git/builtin/read-tree.c
Jens Lehmann ea5070c91f Teach read-tree the -n|--dry-run option
The option can be used to check if read-tree with the same set of other
options like "-m" and "-u" would succeed without actually changing either
the index or the working tree.

The relevant tests in the t10?? range were extended to do a read-tree -n
before the real read-tree to make sure neither the index nor any local
files were changed with -n and the same exit code as without -n is
returned. The helper functions added for that purpose reside in the new
t/lib-read-tree.sh file.

The only exception is #13 in t1004 ("unlinking an un-unlink-able
symlink"). As this is an issue of wrong directory permissions it is not
detected with -n.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-05-25 15:04:25 -07:00

240 lines
6.7 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"
#include "resolve-undo.h"
static int nr_trees;
static int read_empty;
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]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <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 void debug_stage(const char *label, struct cache_entry *ce,
struct unpack_trees_options *o)
{
printf("%s ", label);
if (!ce)
printf("(missing)\n");
else if (ce == o->df_conflict_entry)
printf("(conflict)\n");
else
printf("%06o #%d %s %.8s\n",
ce->ce_mode, ce_stage(ce), ce->name,
sha1_to_hex(ce->sha1));
}
static int debug_merge(struct cache_entry **stages, struct unpack_trees_options *o)
{
int i;
printf("* %d-way merge\n", o->merge_size);
debug_stage("index", stages[0], o);
for (i = 1; i <= o->merge_size; i++) {
char buf[24];
sprintf(buf, "ent#%d", i);
debug_stage(buf, stages[i], o);
}
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_SET_INT(0, "empty", &read_empty,
"only empty the index", 1),
OPT__VERBOSE(&opts.verbose_update, "be verbose"),
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__DRY_RUN(&opts.dry_run, "don't update the index or the work tree"),
OPT_SET_INT(0, "no-sparse-checkout", &opts.skip_sparse_checkout,
"skip applying sparse checkout filter", 1),
OPT_SET_INT(0, "debug-unpack", &opts.debug_unpack,
"debug unpack-trees", 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);
argc = parse_options(argc, argv, unused_prefix, read_tree_options,
read_tree_usage, 0);
newfd = hold_locked_index(&lock_file, 1);
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;
}
resolve_undo_clear();
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 (nr_trees == 0 && !read_empty)
warning("read-tree: emptying the index with no arguments is deprecated; use --empty");
else if (nr_trees > 0 && read_empty)
die("passing trees as arguments contradicts --empty");
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;
}
if (opts.debug_unpack)
opts.fn = debug_merge;
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;
if (opts.debug_unpack || opts.dry_run)
return 0; /* do not write the index out */
/*
* 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.
*/
if (nr_trees == 1 && !opts.prefix)
prime_cache_tree(&active_cache_tree, trees[0]);
if (write_cache(newfd, active_cache, active_nr) ||
commit_locked_index(&lock_file))
die("unable to write new index file");
return 0;
}