fix coverage reporting for gcc 8 and code that uses templates

cpp_coveralls/coverage.py

@@ -260,7 +260,11 @@ def parse_gcov_file(args, fobj, filename):
         cov_num = report_fields[0].strip()
         line_num = int(line_num)
         text = report_fields[2]
-        if line_num == 0:
+
+        # skip gcov meta data and
+        # repeated lines for instances(templated code), because the 1st occurence reports the total count, we can
+        # ignore the instance specializations
+        if line_num == 0 or line_num <= len(coverage):
             continue
         if re.search(r'\bLCOV_EXCL_START\b', text):
             if ignoring:

cpp_coveralls/parse_gcov_test.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
+#
+
+import io
+import unittest
+
+from . import coverage
+
+
+class ParseGcovTest(unittest.TestCase):
+    # test template example from the documentation (https://gcc.gnu.org/onlinedocs/gcc/Invoking-Gcov.html#Invoking-Gcov)
+    def test_templated_coverage(self):
+        args = coverage.create_args("")
+        f = io.BytesIO(b"""
+        -:    0:Source:tmp.cpp
+        -:    0:Working directory:/home/gcc/testcase
+        -:    0:Graph:tmp.gcno
+        -:    0:Data:tmp.gcda
+        -:    0:Runs:1
+        -:    0:Programs:1
+        -:    1:#include <stdio.h>
+        -:    2:
+        -:    3:template<class T>
+        -:    4:class Foo
+        -:    5:{
+        -:    6:  public:
+       1*:    7:  Foo(): b (1000) {}
+------------------
+Foo<char>::Foo():
+    #####:    7:  Foo(): b (1000) {}
+------------------
+Foo<int>::Foo():
+        1:    7:  Foo(): b (1000) {}
+------------------
+        """)
+        parsed_lines = coverage.parse_gcov_file(args, f, "bar")
+        self.assertEqual(7, len(parsed_lines))
+        self.assertEqual(1, parsed_lines[6])