Fix a potential crash for accessors like "{0.missing}".

3 files changed, 4 insertions, 2 deletions

diff --git a/checkers/strings.py b/checkers/strings.py
index 4f4293a..9be6627 100644
--- a/checkers/strings.py
+++ b/checkers/strings.py
@@ -188,7 +188,7 @@ def get_access_path(key, parts):
             path.append(".{}".format(specifier))
         else:
             path.append("[{!r}]".format(specifier))
-    return key + "".join(path)
+    return str(key) + "".join(path)
 
 
 class StringFormatChecker(BaseChecker):
diff --git a/test/input/func_string_format_py27.py b/test/input/func_string_format_py27.py
index cd3071b..a492bb2 100644
--- a/test/input/func_string_format_py27.py
+++ b/test/input/func_string_format_py27.py
@@ -68,3 +68,4 @@ def pprint():
     print "{a}".format(a=Missing())

     print log("{}".format(2, "info"))

     print "{pid}".format(pid=os.getpid())

+    print "{0.missing}".format(2)

diff --git a/test/messages/func_string_format_py27.txt b/test/messages/func_string_format_py27.txt
index 632ff60..53edb8b 100644
--- a/test/messages/func_string_format_py27.txt
+++ b/test/messages/func_string_format_py27.txt
@@ -20,4 +20,5 @@ W: 61:pprint: Using invalid lookup key 400 in format specifier 'a.ids[3][400]'
 W: 62:pprint: Using invalid lookup key "'string'" in format specifier 'a.ids[3]["\'string\'"]'

 W: 66:pprint: Missing keyword argument 'b' for format string

 W: 66:pprint: Unused format argument 'a'

-W: 67:pprint: Using invalid lookup key 0 in format specifier 'a[0]'
\ No newline at end of file
+W: 67:pprint: Using invalid lookup key 0 in format specifier 'a[0]'

+W: 71:pprint: Missing format attribute 'missing' in format specifier '0.missing'
\ No newline at end of file