Add looponfailrootsignore option

changelog/633.feature.rst

@@ -0,0 +1 @@
+Add ``looponfailrootsignore`` to ignore generated files when using ``--looponfail``.

docs/index.rst

@@ -35,6 +35,9 @@ Features
   pytest waits until a file in your project changes and then re-runs
   the previously failing tests.  This is repeated until all tests pass
   after which again a full run is performed (DEPRECATED).
+  The ``looponfailroots`` configuration value can limit watched directories,
+  and ``looponfailrootsignore`` can ignore generated files using glob-style
+  path patterns.
 
 * :ref:`Multi-Platform` coverage: you can specify different Python interpreters
   or different platforms and run tests in parallel on all of them.

src/xdist/looponfail.py

@@ -35,6 +35,13 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         help="Run tests in subprocess: wait for files to be modified, then "
         "re-run failing test set until all pass.",
     )
+    group.addoption(
+        "--looponfailrootsignore",
+        action="append",
+        default=[],
+        metavar="GLOB",
+        help="Ignore glob-style paths when watching for --looponfail changes.",
+    )
 
 
 @pytest.hookimpl
@@ -54,7 +61,9 @@ def looponfail_main(config: pytest.Config) -> None:
     if not config_roots:
         config_roots = [Path.cwd()]
     rootdirs = [Path(root) for root in config_roots]
-    statrecorder = StatRecorder(rootdirs)
+    ignores = list(config.getoption("looponfailrootsignore", []))
+    ignores += config.getini("looponfailrootsignore")
+    statrecorder = StatRecorder(rootdirs, ignores=ignores)
     try:
         while 1:
             remotecontrol.loop_once()
@@ -248,16 +257,37 @@ def main(self) -> None:
 
 
 class StatRecorder:
-    def __init__(self, rootdirlist: Sequence[Path]) -> None:
+    def __init__(
+        self, rootdirlist: Sequence[Path], ignores: Sequence[str] = ()
+    ) -> None:
         self.rootdirlist = rootdirlist
+        self.ignore_patterns = tuple(ignores)
         self.statcache: dict[Path, os.stat_result] = {}
         self.check()  # snapshot state
 
     def fil(self, p: Path) -> bool:
-        return p.is_file() and not p.name.startswith(".") and p.suffix != ".pyc"
+        return (
+            p.is_file()
+            and not p.name.startswith(".")
+            and p.suffix != ".pyc"
+            and not self.is_ignored(p)
+        )
 
     def rec(self, p: Path) -> bool:
-        return not p.name.startswith(".") and p.exists()
+        return not p.name.startswith(".") and p.exists() and not self.is_ignored(p)
+
+    def is_ignored(self, p: Path) -> bool:
+        for pattern in self.ignore_patterns:
+            if Path(p.name).match(pattern) or p.match(pattern):
+                return True
+            for rootdir in self.rootdirlist:
+                try:
+                    relpath = p.relative_to(rootdir)
+                except ValueError:
+                    continue
+                if relpath.match(pattern):
+                    return True
+        return False
 
     def waitonchange(self, checkinterval: float = 1.0) -> None:
         while 1:

src/xdist/plugin.py

@@ -93,7 +93,10 @@ def _auto_num_workers_psutil(config: pytest.Config) -> int | None:
 
 def _auto_num_workers_os_sched_getaffinity(config: pytest.Config) -> int | None:
     try:
-        from os import sched_getaffinity
+        if TYPE_CHECKING:
+            sched_getaffinity: Callable[[int], set[int]]
+        else:
+            from os import sched_getaffinity
 
         return len(sched_getaffinity(0))
     except ImportError:
@@ -319,6 +322,11 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         type="paths",
         help="directories to check for changes. Default: current directory.",
     )
+    parser.addini(
+        "looponfailrootsignore",
+        type="args",
+        help="glob-style paths to ignore when checking for looponfail changes.",
+    )
 
 
 # -------------------------------------------------------------------------
@@ -362,9 +370,15 @@ def pytest_configure(config: pytest.Config) -> None:
             tr.showfspath = False
 
     # Deprecation warnings for deprecated command-line/configuration options.
-    if config.getoption("looponfail", None) or config.getini("looponfailroots"):
+    if (
+        config.getoption("looponfail", None)
+        or config.getini("looponfailroots")
+        or config.getoption("looponfailrootsignore", None)
+        or config.getini("looponfailrootsignore")
+    ):
         warning = DeprecationWarning(
-            "The --looponfail command line argument and looponfailroots config variable are deprecated.\n"
+            "The --looponfail command line argument and looponfailroots/looponfailrootsignore "
+            "config variables are deprecated.\n"
             "The loop-on-fail feature will be removed in pytest-xdist 4.0."
         )
         config.issue_config_time_warning(warning, 2)

testing/test_looponfail.py

@@ -9,6 +9,7 @@
 
 import pytest
 
+from xdist.looponfail import looponfail_main
 from xdist.looponfail import RemoteControl
 from xdist.looponfail import StatRecorder
 
@@ -54,6 +55,37 @@ def test_filechange(self, tmp_path: Path) -> None:
         changed = sd.check()
         assert changed
 
+    def test_filechange_ignored(self, tmp_path: Path) -> None:
+        tmp = tmp_path
+        hello = tmp / "hello.py"
+        generated = tmp / "generated.sqlite"
+        hello.touch()
+        generated.touch()
+        sd = StatRecorder([tmp], ignores=["*.sqlite"])
+        assert not sd.check()
+
+        generated.write_text("generated")
+        assert not sd.check()
+
+        hello.write_text("world")
+        assert sd.check()
+
+    def test_dirchange_ignored(self, tmp_path: Path) -> None:
+        tmp = tmp_path
+        generated = tmp / "generated"
+        generated.mkdir()
+        generated.joinpath("data.yaml").touch()
+        hello = tmp / "hello.py"
+        hello.touch()
+        sd = StatRecorder([tmp], ignores=["generated"])
+        assert not sd.check()
+
+        generated.joinpath("data.yaml").write_text("generated")
+        assert not sd.check()
+
+        hello.write_text("world")
+        assert sd.check()
+
     def test_dirchange(self, tmp_path: Path) -> None:
         tmp = tmp_path
         tmp.joinpath("dir").mkdir()
@@ -222,6 +254,43 @@ def test_func():
         assert not failures
 
 
+def test_looponfail_passes_ignore_patterns(
+    pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    pytester.makeini(
+        """
+        [pytest]
+        looponfailrootsignore = *.sqlite
+        """
+    )
+    config = pytester.parseconfigure("--looponfailrootsignore=*.yaml")
+    ignore_patterns = []
+
+    class FakeRemoteControl:
+        failures: list[str] = []
+        wasfailing = False
+
+        def __init__(self, config: pytest.Config) -> None:
+            pass
+
+        def loop_once(self) -> None:
+            pass
+
+    class FakeStatRecorder:
+        def __init__(self, rootdirs: list[Path], ignores: list[str]) -> None:
+            ignore_patterns.extend(ignores)
+
+        def waitonchange(self, checkinterval: float = 1.0) -> None:
+            raise KeyboardInterrupt
+
+    monkeypatch.setattr("xdist.looponfail.RemoteControl", FakeRemoteControl)
+    monkeypatch.setattr("xdist.looponfail.StatRecorder", FakeStatRecorder)
+
+    looponfail_main(config)
+
+    assert ignore_patterns == ["*.yaml", "*.sqlite"]
+
+
 class TestLooponFailing:
     def test_looponfail_from_fail_to_ok(self, pytester: pytest.Pytester) -> None:
         modcol = pytester.getmodulecol(