fix: don't combine journal files. #1605

CHANGES.rst

@@ -24,6 +24,11 @@ Unreleased
   ``[report] exclude_also`` settings (`issue 1684`_).  This is now fixed,
   thanks `Jacqueline Lee <pull 1685_>`_.
 
+- Sometimes SQLite will create journal files alongside the coverage.py database
+  files.  These are ephemeral, but could be mistakenly included when combining
+  data files.  Now they are always ignored, fixing `issue 1605`_.
+
+.. _issue 1605: https://github.com/nedbat/coveragepy/pull/1605
 .. _issue 1684: https://github.com/nedbat/coveragepy/issues/1684
 .. _pull 1685: https://github.com/nedbat/coveragepy/pull/1685
 

coverage/data.py

@@ -83,6 +83,11 @@ def combinable_files(data_file: str, data_paths: Optional[Iterable[str]] = None)
             files_to_combine.extend(glob.glob(pattern))
         else:
             raise NoDataError(f"Couldn't combine from non-existent path '{p}'")
+
+    # SQLite might have made journal files alongside our database files.
+    # We never want to combine those.
+    files_to_combine = [fnm for fnm in files_to_combine if not fnm.endswith("-journal")]
+
     return files_to_combine
 
 

tests/test_data.py

@@ -887,6 +887,9 @@ def test_combining_from_files(self) -> None:
         covdata1.add_lines(LINES_1)
         covdata1.write()
 
+        # Journal files should never be included in the combining.
+        self.make_file("cov1/.coverage.1-journal", "xyzzy")
+
         os.makedirs('cov2')
         covdata2 = DebugCoverageData('cov2/.coverage.2')
         covdata2.add_lines(LINES_2)