Merge pull request #259 from openzim/fix_js_import_rewrite

Add JS rewriting rule to ignore import function rewriting

Author: benoit74

CHANGELOG.md

@@ -10,6 +10,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Upgrade to wombat 3.8.11 (#256)
+- Backport changes in wabac.js around JS rewriting rules (#259)
+
+### Fixed
+
+- JS rewriting abusively rewrite import function (#255)
 
 ## [5.1.1] - 2025-02-17
 

src/zimscraperlib/rewriting/js.py

@@ -154,13 +154,15 @@ def create_js_rules() -> list[TransformationRule]:
     return [
         # rewriting `eval(...)` - invocation
         (re.compile(r"(?:^|\s)\beval\s*\("), replace_prefix_from(eval_str, "eval")),
+        (re.compile(r"\([\w]+,\s*eval\)\("), m2str(lambda _: f" {eval_str}")),
         # rewriting `x = eval` - no invocation
         (re.compile(r"[=]\s*\beval\b(?![(:.$])"), replace("eval", "self.eval")),
+        (re.compile(r"var\s+self"), replace("var", "let")),
         # rewriting `.postMessage` -> `__WB_pmw(self).postMessage`
         (re.compile(r"\.postMessage\b\("), add_prefix(".__WB_pmw(self)")),
         # rewriting `location = ` to custom expression `(...).href =` assignement
         (
-            re.compile(r"[^$.]?\s?\blocation\b\s*[=]\s*(?![\s\d=])"),
+            re.compile(r"(?:^|[^$.+*/%^-])\s?\blocation\b\s*[=]\s*(?![\s\d=])"),
             add_suffix_non_prop(check_loc),
         ),
         # rewriting `return this`
@@ -186,6 +188,7 @@ def create_js_rules() -> list[TransformationRule]:
         # As the rule will match first, it will prevent next rule matching `import` to
         # be apply to `async import`.
         (re.compile(r"async\s+import\s*\("), m2str(lambda x: x)),
+        (re.compile(r"[^$.]\bimport\s*\([^)]*\)\s*\{"), m2str(lambda x: x)),
         # esm dynamic import, if found, mark as module
         (
             re.compile(r"[^$.]\bimport\s*\("),

tests/rewriting/test_js_rewriting.py

@@ -101,6 +101,40 @@ def test_js_rewrite_post_message(simple_js_rewriter: JsRewriter):
     )
 
 
+@pytest.mark.parametrize(
+    "raw_js,expected",
+    [
+        pytest.param("x = eval; x(a);", "x = self.eval; x(a);", id="case1"),
+        pytest.param(
+            " eval(a)",
+            " WB_wombat_runEval2((_______eval_arg, isGlobal) => { var ge = eval; "
+            "return isGlobal ? ge(_______eval_arg) : eval(_______eval_arg); })"
+            ".eval(this, (function() { return arguments })(),a)",
+            id="case2",
+        ),
+        pytest.param(
+            "$eval = eval; $eval(a);", "$eval = self.eval; $eval(a);", id="case3"
+        ),
+        pytest.param(
+            "foo(a, eval(data));",
+            "foo(a, WB_wombat_runEval2((_______eval_arg, isGlobal) => { var ge = eval; "
+            "return isGlobal ? ge(_______eval_arg) : eval(_______eval_arg); })"
+            ".eval(this, (function() { return arguments })(),data));",
+            id="case4",
+        ),
+        pytest.param(
+            "return(1, eval)(data);",
+            "return WB_wombat_runEval2((_______eval_arg, isGlobal) => { var ge = eval; "
+            "return isGlobal ? ge(_______eval_arg) : eval(_______eval_arg); })"
+            ".eval(this, (function() { return arguments })(),data);",
+            id="case5",
+        ),
+    ],
+)
+def test_js_rewrite_evals(simple_js_rewriter: JsRewriter, raw_js: str, expected: str):
+    assert simple_js_rewriter.rewrite(raw_js) == expected
+
+
 class WrappedTestContent(ContentForTests):
 
     def __init__(
@@ -173,11 +207,20 @@ def wrap_script(text: str) -> str:
             input_="this. location = 'http://example.com/'",
             expected="this. location = 'http://example.com/'",
         ),
+        WrappedTestContent(
+            input_="abc-location = http://example.com/",
+            expected="abc-location = http://example.com/",
+        ),
+        WrappedTestContent(
+            input_="func(location = 0)",
+            expected="func(location = 0)",
+        ),
         WrappedTestContent(
             input_="if (self.foo) { console.log('blah') }",
             expected="if (self.foo) { console.log('blah') }",
         ),
         WrappedTestContent(input_="window.x = 5", expected="window.x = 5"),
+        WrappedTestContent(input_=" var    self  ", expected=" let    self  "),
     ]
 )
 def rewrite_wrapped_content(request: pytest.FixtureRequest):
@@ -271,6 +314,12 @@ def wrap_import(text: str) -> str:
 import { Z } from "../../../path.js";
 
 B = await import(somefile);
+
+class X {
+  import(a, b, c) {
+    await import (somefile);
+  }
+}
 """,
             expected="""
 import * from "../../../example.com/file.js"
@@ -282,6 +331,12 @@ def wrap_import(text: str) -> str:
 import { Z } from "../../path.js";
 
 B = await ____wb_rewrite_import__(import.meta.url, somefile);
+
+class X {
+  import(a, b, c) {
+    await ____wb_rewrite_import__ (import.meta.url, somefile);
+  }
+}
 """,
         ),
         ImportTestContent(
@@ -341,6 +396,7 @@ def test_import_rewrite(rewrite_import_content: ImportTestContent):
         "a.window.x = 5",
         "  postMessage({'a': 'b'})",
         "simport(5);",
+        "import(e) {",
         "a.import(5);",
         "$import(5);",
         "async import(val) { ... }",