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git/builtin.h
Jeff King e54501004a diff: do not use null sha1 as a sentinel value
The diff code represents paths using the diff_filespec
struct. This struct has a sha1 to represent the sha1 of the
content at that path, as well as a sha1_valid member which
indicates whether its sha1 field is actually useful. If
sha1_valid is not true, then the filespec represents a
working tree file (e.g., for the no-index case, or for when
the index is not up-to-date).

The diff_filespec is only used internally, though. At the
interfaces to the diff subsystem, callers feed the sha1
directly, and we create a diff_filespec from it. It's at
that point that we look at the sha1 and decide whether it is
valid or not; callers may pass the null sha1 as a sentinel
value to indicate that it is not.

We should not typically see the null sha1 coming from any
other source (e.g., in the index itself, or from a tree).
However, a corrupt tree might have a null sha1, which would
cause "diff --patch" to accidentally diff the working tree
version of a file instead of treating it as a blob.

This patch extends the edges of the diff interface to accept
a "sha1_valid" flag whenever we accept a sha1, and to use
that flag when creating a filespec. In some cases, this
means passing the flag through several layers, making the
code change larger than would be desirable.

One alternative would be to simply die() upon seeing
corrupted trees with null sha1s. However, this fix more
directly addresses the problem (while bogus sha1s in a tree
are probably a bad thing, it is really the sentinel
confusion sending us down the wrong code path that is what
makes it devastating). And it means that git is more capable
of examining and debugging these corrupted trees. For
example, you can still "diff --raw" such a tree to find out
when the bogus entry was introduced; you just cannot do a
"--patch" diff (just as you could not with any other
corrupted tree, as we do not have any content to diff).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-29 15:04:32 -07:00

