fix: isolate user code from coverage.py internal code flags. #1524

CHANGES.rst

@@ -20,7 +20,11 @@ development at the same time, such as 4.5.x and 5.0.
 Unreleased
 ----------
 
-Nothing yet.
+- Fix: On Python 3.7, a file with type annotations but no ``from __future__
+  import annotations`` would be missing statements in the coverage report. This
+  is now fixed, closing `issue 1524`_.
+
+.. _issue 1524: https://github.com/nedbat/coveragepy/issues/1524
 
 
 .. _changes_7-0-4:

coverage/execfile.py

@@ -275,7 +275,7 @@ def make_code_from_py(filename):
     except (OSError, NoSource) as exc:
         raise NoSource(f"No file to run: '{filename}'") from exc
 
-    return compile(source, filename, "exec")
+    return compile(source, filename, "exec", dont_inherit=True)
 
 
 def make_code_from_pyc(filename):

coverage/parser.py

@@ -385,7 +385,7 @@ def __init__(
         else:
             assert filename is not None
             try:
-                self.code = compile(text, filename, "exec")
+                self.code = compile(text, filename, "exec", dont_inherit=True)
             except SyntaxError as synerr:
                 raise NotPython(
                     "Couldn't parse '%s' as Python source: '%s' at line %d" % (

lab/genpy.py

@@ -231,7 +231,7 @@ def show_a_bunch():
         source = PythonSpinner.generate_python(maker.make_body("def"))
         try:
             print("-"*80, "\n", source, sep="")
-            compile(source, "<string>", "exec")
+            compile(source, "<string>", "exec", dont_inherit=True)
         except Exception as ex:
             print(f"Oops: {ex}\n{source}")
         if len(source) > len(longest):

lab/parser.py

@@ -177,7 +177,7 @@ def all_code_objects(code):
 def disassemble(pyparser):
     """Disassemble code, for ad-hoc experimenting."""
 
-    code = compile(pyparser.text, "", "exec")
+    code = compile(pyparser.text, "", "exec", dont_inherit=True)
     for code_obj in all_code_objects(code):
         if pyparser.text:
             srclines = pyparser.text.splitlines()

lab/show_pyc.py

@@ -48,7 +48,7 @@ def show_py_file(fname):
     show_py_text(text, fname=fname)
 
 def show_py_text(text, fname="<string>"):
-    code = compile(text, fname, "exec")
+    code = compile(text, fname, "exec", dont_inherit=True)
     show_code(code)
 
 CO_FLAGS = [

setup.py

@@ -59,7 +59,7 @@ def better_set_verbosity(v):
     # Keep pylint happy.
     __version__ = __url__ = version_info = ""
     # Execute the code in version.py.
-    exec(compile(version_file.read(), cov_ver_py, 'exec'))
+    exec(compile(version_file.read(), cov_ver_py, 'exec', dont_inherit=True))
 
 with open("README.rst") as readme:
     readme_text = readme.read()

tests/test_cmdline.py

@@ -142,7 +142,7 @@ def cmd_executes(
         code = textwrap.dedent(code)
         expected = self.model_object()
         globs = {n: getattr(expected, n) for n in self.MOCK_GLOBALS}
-        code_obj = compile(code, "<code>", "exec")
+        code_obj = compile(code, "<code>", "exec", dont_inherit=True)
         eval(code_obj, globs, {})                           # pylint: disable=eval-used
 
         # Many of our functions take a lot of arguments, and cmdline.py

tests/test_summary.py

@@ -849,6 +849,22 @@ def missing(x, y):
         assert self.get_report(cov, output_format="total", precision=2) == "78.57\n"
         assert self.get_report(cov, output_format="total", precision=4) == "78.5714\n"
 
+    def test_bug_1524(self) -> None:
+        self.make_file("bug1524.py", """\
+            class Mine:
+                @property
+                def thing(self) -> int:
+                    return 17
+
+            print(Mine().thing)
+            """)
+        cov = coverage.Coverage()
+        self.start_import_stop(cov, "bug1524")
+        assert self.stdout() == "17\n"
+        report = self.get_report(cov)
+        report_lines = report.splitlines()
+        assert report_lines[2] == "bug1524.py 5 0 100%"
+
 
 class ReportingReturnValueTest(CoverageTest):
     """Tests of reporting functions returning values."""