Merge branch 'tg/split-index-fixes' into maint

The split-index mode had a few corner case bugs fixed.

* tg/split-index-fixes:
  travis: run tests with GIT_TEST_SPLIT_INDEX
  split-index: don't write cache tree with null oid entries
  read-cache: fix reading the shared index for other repos

8 files changed, 48 insertions, 17 deletions

diff --git a/cache-tree.c b/cache-tree.c
index e03e72c34a..0dd6292a94 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -608,7 +608,7 @@ int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, co
 
 	hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 
-	entries = read_index_from(index_state, index_path);
+	entries = read_index_from(index_state, index_path, get_git_dir());
 	if (entries < 0) {
 		ret = WRITE_TREE_UNREADABLE_INDEX;
 		goto out;
diff --git a/cache.h b/cache.h
index d8b975a571..fd755c32cf 100644
--- a/cache.h
+++ b/cache.h
@@ -345,7 +345,8 @@ struct index_state {
 	struct split_index *split_index;
 	struct cache_time timestamp;
 	unsigned name_hash_initialized : 1,
-		 initialized : 1;
+		 initialized : 1,
+		 drop_cache_tree : 1;
 	struct hashmap name_hash;
 	struct hashmap dir_hash;
 	unsigned char sha1[20];
@@ -371,7 +372,7 @@ extern void free_name_hash(struct index_state *istate);
 #define active_cache_tree (the_index.cache_tree)
 
 #define read_cache() read_index(&the_index)
-#define read_cache_from(path) read_index_from(&the_index, (path))
+#define read_cache_from(path) read_index_from(&the_index, (path), (get_git_dir()))
 #define read_cache_preload(pathspec) read_index_preload(&the_index, (pathspec))
 #define is_cache_unborn() is_index_unborn(&the_index)
 #define read_cache_unmerged() read_index_unmerged(&the_index)
@@ -616,7 +617,8 @@ extern int read_index(struct index_state *);
 extern int read_index_preload(struct index_state *, const struct pathspec *pathspec);
 extern int do_read_index(struct index_state *istate, const char *path,
 			 int must_exist); /* for testting only! */
-extern int read_index_from(struct index_state *, const char *path);
+extern int read_index_from(struct index_state *, const char *path,
+			   const char *gitdir);
 extern int is_index_unborn(struct index_state *);
 extern int read_index_unmerged(struct index_state *);
 
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index d3a094603f..3e23e65f9e 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -9,6 +9,10 @@ ln -s $HOME/travis-cache/.prove t/.prove
 
 make --jobs=2
 make --quiet test
+if test "$jobname" = "linux-gcc"
+then
+	GIT_TEST_SPLIT_INDEX=YesPlease make --quiet test
+fi
 
 check_unignored_build_artifacts
 
diff --git a/read-cache.c b/read-cache.c
index 2eb81a66b9..d13ce83794 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1603,7 +1603,7 @@ int hold_locked_index(struct lock_file *lk, int lock_flags)
 
 int read_index(struct index_state *istate)
 {
-	return read_index_from(istate, get_index_file());
+	return read_index_from(istate, get_index_file(), get_git_dir());
 }
 
 static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
@@ -1863,20 +1863,19 @@ unmap:
  * This way, shared index can be removed if they have not been used
  * for some time.
  */
-static void freshen_shared_index(char *base_sha1_hex, int warn)
+static void freshen_shared_index(const char *shared_index, int warn)
 {
-	char *shared_index = git_pathdup("sharedindex.%s", base_sha1_hex);
 	if (!check_and_freshen_file(shared_index, 1) && warn)
 		warning("could not freshen shared index '%s'", shared_index);
-	free(shared_index);
 }
 
-int read_index_from(struct index_state *istate, const char *path)
+int read_index_from(struct index_state *istate, const char *path,
+		    const char *gitdir)
 {
 	struct split_index *split_index;
 	int ret;
 	char *base_sha1_hex;
-	const char *base_path;
+	char *base_path;
 
