Tighten import handling and fix SetComprehension typo (#9607)

Author: manzt

frontend/src/core/codemirror/go-to-definition/__tests__/commands.test.ts

@@ -253,6 +253,73 @@ a = 10`;
     `);
   });
 
+  test("from-import alias is the binding, not the imported name", async () => {
+    const code = `\
+from math import sin as my_sin
+print(my_sin)`;
+    view = createEditor(code);
+    const usagePosition = code.lastIndexOf("my_sin");
+    const result = goToVariableDefinition(view, "my_sin", usagePosition);
+
+    expect(result).toBe(true);
+    await tick();
+    // The alias `my_sin` (after `as`) is the real binding.
+    expect(renderEditorView(view)).toMatchInlineSnapshot(`
+      "
+      from math import sin as my_sin
+                              ^
+      print(my_sin)
+      "
+    `);
+  });
+
+  test("module path in from-import is not a local definition", async () => {
+    const code = `\
+from math import sin
+print(math)`;
+    view = createEditor(code);
+    const usagePosition = code.lastIndexOf("math");
+    // `math` is a module reference in the from-clause, not a binding in this
+    // cell, so the scoped resolver should return false and let the caller fall
+    // through to cross-cell resolution.
+    const result = goToVariableDefinition(view, "math", usagePosition);
+
+    expect(result).toBe(false);
+    expect(view.state.selection.main.head).toBe(0);
+  });
+
+  test("imported name without `as` is a local definition", async () => {
+    const code = `\
+from math import sin
+print(sin)`;
+    view = createEditor(code);
+    const usagePosition = code.lastIndexOf("sin");
+    const result = goToVariableDefinition(view, "sin", usagePosition);
+
+    expect(result).toBe(true);
+    await tick();
+    expect(renderEditorView(view)).toMatchInlineSnapshot(`
+      "
+      from math import sin
+                       ^
+      print(sin)
+      "
+    `);
+  });
+
+  test("imported name shadowed by `as` is not a binding", async () => {
+    const code = `\
+from math import sin as my_sin
+print(sin)`;
+    view = createEditor(code);
+    const usagePosition = code.lastIndexOf("sin");
+    // `sin` here refers to nothing in this cell (it was renamed to `my_sin`),
+    // so the scoped resolver should return false.
+    const result = goToVariableDefinition(view, "sin", usagePosition);
+
+    expect(result).toBe(false);
+  });
+
   test("selects outer-scope function declaration", async () => {
     view = createEditor(`\
 def x():

frontend/src/core/codemirror/go-to-definition/__tests__/utils.test.ts

@@ -133,4 +133,51 @@ output = _x + 10`;
     await tick();
     expect(view.state.selection.main.head).toBe(code.indexOf("_x = 10"));
   });
+
+  test("falls through to cross-cell when in-cell occurrence is only a module path in a from-import", async () => {
+    // Regression: ImportStatement used to register every VariableName child
+    // (the module path and pre-`as` names) as in-cell declarations, so the
+    // local-first short-circuit would steal F12 from cross-cell resolution.
+    const moduleCell = cellId("module-cell");
+    const usageCell = cellId("usage-cell");
+    const moduleCode = `mymodule = 100`;
+    const usageCode = `\
+from mymodule import something
+print(mymodule)`;
+
+    const moduleView = createEditor(moduleCode, moduleCode.length);
+    const usageView = createEditor(
+      usageCode,
+      usageCode.lastIndexOf("mymodule"),
+    );
+    views.push(moduleView, usageView);
+
+    const notebook = initialNotebookState();
+    notebook.cellHandles[moduleCell] = {
+      current: { editorView: moduleView, editorViewOrNull: moduleView },
+    } as never;
+    notebook.cellHandles[usageCell] = {
+      current: { editorView: usageView, editorViewOrNull: usageView },
+    } as never;
+
+    store.set(notebookAtom, notebook);
+    store.set(variablesAtom, {
+      [variableName("mymodule")]: {
+        dataType: "int",
+        declaredBy: [moduleCell],
+        name: variableName("mymodule"),
+        usedBy: [usageCell],
+        value: "100",
+      },
+    });
+
+    const result = goToDefinitionAtCursorPosition(usageView);
+
+    expect(result).toBe(true);
+    await tick();
+    // Cross-cell jump: moduleView's cursor should land on `mymodule = 100`.
+    expect(moduleView.state.selection.main.head).toBe(
+      moduleCode.indexOf("mymodule"),
+    );
+  });
 });

