From: Junio C Hamano <gitster@pobox.com>
Date: Thu, 6 Nov 2014 18:51:35 +0000 (-0800)
Subject: Merge branch 'jk/cache-tree-protect-from-broken-libgit2'
X-Git-Tag: v2.2.0-rc1~6
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/e44da1bbb83f8dac4ea2ae7c806383af470edd38?ds=inline;hp=-c

Merge branch 'jk/cache-tree-protect-from-broken-libgit2'

The code to use cache-tree trusted the on-disk data too much
and fell into an infinite loop.

* jk/cache-tree-protect-from-broken-libgit2:
cache-tree: avoid infinite loop on zero-entry tree
---

e44da1bbb83f8dac4ea2ae7c806383af470edd38
diff --combined cache-tree.c
index 215202c42d,648e187491..32772b9564
--- a/cache-tree.c
+++ b/cache-tree.c
@@@ -1,5 -1,4 +1,5 @@@
  #include "cache.h"
 +#include "lockfile.h"
  #include "tree.h"
  #include "tree-walk.h"
  #include "cache-tree.h"
@@@ -247,12 -246,9 +247,12 @@@ static int update_one(struct cache_tre
  	struct strbuf buffer;
  	int missing_ok = flags & WRITE_TREE_MISSING_OK;
  	int dryrun = flags & WRITE_TREE_DRY_RUN;
 +	int repair = flags & WRITE_TREE_REPAIR;
  	int to_invalidate = 0;
  	int i;
  
 +	assert(!(dryrun && repair));
 +
  	*skip_count = 0;
  
  	if (0 <= it->entry_count && has_sha1_file(it->sha1))
@@@ -303,6 -299,8 +303,8 @@@
  				    flags);
  		if (subcnt < 0)
  			return subcnt;
+ 		if (!subcnt)
+ 			die("index cache-tree records empty sub-tree");
  		i += subcnt;
  		sub->count = subcnt; /* to be used in the next loop */
  		*skip_count += subskip;
@@@ -324,7 -322,6 +326,7 @@@
  		int pathlen, entlen;
  		const unsigned char *sha1;
  		unsigned mode;
 +		int expected_missing = 0;
  
  		path = ce->name;
  		pathlen = ce_namelen(ce);
@@@ -341,10 -338,8 +343,10 @@@
  			i += sub->count;
  			sha1 = sub->cache_tree->sha1;
  			mode = S_IFDIR;
 -			if (sub->cache_tree->entry_count < 0)
 +			if (sub->cache_tree->entry_count < 0) {
  				to_invalidate = 1;
 +				expected_missing = 1;
 +			}
  		}
  		else {
  			sha1 = ce->sha1;
@@@ -354,8 -349,6 +356,8 @@@
  		}
  		if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1)) {
  			strbuf_release(&buffer);
 +			if (expected_missing)
 +				return -1;
  			return error("invalid object %06o %s for '%.*s'",
  				mode, sha1_to_hex(sha1), entlen+baselen, path);
  		}
@@@ -390,14 -383,7 +392,14 @@@
  #endif
  	}
  
 -	if (dryrun)
 +	if (repair) {
 +		unsigned char sha1[20];
 +		hash_sha1_file(buffer.buf, buffer.len, tree_type, sha1);
 +		if (has_sha1_file(sha1))
 +			hashcpy(it->sha1, sha1);
 +		else
 +			to_invalidate = 1;
 +	} else if (dryrun)
  		hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
  	else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
  		strbuf_release(&buffer);