Abort collection errors from pytest_collection

changelog/15028.breaking.rst

@@ -0,0 +1 @@
+Collection errors now abort from the default :hook:`pytest_collection` hook rather than :hook:`pytest_runtestloop`. A plugin that replaces ``pytest_runtestloop`` still sees the abort. A plugin that replaces ``pytest_collection`` entirely has to perform the ``testsfailed`` check itself if it wants the same guard.

src/_pytest/hookspec.py

@@ -251,6 +251,8 @@ def pytest_collection(session: Session) -> object | None:
     3. Set ``session.items`` to the list of collected items
     4. ``pytest_collection_finish(session)``
     5. Set ``session.testscollected`` to the number of collected items
+    6. Abort with :class:`~pytest.Interrupted` if collection reported errors
+       (unless ``--continue-on-collection-errors`` is set)
 
     You can implement this hook to only perform some action before collection,
     for example the terminal plugin uses it to start displaying the collection
@@ -595,8 +597,8 @@ def pytest_runtestloop(session: Session) -> object | None:
     """Perform the main runtest loop (after collection finished).
 
     The default hook implementation performs the runtest protocol for all items
-    collected in the session (``session.items``), unless the collection failed
-    or the ``collectonly`` pytest option is set.
+    collected in the session (``session.items``), unless the
+    ``collectonly`` pytest option is set.
 
     If at any point :py:func:`pytest.exit` is called, the loop is
     terminated immediately.

src/_pytest/main.py

@@ -392,14 +392,13 @@ def _main(config: Config, session: Session) -> int | ExitCode | None:
 
 def pytest_collection(session: Session) -> None:
     session.perform_collect()
-
-
-def pytest_runtestloop(session: Session) -> bool:
     if session.testsfailed and not session.config.option.continue_on_collection_errors:
         raise session.Interrupted(
             f"{session.testsfailed} error{'s' if session.testsfailed != 1 else ''} during collection"
         )
 
+
+def pytest_runtestloop(session: Session) -> bool:
     if session.config.option.collectonly:
         return True
 

testing/test_collection.py

@@ -1132,6 +1132,23 @@ def test_continue_on_collection_errors_maxfail(pytester: Pytester) -> None:
     res.stdout.fnmatch_lines(["collected 2 items / 2 errors", "*1 failed, 2 errors*"])
 
 
+def test_collection_error_aborts_before_custom_runtestloop(pytester: Pytester) -> None:
+    pytester.makeconftest(
+        """
+        def pytest_runtestloop(session):
+            raise AssertionError("runtestloop must not run after a collection error")
+        """
+    )
+    pytester.makepyfile(
+        """
+        import nosuchmodule
+        """
+    )
+    res = pytester.runpytest()
+    assert res.ret == ExitCode.INTERRUPTED
+    res.stdout.fnmatch_lines(["*! Interrupted: 1 error during collection !*"])
+
+
 def test_fixture_scope_sibling_conftests(pytester: Pytester) -> None:
     """Regression test case for https://github.com/pytest-dev/pytest/issues/2836"""
     foo_path = pytester.mkdir("foo")