frontend/src/core/codemirror/go-to-definition/commands.ts

@@ -307,33 +307,52 @@ function collectMatchingDeclarations(
       break;
     }
     case "ImportStatement": {
+      // The grammar emits one ImportStatement for both `import x [as y]` and
+      // `from m import x [as y], ...`. Direct children include the keywords
+      // (`from`/`import`/`as`), commas, dots, and every VariableName from the
+      // module path AND the import list. We only want the names that actually
+      // bind in the current scope: the post-`as` alias if present, otherwise
+      // the imported name itself. Names before `import` (the from-path) and
+      // the original name when an alias follows it are NOT bindings.
       const subCursor = node.cursor();
       subCursor.firstChild();
-      do {
-        if (
-          subCursor.name === "VariableName" &&
-          state.doc.sliceString(subCursor.from, subCursor.to) === variableName
-        ) {
-          addDeclaration(declarations, currentScope, subCursor.from);
+      let pastImport = false;
+      // Buffer the most recent post-`import` VariableName so we can defer
+      // committing it until we know whether `as` follows.
+      let pending: { from: number; matches: boolean } | null = null;
+      const commit = () => {
+        if (pending?.matches) {
+          addDeclaration(declarations, currentScope, pending.from);
         }
-      } while (subCursor.nextSibling());
-      break;
-    }
-    case "ImportFromStatement": {
-      const subCursor = node.cursor();
-      subCursor.firstChild();
-      let foundImport = false;
+        pending = null;
+      };
       do {
         if (subCursor.name === "import") {
-          foundImport = true;
-        } else if (
-          foundImport &&
-          subCursor.name === "VariableName" &&
-          state.doc.sliceString(subCursor.from, subCursor.to) === variableName
-        ) {
-          addDeclaration(declarations, currentScope, subCursor.from);
+          pastImport = true;
+          continue;
+        }
+        if (!pastImport) {
+          continue;
+        }
+        if (subCursor.name === "as") {
+          // Next VariableName is the alias and replaces `pending`.
+          pending = null;
+          continue;
+        }
+        if (subCursor.name === "VariableName") {
+          // Flush any previous pending name (no `as` followed it).
+          commit();
+          pending = {
+            from: subCursor.from,
+            matches:
+              state.doc.sliceString(subCursor.from, subCursor.to) ===
+              variableName,
+          };
+        } else if (subCursor.name === ",") {
+          commit();
         }
       } while (subCursor.nextSibling());
+      commit();
       break;
     }
     case "TryStatement":
@@ -410,23 +429,21 @@ function findScopedDefinitionPosition(
  * @param view The editor view which contains the variable name.
  * @param variableName The name of the variable to select, if found in the editor.
  * @param usagePosition The position of the variable usage, if available.
- * @param fallbackToFirstMatch Whether to fall back to the first matching
- * variable name when no scoped definition is found. Defaults to true.
  */
 export function goToVariableDefinition(
   view: EditorView,
   variableName: string,
   usagePosition?: number,
-  fallbackToFirstMatch = true,
 ): boolean {
   const { state } = view;
-  let from: number | null = null;
-  if (usagePosition !== undefined) {
-    from = findScopedDefinitionPosition(state, variableName, usagePosition);
-  }
-  if (from === null && fallbackToFirstMatch) {
-    from = findFirstMatchingVariable(state, variableName);
-  }
+  // When the caller knows the usage position, trust the scoped lookup. Falling
+  // back to first-match would defeat the local-vs-cross-cell decision in
+  // goToDefinition: if the symbol only appears as a module path in an import,
+  // scoped resolution returns null and we want the caller to try other cells.
+  const from =
+    usagePosition !== undefined
+      ? findScopedDefinitionPosition(state, variableName, usagePosition)
+      : findFirstMatchingVariable(state, variableName);
 
   if (from === null) {
     return false;

frontend/src/core/codemirror/go-to-definition/utils.ts

@@ -82,7 +82,6 @@ export function goToDefinition(
       view,
       variableName,
       usagePosition,
-      false,
     );
     if (foundLocally) {
       return true;

frontend/src/core/codemirror/reactive-references/__tests__/analyzer.test.ts

@@ -640,6 +640,60 @@ def run(polars):
     `);
   });
 
+  test("set comprehension target shadows outer global", () => {
+    // Regression: SCOPE_CREATING_NODES used "SetComprehension" instead of the
+    // grammar's "SetComprehensionExpression", so set comprehensions never
+    // created a scope and their for-target was treated as reactive.
+    expect(runHighlight(["x"], "result = {x for x in range(5)}"))
+      .toMatchInlineSnapshot(`
+      "
+      result = {x for x in range(5)}
+      "
+    `);
+  });
+
+  test("from-import module path stays reactive", () => {
+    // Regression: ImportStatement collected every VariableName child, so the
+    // module name in `from m import y` was wrongly treated as a local binding.
+    expect(
+      runHighlight(
+        ["math"],
+        `
+def f():
+    from math import sin as my_sin
+    return math + my_sin(1)`,
+      ),
+    ).toMatchInlineSnapshot(`
+      "
+      def f():
+          from math import sin as my_sin
+          return math + my_sin(1)
+                 ^^^^
+      "
+    `);
+  });
+
+  test("from-import: aliased imported name is not a binding", () => {
+    // Regression: `sin` in `from math import sin as my_sin` was incorrectly
+    // registered as a local binding, hiding genuine reactive uses of `sin`.
+    expect(
+      runHighlight(
+        ["sin"],
+        `
+def f():
+    from math import sin as my_sin
+    return sin + my_sin(1)`,
+      ),
+    ).toMatchInlineSnapshot(`
+      "
+      def f():
+          from math import sin as my_sin
+          return sin + my_sin(1)
+                 ^^^
+      "
+    `);
+  });
+
   test("lambda inside function with outer global", () => {
     expect(
       runHighlight(