Disallow passing functions/mixins across compilations (#2053)

Co-authored-by: Natalie Weizenbaum <[email protected]>

Author: ntkme

js-api-spec/value/function.test.ts

@@ -80,3 +80,45 @@ describe('rejects a function signature that', () => {
   it('has no closing parenthesis', () => rejectsSignature('foo('));
   it('has a non-identifier name', () => rejectsSignature('$foo()'));
 });
+
+it('rejects a compiler function from a different compilation', () => {
+  let plusOne: Value | undefined;
+  compileString(
+    `
+      @use 'sass:meta';
+
+      @function plusOne($n) {@return $n + 1}
+      a {b: meta.call(foo(meta.get-function('plusOne')), 2)}
+    `,
+    {
+      functions: {
+        'foo($arg)': (args: Value[]) => {
+          plusOne = args[0];
+          return plusOne;
+        },
+      },
+    }
+  );
+
+  let plusTwo;
+  expect(() => {
+    compileString(
+      `
+        @use 'sass:meta';
+
+        @function plusTwo($n) {@return $n + 2}
+        a {b: meta.call(foo(meta.get-function('plusTwo')), 2)}
+      `,
+      {
+        functions: {
+          'foo($arg)': (args: Value[]) => {
+            plusTwo = args[0];
+            return plusOne!;
+          },
+        },
+      }
+    );
+  }).toThrowSassException({line: 4});
+
+  expect(plusOne).not.toEqual(plusTwo);
+});

js-api-spec/value/mixin.test.ts

@@ -2,7 +2,7 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import {SassMixin, compileString} from 'sass';
+import {SassMixin, compileString, Value} from 'sass';
 
 import {spy} from '../utils';
 
@@ -44,3 +44,54 @@ it('can round-trip a mixin reference from Sass', () => {
 
   expect(fn).toHaveBeenCalled();
 });
+
+it('rejects a compiler mixin from a different compilation', () => {
+  let a: Value | undefined;
+  compileString(
+    `
+      @use 'sass:meta';
+
+      @mixin a() {
+        a {
+          b: c;
+        }
+      }
+
+      @include meta.apply(foo(meta.get-mixin('a')));
+    `,
+    {
+      functions: {
+        'foo($arg)': (args: Value[]) => {
+          a = args[0];
+          return a;
+        },
+      },
+    }
+  );
+
+  let b;
+  expect(() => {
+    compileString(
+      `
+        @use 'sass:meta';
+
+        @mixin b() {
+          c {
+            d: e;
+          }
+        }
+        @include meta.apply(foo(meta.get-mixin('b')));
+      `,
+      {
+        functions: {
+          'foo($arg)': (args: Value[]) => {
+            b = args[0];
+            return a!;
+          },
+        },
+      }
+    );
+  }).toThrowSassException({line: 8});
+
+  expect(a).not.toEqual(b);
+});