Improve specificity of warning text

hypothesis-python/src/hypothesis/configuration.py

@@ -9,6 +9,7 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import os
+import sys
 import warnings
 from pathlib import Path
 
@@ -45,7 +46,7 @@ def storage_directory(*names, intent_to_write=True):
 
 
 def check_sideeffect_during_initialization(
-    what: str, *fmt_args: object, extra: str = ""
+    what: str, *fmt_args: object, is_restart: bool = False
 ) -> None:
     """Called from locations that should not be executed during initialization, for example
     touching disk or materializing lazy/deferred strategies from plugins. If initialization
@@ -61,12 +62,25 @@ def check_sideeffect_during_initialization(
     if _first_postinit_what is not None:
         return
     elif _hypothesis_globals.in_initialization > 0:
+        msg = what.format(*fmt_args)
+        if is_restart:
+            when = "between importing hypothesis and loading the hypothesis plugin"
+        elif "_hypothesis_pytestplugin" in sys.modules or os.getenv(
+            "HYPOTHESIS_EXTEND_INITIALIZATION"
+        ):
+            when = "during pytest plugin or conftest initialization"
+        else:
+            when = "at import time"
         # Note: -Werror is insufficient under pytest, as doesn't take effect until
         # test session start.
-        msg = what.format(*fmt_args)
+        text = (
+            f"Slow code in plugin: avoid {msg} {when}!  Set PYTHONWARNINGS=error "
+            "to get a traceback and show which plugin is responsible."
+        )
+        if is_restart:
+            text += " Additionally, set HYPOTHESIS_EXTEND_INITIALIZATION=1 to pinpoint the exact location."
         warnings.warn(
-            f"Slow code in plugin: avoid {msg} at import time!  Set PYTHONWARNINGS=error "
-            "to get a traceback and show which plugin is responsible." + extra,
+            text,
             HypothesisSideeffectWarning,
             stacklevel=3,
         )
@@ -87,5 +101,5 @@ def notice_initialization_restarted(*, warn: bool = True) -> None:
             check_sideeffect_during_initialization(
                 what,
                 *fmt_args,
-                extra=" Additionally, set HYPOTHESIS_EXTEND_INITIALIZATION=1 to pinpoint the exact location.",
+                is_restart=True,
             )

hypothesis-python/tests/cover/test_sideeffect_warnings.py

@@ -54,6 +54,7 @@ def test_sideeffect_delayed_warning(monkeypatch, _extend_initialization):
     monkeypatch.setattr(_hypothesis_globals, IN_INITIALIZATION_ATTR, 0)
     fs.check_sideeffect_during_initialization(what)
     fs.check_sideeffect_during_initialization("ignored since not first")
-    with pytest.warns(HypothesisSideeffectWarning, match=what):
+    # The warning should identify itself as happening after import but before plugin load
+    with pytest.warns(HypothesisSideeffectWarning, match=what + ".*between import"):
         monkeypatch.setattr(_hypothesis_globals, IN_INITIALIZATION_ATTR, 1)
         fs.notice_initialization_restarted()

hypothesis-python/tests/pytest/test_sideeffect_warnings.py

@@ -50,6 +50,8 @@ def test_conftest_sideeffect_pinpoint_error(testdir, monkeypatch):
     script = testdir.makepyfile(TEST_SCRIPT)
     result = testdir.runpytest_subprocess(script)
     assert "HypothesisSideeffectWarning" in "\n".join(result.errlines)
+    # Plugin is always loaded before conftest, so "during pytest plugin initialization"
+    assert "during pytest" in "\n".join(result.errlines)
     assert SIDEEFFECT_STATEMENT in "\n".join(result.errlines)
 
 
@@ -62,4 +64,6 @@ def test_plugin_sideeffect_pinpoint_error(testdir, monkeypatch):
     script = testdir.makepyfile(TEST_SCRIPT)
     result = testdir.runpytest_subprocess(script, "-p", "sideeffect_plugin")
     assert "HypothesisSideeffectWarning" in "\n".join(result.errlines)
+    # Plugin order unknown, but certainly not at import time
+    assert "at import time" not in "\n".join(result.errlines)
     assert SIDEEFFECT_STATEMENT in "\n".join(result.errlines)