git/builtin-read-tree.c
Alexandre Julliard db137fe91e read-tree: Fix regression with creation of a new index file.
Reading the index into an empty file has been broken by
5a56da5806, since it causes the existing
index to always be loaded first, and dies if it's an empty file:

$ GIT_INDEX_FILE=`mktemp` git read-tree master
fatal: index file smaller than expected

It breaks for instance committing from git.el. This patch reverts to the
previous behavior of only loading the index when merging it.

Signed-off-by: Alexandre Julliard <julliard@winehq.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-08-17 09:20:52 -07:00

196 lines
5.5 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
#include "object.h"
#include "tree.h"
#include "tree-walk.h"
#include "cache-tree.h"
#include "unpack-trees.h"
#include "dir.h"
#include "builtin.h"
#include "parse-options.h"
static int nr_trees;
static struct tree *trees[MAX_UNPACK_TREES];
static int list_tree(unsigned char *sha1)
{
struct tree *tree;
if (nr_trees >= MAX_UNPACK_TREES)
die("I cannot read more than %d trees", MAX_UNPACK_TREES);
tree = parse_tree_indirect(sha1);
if (!tree)
return -1;
trees[nr_trees++] = tree;
return 0;
}
static const char * const read_tree_usage[] = {
"git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
NULL
};
static int index_output_cb(const struct option *opt, const char *arg,
int unset)
{
set_alternate_index_output(arg);
return 0;
}
static int exclude_per_directory_cb(const struct option *opt, const char *arg,
int unset)
{
struct dir_struct *dir;
struct unpack_trees_options *opts;
opts = (struct unpack_trees_options *)opt->value;
if (opts->dir)
die("more than one --exclude-per-directory given.");
dir = xcalloc(1, sizeof(*opts->dir));
dir->flags |= DIR_SHOW_IGNORED;
dir->exclude_per_dir = arg;
opts->dir = dir;
/* We do not need to nor want to do read-directory
* here; we are merely interested in reusing the
* per directory ignore stack mechanism.
*/
return 0;
}
static struct lock_file lock_file;
int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
{
int i, newfd, stage = 0;
unsigned char sha1[20];
struct tree_desc t[MAX_UNPACK_TREES];
struct unpack_trees_options opts;
int prefix_set = 0;
const struct option read_tree_options[] = {
{ OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
"write resulting index to <FILE>",
PARSE_OPT_NONEG, index_output_cb },
OPT__VERBOSE(&opts.verbose_update),
OPT_GROUP("Merging"),
OPT_SET_INT('m', NULL, &opts.merge,
"perform a merge in addition to a read", 1),
OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
"3-way merge if no file level merging required", 1),
OPT_SET_INT(0, "aggressive", &opts.aggressive,
"3-way merge in presence of adds and removes", 1),
OPT_SET_INT(0, "reset", &opts.reset,
"same as -m, but discard unmerged entries", 1),
{ OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
"read the tree into the index under <subdirectory>/",
PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
OPT_SET_INT('u', NULL, &opts.update,
"update working tree with merge result", 1),
{ OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
"gitignore",
"allow explicitly ignored files to be overwritten",
PARSE_OPT_NONEG, exclude_per_directory_cb },
OPT_SET_INT('i', NULL, &opts.index_only,
"don't check the working tree after merging", 1),
OPT_END()
};
memset(&opts, 0, sizeof(opts));
opts.head_idx = -1;
opts.src_index = &the_index;
opts.dst_index = &the_index;
git_config(git_default_config, NULL);
newfd = hold_locked_index(&lock_file, 1);
argc = parse_options(argc, argv, unused_prefix, read_tree_options,
read_tree_usage, 0);
prefix_set = opts.prefix ? 1 : 0;
if (1 < opts.merge + opts.reset + prefix_set)
die("Which one? -m, --reset, or --prefix?");
if (opts.reset || opts.merge || opts.prefix) {
if (read_cache_unmerged() && (opts.prefix || opts.merge))
die("You need to resolve your current index first");
stage = opts.merge = 1;
}
for (i = 0; i < argc; i++) {
const char *arg = argv[i];
if (get_sha1(arg, sha1))
die("Not a valid object name %s", arg);
if (list_tree(sha1) < 0)
die("failed to unpack tree object %s", arg);
stage++;
}
if (1 < opts.index_only + opts.update)
die("-u and -i at the same time makes no sense");
if ((opts.update||opts.index_only) && !opts.merge)
die("%s is meaningless without -m, --reset, or --prefix",
opts.update ? "-u" : "-i");
if ((opts.dir && !opts.update))
die("--exclude-per-directory is meaningless unless -u");
if (opts.merge && !opts.index_only)
setup_work_tree();
if (opts.merge) {
if (stage < 2)
die("just how do you expect me to merge %d trees?", stage-1);
switch (stage - 1) {
case 1:
opts.fn = opts.prefix ? bind_merge : oneway_merge;
break;
case 2:
opts.fn = twoway_merge;
opts.initial_checkout = is_cache_unborn();
break;
case 3:
default:
opts.fn = threeway_merge;
break;
}
if (stage - 1 >= 3)
opts.head_idx = stage - 2;
else
opts.head_idx = 1;
}
cache_tree_free(&active_cache_tree);
for (i = 0; i < nr_trees; i++) {
struct tree *tree = trees[i];
parse_tree(tree);
init_tree_desc(t+i, tree->buffer, tree->size);
}
if (unpack_trees(nr_trees, t, &opts))
return 128;
/*
* When reading only one tree (either the most basic form,
* "-m ent" or "--reset ent" form), we can obtain a fully
* valid cache-tree because the index must match exactly
* what came from the tree.
*
* The same holds true if we are switching between two trees
* using read-tree -m A B. The index must match B after that.
*/
if (nr_trees == 1 && !opts.prefix)
prime_cache_tree(&active_cache_tree, trees[0]);
else if (nr_trees == 2 && opts.merge)
prime_cache_tree(&active_cache_tree, trees[1]);
if (write_cache(newfd, active_cache, active_nr) ||
commit_locked_index(&lock_file))
die("unable to write new index file");
return 0;
}