Do not cover lines that were excluded in the coveragerc config file (GH-3682)

Closes #3680.

Cython/Coverage.py

@@ -57,10 +57,19 @@ class Plugin(CoveragePlugin):
     _c_files_map = None
     # map from parsed C files to their content
     _parsed_c_files = None
+    # map from traced files to lines that are excluded from coverage
+    _excluded_lines_map = None
+    # list of regex patterns for lines to exclude
+    _excluded_line_patterns = ()
 
     def sys_info(self):
         return [('Cython version', __version__)]
 
+    def configure(self, config):
+        # Entry point for coverage "configurer".
+        # Read the regular expressions from the coverage config that match lines to be excluded from coverage.
+        self._excluded_line_patterns = config.get_option("report:exclude_lines")
+
     def file_tracer(self, filename):
         """
         Try to find a C source file for a file path found by the tracer.
@@ -108,7 +117,13 @@ class Plugin(CoveragePlugin):
             rel_file_path, code = self._read_source_lines(c_file, filename)
             if code is None:
                 return None  # no source found
-        return CythonModuleReporter(c_file, filename, rel_file_path, code)
+        return CythonModuleReporter(
+            c_file,
+            filename,
+            rel_file_path,
+            code,
+            self._excluded_lines_map.get(rel_file_path, frozenset())
+        )
 
     def _find_source_files(self, filename):
         basename, ext = os.path.splitext(filename)
@@ -218,10 +233,16 @@ class Plugin(CoveragePlugin):
             r'(?:struct|union|enum|class)'
             r'(\s+[^:]+|)\s*:'
         ).match
+        if self._excluded_line_patterns:
+            line_is_excluded = re.compile("|".join(["(?:%s)" % regex for regex in self._excluded_line_patterns])).search
+        else:
+            line_is_excluded = lambda line: False
 
         code_lines = defaultdict(dict)
         executable_lines = defaultdict(set)
         current_filename = None
+        if self._excluded_lines_map is None:
+            self._excluded_lines_map = defaultdict(set)
 
         with open(c_file) as lines:
             lines = iter(lines)
@@ -242,6 +263,9 @@ class Plugin(CoveragePlugin):
                         code_line = match.group(1).rstrip()
                         if not_executable(code_line):
                             break
+                        if line_is_excluded(code_line):
+                            self._excluded_lines_map[filename].add(lineno)
+                            break
                         code_lines[filename][lineno] = code_line
                         break
                     elif match_comment_end(comment_line):
@@ -298,11 +322,12 @@ class CythonModuleReporter(FileReporter):
     """
     Provide detailed trace information for one source file to coverage.py.
     """
-    def __init__(self, c_file, source_file, rel_file_path, code):
+    def __init__(self, c_file, source_file, rel_file_path, code, excluded_lines):
         super(CythonModuleReporter, self).__init__(source_file)
         self.name = rel_file_path
         self.c_file = c_file
         self._code = code
+        self._excluded_lines = excluded_lines
 
     def lines(self):
         """
@@ -310,6 +335,12 @@ class CythonModuleReporter(FileReporter):
         """
         return set(self._code)
 
+    def excluded_lines(self):
+        """
+        Return set of line numbers that are excluded from coverage.
+        """
+        return self._excluded_lines
+
     def _iter_source_tokens(self):
         current_line = 1
         for line_no, code_line in sorted(self._code.items()):
@@ -345,4 +376,6 @@ class CythonModuleReporter(FileReporter):
 
 
 def coverage_init(reg, options):
-    reg.add_file_tracer(Plugin())
+    plugin = Plugin()
+    reg.add_configurer(plugin)
+    reg.add_file_tracer(plugin)

tests/run/coverage_cmd.srctree

@@ -40,6 +40,13 @@ def func2(a):
     return a * 2        # 11
 
 
+def func3(a):
+    x = 1               # 15
+    a *= 2              #     # pragma: no cover
+    a += x              #
+    return a * 42       # 18  # pragma: no cover
+
+
 ######## pkg/coverage_test_pyx.pyx ########
 # cython: linetrace=True
 # distutils: define_macros=CYTHON_TRACE=1
@@ -54,6 +61,13 @@ def func2(int a):
     return a * 2        # 11
 
