fix: lcov report indexeerror for some Jinja2 files. #1553

coverage/lcovreport.py

@@ -74,6 +74,8 @@ def get_lcov(self, fr: FileReporter, analysis: Analysis, outfile: IO[str]) -> No
             # characters of the encoding ("==") are removed from the hash to
             # allow genhtml to run on the resulting lcov file.
             if source_lines:
+                if covered-1 >= len(source_lines):
+                    break
                 line = source_lines[covered-1]
             else:
                 line = ""

tests/test_report_common.py

@@ -156,3 +156,87 @@ def test_map_paths_during_lcov_report(self) -> None:
         cov.lcov_report()
         contains("coverage.lcov", os_sep("src/program.py"))
         doesnt_contain("coverage.lcov", os_sep("ver1/program.py"), os_sep("ver2/program.py"))
+
+
+class ReportWithJinjaTest(CoverageTest):
+    """Tests of Jinja-like behavior.
+
+    Jinja2 compiles a template (template.j2) into Python code, and then runs the
+    Python code to render the template.  But during rendering, it uses "template.j2"
+    as the file name.  During reporting, we will try to parse template.j2 as
+    Python code.
+
+    See https://github.com/nedbat/coveragepy/issues/1553 for more detail.
+
+    """
+
+    def make_files(self) -> None:
+        # A Jinja2 file that is syntactically acceptable Python (though it wont run).
+        self.make_file("good.j2", """\
+            {{ data }}
+            line2
+            line3
+            """)
+        # A Jinja2 file that is a Python syntax error.
+        self.make_file("bad.j2", """\
+            This is data: {{ data }}.
+            line 2
+            line 3
+            """)
+        self.make_data_file(
+            lines={
+                abs_file("good.j2"): [1, 3, 5, 7, 9],
+                abs_file("bad.j2"): [1, 3, 5, 7, 9],
+            }
+        )
+
+    def test_report(self) -> None:
+        self.make_files()
+        cov = coverage.Coverage()
+        cov.load()
+        cov.report(show_missing=True)
+        expected = textwrap.dedent("""\
+            Name      Stmts   Miss  Cover   Missing
+            ---------------------------------------
+            good.j2       3      1    67%   2
+            ---------------------------------------
+            TOTAL         3      1    67%
+            """)
+        assert expected == self.stdout()
+
+    def test_html(self) -> None:
+        self.make_files()
+        cov = coverage.Coverage()
+        cov.load()
+        cov.html_report()
+        contains("htmlcov/index.html", "good.j2")
+        doesnt_contain("htmlcov/index.html", "bad.j2")
+
+    def test_xml(self) -> None:
+        self.make_files()
+        cov = coverage.Coverage()
+        cov.load()
+        cov.xml_report()
+        contains("coverage.xml", "good.j2")
+        doesnt_contain("coverage.xml", "bad.j2")
+
+    def test_json(self) -> None:
+        self.make_files()
+        cov = coverage.Coverage()
+        cov.load()
+        cov.json_report()
+        contains("coverage.json", "good.j2")
+        doesnt_contain("coverage.json", "bad.j2")
+
+    def test_lcov(self) -> None:
+        self.make_files()
+        cov = coverage.Coverage()
+        cov.load()
+        cov.lcov_report()
+        contains("coverage.lcov",
+            "SF:good.j2",
+            "DA:1,1,FHs1rDakj9p/NAzMCu3Kgw",
+            "DA:3,1,DGOyp8LEgI+3CcdFYw9uKQ",
+            "DA:2,0,5iUbzxp9w7peeTPjJbvmBQ",
+        )
+        doesnt_contain("coverage.lcov", "SF:bad.j2")