 	/* istate->initialized covers both .git/index and .git/sharedindex.xxx */
 	if (istate->initialized)
@@ -1896,16 +1895,17 @@ int read_index_from(struct index_state *istate, const char *path)
 		split_index->base = xcalloc(1, sizeof(*split_index->base));
 
 	base_sha1_hex = sha1_to_hex(split_index->base_sha1);
-	base_path = git_path("sharedindex.%s", base_sha1_hex);
+	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_sha1_hex);
 	ret = do_read_index(split_index->base, base_path, 1);
 	if (hashcmp(split_index->base_sha1, split_index->base->sha1))
 		die("broken index, expect %s in %s, got %s",
 		    base_sha1_hex, base_path,
 		    sha1_to_hex(split_index->base->sha1));
 
-	freshen_shared_index(base_sha1_hex, 0);
+	freshen_shared_index(base_path, 0);
 	merge_base_index(istate);
 	post_read_index_from(istate);
+	free(base_path);
 	return ret;
 }
 
@@ -2243,7 +2243,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 	struct stat st;
 	struct ondisk_cache_entry_extended ondisk;
 	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
-	int drop_cache_tree = 0;
+	int drop_cache_tree = istate->drop_cache_tree;
 
 	for (i = removed = extended = 0; i < entries; i++) {
 		if (cache[i]->ce_flags & CE_REMOVE)
@@ -2573,8 +2573,11 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	ret = write_split_index(istate, lock, flags);
 
 	/* Freshen the shared index only if the split-index was written */
-	if (!ret && !new_shared_index)
-		freshen_shared_index(sha1_to_hex(si->base_sha1), 1);
+	if (!ret && !new_shared_index) {
+		const char *shared_index = git_path("sharedindex.%s",
+						    sha1_to_hex(si->base_sha1));
+		freshen_shared_index(shared_index, 1);
+	}
 
 out:
 	if (flags & COMMIT_LOCK)
diff --git a/repository.c b/repository.c
index f66fcb1342..4ffbe9bc94 100644
--- a/repository.c
+++ b/repository.c
@@ -236,5 +236,5 @@ int repo_read_index(struct repository *repo)
 	if (!repo->index)
 		repo->index = xcalloc(1, sizeof(*repo->index));
 
-	return read_index_from(repo->index, repo->index_file);
+	return read_index_from(repo->index, repo->index_file, repo->gitdir);
 }
diff --git a/revision.c b/revision.c
index 1f7454c947..a2ba54459d 100644
--- a/revision.c
+++ b/revision.c
@@ -1352,7 +1352,8 @@ void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
 			continue; /* current index already taken care of */
 
 		if (read_index_from(&istate,
-				    worktree_git_path(wt, "index")) > 0)
+				    worktree_git_path(wt, "index"),
+				    get_worktree_git_dir(wt)) > 0)
 			do_add_index_objects_to_pending(revs, &istate);
 		discard_index(&istate);
 	}
diff --git a/split-index.c b/split-index.c
index 83e39ec8d7..284d04d67f 100644
--- a/split-index.c
+++ b/split-index.c
@@ -238,6 +238,8 @@ void prepare_to_write_split_index(struct index_state *istate)
 				ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 				entries[nr_entries++] = ce;
 			}
+			if (is_null_oid(&ce->oid))
+				istate->drop_cache_tree = 1;
 		}
 	}
 
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index af9b847761..c087b63367 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -401,4 +401,23 @@ done <<\EOF
 0642 -rw-r---w-
 EOF
 
+test_expect_success 'writing split index with null sha1 does not write cache tree' '
+	git config core.splitIndex true &&
+	git config splitIndex.maxPercentChange 0 &&
+	git commit -m "commit" &&
+	{
+		git ls-tree HEAD &&
+		printf "160000 commit $_z40\\tbroken\\n"
+	} >broken-tree &&
+	echo "add broken entry" >msg &&
+
+	tree=$(git mktree <broken-tree) &&
+	test_tick &&
+	commit=$(git commit-tree $tree -p HEAD <msg) &&
+	git update-ref HEAD "$commit" &&
+	GIT_ALLOW_NULL_SHA1=1 git reset --hard &&
+	(test-dump-cache-tree >cache-tree.out || true) &&
+	test_line_count = 0 cache-tree.out
+'
+
 test_done