 
+def func3(int a):
+    cdef int x = 1      # 15
+    a *= 2              #     # pragma: no cover
+    a += x              #
+    return a * 42       # 18  # pragma: no cover
+
+
 ######## coverage_test_include_pyx.pyx ########
 # cython: linetrace=True
 # distutils: define_macros=CYTHON_TRACE=1
@@ -152,8 +166,9 @@ def run_report():
                 missing.append(int(start))
         files[os.path.basename(name)] = (statements, missed, covered, missing)
 
-    assert  7 not in files['coverage_test_pyx.pyx'][-1], files['coverage_test_pyx.pyx']
-    assert 12 not in files['coverage_test_pyx.pyx'][-1], files['coverage_test_pyx.pyx']
+    report = files['coverage_test_pyx.pyx']
+    assert  7 not in report[-1], report
+    assert 12 not in report[-1], report
 
 
 def run_xml_report():
@@ -170,35 +185,74 @@ def run_xml_report():
             for line in module.findall('lines/line')
         )
 
-    assert files['pkg/coverage_test_pyx.pyx'][5] > 0, files['pkg/coverage_test_pyx.pyx']
-    assert files['pkg/coverage_test_pyx.pyx'][6] > 0, files['pkg/coverage_test_pyx.pyx']
-    assert files['pkg/coverage_test_pyx.pyx'][7] > 0, files['pkg/coverage_test_pyx.pyx']
+    report = files['pkg/coverage_test_pyx.pyx']
+    assert report[5] > 0, report
+    assert report[6] > 0, report
+    assert report[7] > 0, report
+
+
+def run_json_report():
+    import coverage
+    if coverage.version_info < (5, 0):
+        # JSON output comes in coverage 5.0
+        return
+
+    stdout = run_coverage_command('json', '-o', '-')
+
+    import json
+    files = json.loads(stdout.decode("ascii"))['files']
+
+    for filename in [
+        'pkg/coverage_test_py.py',
+        'pkg/coverage_test_pyx.pyx',
+    ]:
+        report = files[filename]
+        summary = report['summary']
+        assert summary['missing_lines'] == 2, summary
+        assert summary['excluded_lines'] == 2, summary
+        assert report['missing_lines'] == [15, 17], report
+        assert report['excluded_lines'] == [16, 18], report
+
+        assert not frozenset(
+            report['missing_lines'] + report['excluded_lines']
+        ).intersection(report['executed_lines'])
 
 
 def run_html_report():
+    from collections import defaultdict
+
     stdout = run_coverage_command('html', '-d', 'html')
     _parse_lines = re.compile(
         r'<p[^>]* id=["\'][^0-9"\']*(?P<id>[0-9]+)[^0-9"\']*["\'][^>]*'
-        r' class=["\'][^"\']*(?P<run>mis|run)[^"\']*["\']').findall
+        r' class=["\'][^"\']*(?P<run>mis|run|exc)[^"\']*["\']').findall
 
     files = {}
     for file_path in iglob('html/*.html'):
         with open(file_path) as f:
             page = f.read()
-        executed = set()
-        missing = set()
-        for line, has_run in _parse_lines(page):
-            (executed if has_run == 'run' else missing).add(int(line))
-        files[file_path] = (executed, missing)
+        report = defaultdict(set)
+        for line, state in _parse_lines(page):
+            report[state].add(int(line))
+        files[file_path] = report
 
-    executed, missing = [data for path, data in files.items() if 'coverage_test_pyx' in path][0]
-    assert executed
-    assert 5 in executed, executed
-    assert 6 in executed, executed
-    assert 7 in executed, executed
+    for filename, report in files.items():
+        if "coverage_test_pyx" not in filename:
+            continue
+        executed = report["run"]
+        missing = report["mis"]
+        excluded = report["exc"]
+        assert executed
+        assert 5 in executed, executed
+        assert 6 in executed, executed
+        assert 7 in executed, executed
+        assert 15 in missing, missing
+        assert 16 in excluded, excluded
+        assert 17 in missing, missing
+        assert 18 in excluded, excluded
 
 
 if __name__ == '__main__':
     run_report()
     run_xml_report()
+    run_json_report()
     run_html_report()