA_a' is not defined"
+        )
         == "NameError: name '_a' is not defined"
     )
 
@@ -25,3 +27,25 @@ def test_demangle_leaves_cell_file_path_alone() -> None:
 
 def test_demangle_no_op_for_plain_text() -> None:
     assert demangle_locals_in_text("plain text") == "plain text"
+
+
+def test_demangle_handles_uuid_cell_id() -> None:
+    # External / VSCode notebooks use `external_prefix()` (a uuid4) as the
+    # cell-id prefix, producing hyphenated mangles.
+    assert (
+        demangle_locals_in_text(
+            "NameError: name "
+            "'_cell_c9bf9e57-1685-4c89-bafb-ff5af830be8a_a' "
+            "is not defined"
+        )
+        == "NameError: name '_a' is not defined"
+    )
+
+
+def test_demangle_handles_single_underscore_local() -> None:
+    # `_` is a valid local name (variables.py:is_local); it mangles to
+    # `_cell_<id>_` with no name suffix.
+    assert (
+        demangle_locals_in_text("NameError: name '_cell_Hbol_' is not defined")
+        == "NameError: name '_' is not defined"
+    )