Report crawl errors in scrapy check

scrapy/commands/check.py

@@ -1,10 +1,14 @@
 import argparse
+import asyncio
 import time
 from collections import defaultdict
-from collections.abc import AsyncIterator
+from collections.abc import AsyncIterator, Awaitable
 from typing import Any, ClassVar
+from unittest import TestCase, TextTestRunner
 from unittest import TextTestResult as _TextTestResult
-from unittest import TextTestRunner
+
+from twisted.internet.defer import Deferred
+from twisted.python.failure import Failure
 
 from scrapy import Spider
 from scrapy.commands import ScrapyCommand
@@ -42,6 +46,41 @@ class TextTestResult(_TextTestResult):
             write("\n")
 
 
+def _report_crawl_errors(
+    crawl: Awaitable[None], spidername: str, result: TextTestResult
+) -> None:
+    """Make an exception that stops *crawl* before its contracts can run show
+    up as an error in *result*, instead of being silently discarded."""
+
+    class CrawlTestCase(TestCase):
+        def runTest(self) -> None:
+            pass
+
+        def __str__(self) -> str:
+            return f"[{spidername}] crawl"
+
+    def report(exception: BaseException) -> None:
+        result.addError(
+            CrawlTestCase(),
+            (type(exception), exception, exception.__traceback__),  # type: ignore[arg-type]
+        )
+
+    if isinstance(crawl, Deferred):
+
+        def on_failure(failure: Failure) -> None:
+            assert failure.value is not None
+            report(failure.value)
+
+        crawl.addErrback(on_failure)
+    elif isinstance(crawl, asyncio.Task):
+
+        def on_done(task: asyncio.Task[None]) -> None:
+            if not task.cancelled() and (exception := task.exception()) is not None:
+                report(exception)
+
+        crawl.add_done_callback(on_done)
+
+
 class Command(ScrapyCommand):
     requires_project = True
     default_settings: ClassVar[dict[str, Any]] = {"LOG_ENABLED": False}
@@ -100,7 +139,8 @@ class Command(ScrapyCommand):
                     for method in tested_methods:
                         contract_reqs[spidercls.name].append(method)
                 elif tested_methods:
-                    self.crawler_process.crawl(spidercls)
+                    crawl = self.crawler_process.crawl(spidercls)
+                    _report_crawl_errors(crawl, spidercls.name, result)
 
             # start checks
             if opts.list:

tests/test_command_check.py

@@ -6,6 +6,8 @@ from typing import TYPE_CHECKING
 from unittest import TestCase
 from unittest.mock import MagicMock, Mock, PropertyMock, call, patch
 
+import pytest
+
 from scrapy.commands.check import Command, TextTestResult
 from tests.utils.bases.commands import TestProjectBase
 from tests.utils.cmdline import proc
@@ -79,6 +81,22 @@ class CheckSpider(scrapy.Spider):
         """
         self._test_contract(proj_path, contracts, parse_def, use_reactor=False)
 
+    @pytest.mark.parametrize("use_reactor", [True, False])
+    def test_check_crawl_error(self, proj_path: Path, use_reactor: bool) -> None:
+        self._write_contract(proj_path, "@returns requests 0", "pass")
+        self._append_settings(
+            proj_path / self.project_name,
+            "\nITEM_PIPELINES = {'nonexistent.module.Pipeline': 300}\n",
+        )
+        args = ["check"]
+        if not use_reactor:
+            args += ["-s", "TWISTED_REACTOR_ENABLED=False"]
+        ret, _, err = proc(*args, cwd=proj_path)
+        assert f"[{self.spider_name}] crawl" in err
+        assert "ModuleNotFoundError" in err
+        assert "FAILED (errors=1)" in err
+        assert ret == 1
+
     def test_check_returns_items_contract(self, proj_path: Path) -> None:
         contracts = """
         @returns items 1