fix: don't overwrite a .gitignore in the html output directory. #1244

Author: nedbat

CHANGES.rst

@@ -25,6 +25,9 @@ Unreleased
 - Fix: A colon in a decorator expression would cause an exclusion to end too
   early, preventing the exclusion of the decorated function. This is now fixed.
 
+- Fix: The HTML report now will not overwrite a .gitignore file that already
+  exists in the HTML output directory (follow-on for `issue 1244`_).
+
 
 .. _changes_612:
 

coverage/html.py

@@ -226,8 +226,10 @@ def make_local_static_report_files(self):
 
         # .gitignore can't be copied from the source tree because it would
         # prevent the static files from being checked in.
-        with open(os.path.join(self.directory, ".gitignore"), "w") as fgi:
-            fgi.write("# Created by coverage.py\n*\n")
+        gitigore_path = os.path.join(self.directory, ".gitignore")
+        if not os.path.exists(gitigore_path):
+            with open(gitigore_path, "w") as fgi:
+                fgi.write("# Created by coverage.py\n*\n")
 
         # The user may have extra CSS they want copied.
         if self.extra_css:

tests/test_html.py

@@ -284,6 +284,13 @@ def test_status_format_change(self):
         assert "htmlcov/helper2_py.html" in self.files_written
         assert "htmlcov/main_file_py.html" in self.files_written
 
+    def test_dont_overwrite_gitignore(self):
+        self.create_initial_files()
+        self.make_file("htmlcov/.gitignore", "# ignore nothing")
+        self.run_coverage()
+        with open("htmlcov/.gitignore") as fgi:
+            assert fgi.read() == "# ignore nothing"
+
 
 class HtmlTitleTest(HtmlTestHelpers, CoverageTest):
     """Tests of the HTML title support."""