Add Perflint rules to ruff.

pyproject.toml

@@ -240,6 +240,8 @@ extend-select = [
     "ISC",
     # flake8-logging
     "LOG",
+    # Perflint
+    "PERF",
     # pygrep-hooks
     "PGH",
     # flake8-pie
@@ -314,6 +316,8 @@ ignore = [
     "D402",
     # First word of the first line should be properly capitalized
     "D403",
+    # `try`-`except` within a loop incurs performance overhead
+    "PERF203",
     # Use of `assert` detected; needed for mypy
     "S101",
     # FTP-related functions are being called; https://github.com/scrapy/scrapy/issues/4180

scrapy/utils/asyncgen.py

@@ -7,10 +7,7 @@ _T = TypeVar("_T")
 
 
 async def collect_asyncgen(result: AsyncIterable[_T]) -> list[_T]:
-    results = []
-    async for x in result:
-        results.append(x)
-    return results
+    return [x async for x in result]
 
 
 async def as_async_generator(

scrapy/utils/python.py

@@ -235,8 +235,7 @@ def get_func_args(func: Callable[..., Any], stripself: bool = False) -> list[str
                 continue
             args.append(name)
     else:
-        for name in sig.parameters.keys():
-            args.append(name)
+        args = list(sig.parameters)
 
     if stripself and args and args[0] == "self":
         args = args[1:]

tests/test_feedexport.py

@@ -1757,13 +1757,13 @@ class FeedPostProcessedExportsTest(FeedExportTestBase):
                 crawler = get_crawler(spider_cls, settings)
                 yield crawler.crawl()
 
-            for file_path, feed_options in FEEDS.items():
+            for file_path in FEEDS:
                 content[str(file_path)] = (
                     Path(file_path).read_bytes() if Path(file_path).exists() else None
                 )
 
         finally:
-            for file_path in FEEDS.keys():
+            for file_path in FEEDS:
                 if not Path(file_path).exists():
                     continue
 

tests/test_spidermiddleware.py

@@ -289,10 +289,7 @@ class ProcessSpiderOutputNonIterableMiddleware:
 
 class ProcessSpiderOutputCoroutineMiddleware:
     async def process_spider_output(self, response, result, spider):
-        results = []
-        for r in result:
-            results.append(r)
-        return results
+        return result
 
 
 class ProcessSpiderOutputInvalidResult(BaseAsyncSpiderMiddlewareTestCase):

tests/test_utils_asyncgen.py

@@ -8,9 +8,7 @@ class AsyncgenUtilsTest(unittest.TestCase):
     @deferred_f_from_coro_f
     async def test_as_async_generator(self):
         ag = as_async_generator(range(42))
-        results = []
-        async for i in ag:
-            results.append(i)
+        results = [i async for i in ag]
         self.assertEqual(results, list(range(42)))
 
     @deferred_f_from_coro_f

tests/test_utils_iterators.py

@@ -26,15 +26,14 @@ class XmliterBaseTestCase:
         """
 
         response = XmlResponse(url="http://example.com", body=body)
-        attrs = []
-        for x in self.xmliter(response, "product"):
-            attrs.append(
-                (
-                    x.attrib["id"],
-                    x.xpath("name/text()").getall(),
-                    x.xpath("./type/text()").getall(),
-                )
+        attrs = [
+            (
+                x.attrib["id"],
+                x.xpath("name/text()").getall(),
+                x.xpath("./type/text()").getall(),
             )
+            for x in self.xmliter(response, "product")
+        ]
 
         self.assertEqual(
             attrs, [("001", ["Name 1"], ["Type 1"]), ("002", ["Name 2"], ["Type 2"])]
@@ -99,15 +98,14 @@ class XmliterBaseTestCase:
             # Unicode body needs encoding information
             XmlResponse(url="http://example.com", body=body, encoding="utf-8"),
         ):
-            attrs = []
-            for x in self.xmliter(r, "þingflokkur"):
-                attrs.append(
-                    (
-                        x.attrib["id"],
-                        x.xpath("./skammstafanir/stuttskammstöfun/text()").getall(),
-                        x.xpath("./tímabil/fyrstaþing/text()").getall(),
-                    )
+            attrs = [
+                (
+                    x.attrib["id"],
+                    x.xpath("./skammstafanir/stuttskammstöfun/text()").getall(),
+                    x.xpath("./tímabil/fyrstaþing/text()").getall(),
                 )
+                for x in self.xmliter(r, "þingflokkur")
+            ]
 
             self.assertEqual(
                 attrs,

tests/test_utils_python.py

@@ -58,13 +58,6 @@ class MutableAsyncChainTest(unittest.TestCase):
         for i in range(5, 7):
             yield i
 
-    @staticmethod
-    async def collect_asyncgen_exc(asyncgen):
-        results = []
-        async for x in asyncgen:
-            results.append(x)
-        return results
-
     @deferred_f_from_coro_f
     async def test_mutableasyncchain(self):
         m = MutableAsyncChain(self.g1(), as_async_generator(range(3, 7)))