post-checkout hook, tests, and docs

diff --git a/builtin-write-tree.c b/builtin-write-tree.c
index 90fc1cfcf40d057cd654edd1454f56cd823efd66..b89d02efec813d33f8540d2a6d433a94ce1e0a31 100644 (file)
--- a/builtin-write-tree.c
+++ b/builtin-write-tree.c
@@ -18,7 +18,7 @@ int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
        /* We can't free this memory, it becomes part of a linked list parsed atexit() */
        struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
-       newfd = hold_lock_file_for_update(lock_file, get_index_file(), 0);
+       newfd = hold_locked_index(lock_file, 1);
 
        entries = read_cache();
        if (entries < 0)
@@ -36,8 +36,10 @@ int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
                        die("git-write-tree: error building trees");
                if (0 <= newfd) {
                        if (!write_cache(newfd, active_cache, active_nr)
-                                       && !close(newfd))
+                                       && !close(newfd)) {
                                commit_lock_file(lock_file);
+                               newfd = -1;
+                       }
                }
                /* Not being able to write is fine -- we are only interested
                 * in updating the cache-tree part, and if the next caller
@@ -50,11 +52,15 @@ int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
        if (prefix) {
                struct cache_tree *subtree =
                        cache_tree_find(active_cache_tree, prefix);
+               if (!subtree)
+                       die("git-write-tree: prefix %s not found", prefix);
                hashcpy(sha1, subtree->sha1);
        }
        else
                hashcpy(sha1, active_cache_tree->sha1);
 
+       if (0 <= newfd)
+               close(newfd);
        rollback_lock_file(lock_file);
 
        return 0;
@@ -66,6 +72,7 @@ int cmd_write_tree(int argc, const char **argv, const char *unused_prefix)
        const char *prefix = NULL;
        unsigned char sha1[20];
 
+       git_config(git_default_config);
        while (1 < argc) {
                const char *arg = argv[1];
                if (!strcmp(arg, "--missing-ok"))