add tempfile soc idea

Author: peff

SoC-2014-Ideas.md

@@ -90,3 +90,18 @@ prompt shows publish-state.
 - Language: C, Shell
 - Difficulty: medium
 - Possible mentors: Ramkumar Ramachandra
+
+## Refactor tempfile handling
+
+When performing operations that fail, git typically writes to a
+temporary file and then atomically moves it into place. During failures,
+some of these temporary files may be left in place. This is convenient
+for forensics, but inconvenient when the files are very large
+(especially if the operation failed due to running out of disk space).
+Refactor the handling of temporary packs and object files so that they
+can optionally be cleaned up automatically. The implementation should be
+shared with other files that are cleaned automatically, like lockfiles.
+
+- Language: C
+- Difficulty: easy
+- Possible mentors: Jeff King