1 files changed, 63 insertions, 0 deletions
diff --git a/config/check_source_count.py b/config/check_source_count.py
new file mode 100755
index 0000000000..a0a3f2c6d4
--- /dev/null
+++ b/config/check_source_count.py
@@ -0,0 +1,63 @@
+#!/usr/bin/env python
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# Usage: check_source_count.py SEARCH_TERM COUNT ERROR_LOCATION REPLACEMENT [FILES...]
+#   Checks that FILES contains exactly COUNT matches of SEARCH_TERM. If it does
+#   not, an error message is printed, quoting ERROR_LOCATION, which should
+#   probably be the filename and line number of the erroneous call to
+#   check_source_count.py.
+import re
+import sys
+
+search_string = sys.argv[1]
+expected_count = int(sys.argv[2])
+error_location = sys.argv[3]
+replacement = sys.argv[4]
+files = sys.argv[5:]
+
+details = {}
+
+count = 0
+for f in files:
+    text = file(f).read()
+    match = re.findall(search_string, text)
+    if match:
+        num = len(match)
+        count += num
+        details[f] = num
+
+if count == expected_count:
+    print(
+        "TEST-PASS | check_source_count.py {0} | {1}".format(
+            search_string, expected_count
+        )
+    )
+
+else:
+    print(
+        "TEST-UNEXPECTED-FAIL | check_source_count.py {0} | ".format(search_string),
+        end="",
+    )
+    if count < expected_count:
+        print(
+            "There are fewer occurrences of /{0}/ than expected. "
+            "This may mean that you have removed some, but forgotten to "
+            "account for it {1}.".format(search_string, error_location)
+        )
+    else:
+        print(
+            "There are more occurrences of /{0}/ than expected. We're trying "
+            "to prevent an increase in the number of {1}'s, using {2} if "
+            "possible. If it is unavoidable, you should update the expected "
+            "count {3}.".format(
+                search_string, search_string, replacement, error_location
+            )
+        )
+
+    print("Expected: {0}; found: {1}".format(expected_count, count))
+    for k in sorted(details):
+        print("Found {0} occurences in {1}".format(details[k], k))
+    sys.exit(-1)