refactor: put pth creation with the rest of the patching

Author: nedbat

coverage/files.py

@@ -11,10 +11,8 @@
 import os.path
 import posixpath
 import re
-import site
 import sys
 from collections.abc import Iterable
-from pathlib import Path
 from typing import Callable
 
 from coverage import env
@@ -216,19 +214,6 @@ def prep_patterns(patterns: Iterable[str]) -> list[str]:
     return prepped
 
 
-def create_pth_file() -> Path | None:
-    """Create .pth file for measuring subprocesses."""
-    for pth_dir in site.getsitepackages():  # pragma: part covered
-        pth_file = Path(pth_dir) / f"subcover_{os.getpid()}.pth"
-        try:
-            pth_file.write_text("import coverage; coverage.process_startup()\n", encoding="utf-8")
-        except OSError:  # pragma: cant happen
-            continue
-        else:
-            return pth_file
-    return None  # pragma: cant happen
-
-
 class TreeMatcher:
     """A matcher for files in a tree.
 

coverage/patch.py

@@ -7,11 +7,12 @@
 
 import atexit
 import os
+import site
+from pathlib import Path
 from typing import TYPE_CHECKING, Any, Callable, NoReturn
 
 from coverage import env
 from coverage.exceptions import ConfigError, CoverageException
-from coverage.files import create_pth_file
 
 if TYPE_CHECKING:
     from coverage import Coverage
@@ -87,3 +88,16 @@ def coverage_execv_patch(*args: Any, **kwargs: Any) -> Any:
 
         else:
             raise ConfigError(f"Unknown patch {patch!r}")
+
+
+def create_pth_file() -> Path | None:
+    """Create .pth file for measuring subprocesses."""
+    for pth_dir in site.getsitepackages():  # pragma: part covered
+        pth_file = Path(pth_dir) / f"subcover_{os.getpid()}.pth"
+        try:
+            pth_file.write_text("import coverage; coverage.process_startup()\n", encoding="utf-8")
+        except OSError:  # pragma: cant happen
+            continue
+        else:
+            return pth_file
+    return None  # pragma: cant happen

tests/conftest.py

@@ -17,7 +17,9 @@
 
 import pytest
 
-from coverage.files import set_relative_directory, create_pth_file
+from coverage.files import set_relative_directory
+from coverage.patch import create_pth_file
+
 
 # Pytest will rewrite assertions in test modules, but not elsewhere.
 # This tells pytest to also rewrite assertions in these files: