The [paths] setting is ordered. #649

CHANGES.rst

@@ -33,12 +33,17 @@ Unreleased
   fixes `issue 745`_ (about not being able to run unittest tests that spawn
   subprocesses), and `issue 838`_, which described the problem directly.
 
+- The ``[paths]`` configuration section is now ordered. If you specify more
+  than one list of patterns, the first one that matches will be used.  Fixes
+  `issue 649`_.
+
 - The :func:`.coverage.numbits.register_sqlite_functions` function now also
   registers `numbits_to_nums` for use in SQLite queries.  Thanks, Simon
   Willison.
 
 - Python 3.9a1 is supported.
 
+.. _issue 649: https://github.com/nedbat/coveragepy/issues/649
 .. _issue 745: https://github.com/nedbat/coveragepy/issues/745
 .. _issue 838: https://github.com/nedbat/coveragepy/issues/838
 

coverage/config.py

@@ -226,7 +226,7 @@ def __init__(self):
         self.json_show_contexts = False
 
         # Defaults for [paths]
-        self.paths = {}
+        self.paths = collections.OrderedDict()
 
         # Options for plugins
         self.plugin_options = {}
@@ -536,6 +536,9 @@ def read_coverage_config(config_file, **kwargs):
     config.data_file = os.path.expanduser(config.data_file)
     config.html_dir = os.path.expanduser(config.html_dir)
     config.xml_output = os.path.expanduser(config.xml_output)
-    config.paths = {k: [os.path.expanduser(f) for f in v] for k, v in config.paths.items()}
+    config.paths = collections.OrderedDict(
+        (k, [os.path.expanduser(f) for f in v])
+        for k, v in config.paths.items()
+    )
 
     return config

doc/config.rst

@@ -238,6 +238,9 @@ In this example, data collected for "/jenkins/build/1234/src/module.py" will be
 combined with data for "c:\myproj\src\module.py", and will be reported against
 the source file found at "src/module.py".
 
+If you specify more than one list of paths, they will be considered in order.
+The first list that has a match will be used.
+
 See :ref:`cmd_combining` for more information.
 
 

tests/test_api.py

@@ -425,6 +425,49 @@ def test_combining_with_a_used_coverage(self):
         cov.combine()
         self.check_code1_code2(cov)
 
+    def test_ordered_combine(self):
+        # https://github.com/nedbat/coveragepy/issues/649
+        # The order of the [paths] setting matters
+        def make_data_file():
+            data = coverage.CoverageData(".coverage.1")
+            data.add_lines({os.path.abspath('ci/girder/g1.py'): dict.fromkeys(range(10))})
+            data.add_lines({os.path.abspath('ci/girder/plugins/p1.py'): dict.fromkeys(range(10))})
+            data.write()
+
+        def get_combined_filenames():
+            cov = coverage.Coverage()
+            cov.combine()
+            cov.save()
+            data = cov.get_data()
+            filenames = {os.path.relpath(f).replace("\\", "/") for f in data.measured_files()}
+            return filenames
+
+        # Case 1: get the order right.
+        make_data_file()
+        self.make_file(".coveragerc", """\
+            [paths]
+            plugins =
+                plugins/
+                ci/girder/plugins/
+            girder =
+                girder/
+                ci/girder/
+            """)
+        assert get_combined_filenames() == {'girder/g1.py', 'plugins/p1.py'}
+
+        # Case 2: get the order wrong.
+        make_data_file()
+        self.make_file(".coveragerc", """\
+            [paths]
+            girder =
+                girder/
+                ci/girder/
+            plugins =
+                plugins/
+                ci/girder/plugins/
+            """)
+        assert get_combined_filenames() == {'girder/g1.py', 'girder/plugins/p1.py'}
+
     def test_warnings(self):
         self.make_file("hello.py", """\
             import sys, os