155 lines
9.0 KiB
C

#ifndef BUILTIN_H
#define BUILTIN_H
#include "git-compat-util.h"
#include "strbuf.h"
#include "cache.h"
#include "commit.h"
#include "notes.h"
#define DEFAULT_MERGE_LOG_LEN 20
extern const char git_version_string[];
extern const char git_usage_string[];
extern const char git_more_info_string[];
extern void prune_packed_objects(int);
struct fmt_merge_msg_opts {
unsigned add_title:1;
int shortlog_len;
};
extern int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
struct fmt_merge_msg_opts *);
extern void commit_notes(struct notes_tree *t, const char *msg);
struct notes_rewrite_cfg {
struct notes_tree **trees;
const char *cmd;
int enabled;
combine_notes_fn combine;
struct string_list *refs;
int refs_from_env;
int mode_from_env;
};
combine_notes_fn parse_combine_notes_fn(const char *v);
struct notes_rewrite_cfg *init_copy_notes_for_rewrite(const char *cmd);
int copy_note_for_rewrite(struct notes_rewrite_cfg *c,
const unsigned char *from_obj, const unsigned char *to_obj);
void finish_copy_notes_for_rewrite(struct notes_rewrite_cfg *c);
extern int check_pager_config(const char *cmd);
extern int textconv_object(const char *path, unsigned mode, const unsigned char *sha1, int sha1_valid, char **buf, unsigned long *buf_size);
extern int cmd_add(int argc, const char **argv, const char *prefix);
extern int cmd_annotate(int argc, const char **argv, const char *prefix);
extern int cmd_apply(int argc, const char **argv, const char *prefix);
extern int cmd_archive(int argc, const char **argv, const char *prefix);
extern int cmd_bisect__helper(int argc, const char **argv, const char *prefix);
extern int cmd_blame(int argc, const char **argv, const char *prefix);
extern int cmd_branch(int argc, const char **argv, const char *prefix);
extern int cmd_bundle(int argc, const char **argv, const char *prefix);
extern int cmd_cat_file(int argc, const char **argv, const char *prefix);
extern int cmd_checkout(int argc, const char **argv, const char *prefix);
extern int cmd_checkout_index(int argc, const char **argv, const char *prefix);
extern int cmd_check_attr(int argc, const char **argv, const char *prefix);
extern int cmd_check_ref_format(int argc, const char **argv, const char *prefix);
extern int cmd_cherry(int argc, const char **argv, const char *prefix);
extern int cmd_cherry_pick(int argc, const char **argv, const char *prefix);
extern int cmd_clone(int argc, const char **argv, const char *prefix);
extern int cmd_clean(int argc, const char **argv, const char *prefix);
extern int cmd_commit(int argc, const char **argv, const char *prefix);
extern int cmd_commit_tree(int argc, const char **argv, const char *prefix);
extern int cmd_config(int argc, const char **argv, const char *prefix);
extern int cmd_count_objects(int argc, const char **argv, const char *prefix);
extern int cmd_describe(int argc, const char **argv, const char *prefix);
extern int cmd_diff_files(int argc, const char **argv, const char *prefix);
extern int cmd_diff_index(int argc, const char **argv, const char *prefix);
extern int cmd_diff(int argc, const char **argv, const char *prefix);
extern int cmd_diff_tree(int argc, const char **argv, const char *prefix);
extern int cmd_fast_export(int argc, const char **argv, const char *prefix);
extern int cmd_fetch(int argc, const char **argv, const char *prefix);
extern int cmd_fetch_pack(int argc, const char **argv, const char *prefix);
extern int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix);
extern int cmd_for_each_ref(int argc, const char **argv, const char *prefix);
extern int cmd_format_patch(int argc, const char **argv, const char *prefix);
extern int cmd_fsck(int argc, const char **argv, const char *prefix);
extern int cmd_gc(int argc, const char **argv, const char *prefix);
extern int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix);
extern int cmd_grep(int argc, const char **argv, const char *prefix);
extern int cmd_hash_object(int argc, const char **argv, const char *prefix);
extern int cmd_help(int argc, const char **argv, const char *prefix);
extern int cmd_http_fetch(int argc, const char **argv, const char *prefix);
extern int cmd_index_pack(int argc, const char **argv, const char *prefix);
extern int cmd_init_db(int argc, const char **argv, const char *prefix);
extern int cmd_log(int argc, const char **argv, const char *prefix);
extern int cmd_log_reflog(int argc, const char **argv, const char *prefix);
extern int cmd_ls_files(int argc, const char **argv, const char *prefix);
extern int cmd_ls_tree(int argc, const char **argv, const char *prefix);
extern int cmd_ls_remote(int argc, const char **argv, const char *prefix);
extern int cmd_mailinfo(int argc, const char **argv, const char *prefix);
extern int cmd_mailsplit(int argc, const char **argv, const char *prefix);
extern int cmd_merge(int argc, const char **argv, const char *prefix);
extern int cmd_merge_base(int argc, const char **argv, const char *prefix);
extern int cmd_merge_index(int argc, const char **argv, const char *prefix);
extern int cmd_merge_ours(int argc, const char **argv, const char *prefix);
extern int cmd_merge_file(int argc, const char **argv, const char *prefix);
extern int cmd_merge_recursive(int argc, const char **argv, const char *prefix);
extern int cmd_merge_tree(int argc, const char **argv, const char *prefix);
extern int cmd_mktag(int argc, const char **argv, const char *prefix);
extern int cmd_mktree(int argc, const char **argv, const char *prefix);
extern int cmd_mv(int argc, const char **argv, const char *prefix);
extern int cmd_name_rev(int argc, const char **argv, const char *prefix);
extern int cmd_notes(int argc, const char **argv, const char *prefix);
extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
extern int cmd_pickaxe(int argc, const char **argv, const char *prefix);
extern int cmd_prune(int argc, const char **argv, const char *prefix);
extern int cmd_prune_packed(int argc, const char **argv, const char *prefix);
extern int cmd_push(int argc, const char **argv, const char *prefix);
extern int cmd_read_tree(int argc, const char **argv, const char *prefix);
extern int cmd_receive_pack(int argc, const char **argv, const char *prefix);
extern int cmd_reflog(int argc, const char **argv, const char *prefix);
extern int cmd_remote(int argc, const char **argv, const char *prefix);
extern int cmd_remote_ext(int argc, const char **argv, const char *prefix);
extern int cmd_remote_fd(int argc, const char **argv, const char *prefix);
extern int cmd_repo_config(int argc, const char **argv, const char *prefix);
extern int cmd_rerere(int argc, const char **argv, const char *prefix);
extern int cmd_reset(int argc, const char **argv, const char *prefix);
extern int cmd_rev_list(int argc, const char **argv, const char *prefix);
extern int cmd_rev_parse(int argc, const char **argv, const char *prefix);
extern int cmd_revert(int argc, const char **argv, const char *prefix);
extern int cmd_rm(int argc, const char **argv, const char *prefix);
extern int cmd_send_pack(int argc, const char **argv, const char *prefix);
extern int cmd_shortlog(int argc, const char **argv, const char *prefix);
extern int cmd_show(int argc, const char **argv, const char *prefix);
extern int cmd_show_branch(int argc, const char **argv, const char *prefix);
extern int cmd_status(int argc, const char **argv, const char *prefix);
extern int cmd_stripspace(int argc, const char **argv, const char *prefix);
extern int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
extern int cmd_tag(int argc, const char **argv, const char *prefix);
extern int cmd_tar_tree(int argc, const char **argv, const char *prefix);
extern int cmd_unpack_file(int argc, const char **argv, const char *prefix);
extern int cmd_unpack_objects(int argc, const char **argv, const char *prefix);
extern int cmd_update_index(int argc, const char **argv, const char *prefix);
extern int cmd_update_ref(int argc, const char **argv, const char *prefix);
extern int cmd_update_server_info(int argc, const char **argv, const char *prefix);
extern int cmd_upload_archive(int argc, const char **argv, const char *prefix);
extern int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix);
extern int cmd_upload_tar(int argc, const char **argv, const char *prefix);
extern int cmd_var(int argc, const char **argv, const char *prefix);
extern int cmd_verify_tag(int argc, const char **argv, const char *prefix);
extern int cmd_version(int argc, const char **argv, const char *prefix);
extern int cmd_whatchanged(int argc, const char **argv, const char *prefix);
extern int cmd_write_tree(int argc, const char **argv, const char *prefix);
extern int cmd_verify_pack(int argc, const char **argv, const char *prefix);
extern int cmd_show_ref(int argc, const char **argv, const char *prefix);
extern int cmd_pack_refs(int argc, const char **argv, const char *prefix);
extern int cmd_replace(int argc, const char **argv, const char *prefix);
#endif