2 * "git difftool" builtin command
4 * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
5 * git-difftool--helper script.
7 * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
8 * The GIT_DIFF* variables are exported for use by git-difftool--helper.
10 * Any arguments that are unknown to this script are forwarded to 'git diff'.
12 * Copyright (C) 2016 Johannes Schindelin
14 #define USE_THE_INDEX_VARIABLE
19 #include "run-command.h"
20 #include "environment.h"
24 #include "parse-options.h"
25 #include "read-cache-ll.h"
26 #include "sparse-index.h"
30 #include "object-file.h"
31 #include "object-store.h"
37 static int trust_exit_code
;
39 static const char *const builtin_difftool_usage
[] = {
40 N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
44 static int difftool_config(const char *var
, const char *value
, void *cb
)
46 if (!strcmp(var
, "difftool.trustexitcode")) {
47 trust_exit_code
= git_config_bool(var
, value
);
51 return git_default_config(var
, value
, cb
);
54 static int print_tool_help(void)
56 struct child_process cmd
= CHILD_PROCESS_INIT
;
59 strvec_pushl(&cmd
.args
, "mergetool", "--tool-help=diff", NULL
);
60 return run_command(&cmd
);
63 static int parse_index_info(char *p
, int *mode1
, int *mode2
,
64 struct object_id
*oid1
, struct object_id
*oid2
,
68 return error("expected ':', got '%c'", *p
);
69 *mode1
= (int)strtol(p
+ 1, &p
, 8);
71 return error("expected ' ', got '%c'", *p
);
72 *mode2
= (int)strtol(p
+ 1, &p
, 8);
74 return error("expected ' ', got '%c'", *p
);
75 if (parse_oid_hex(++p
, oid1
, (const char **)&p
))
76 return error("expected object ID, got '%s'", p
);
78 return error("expected ' ', got '%c'", *p
);
79 if (parse_oid_hex(++p
, oid2
, (const char **)&p
))
80 return error("expected object ID, got '%s'", p
);
82 return error("expected ' ', got '%c'", *p
);
85 return error("missing status");
86 if (p
[1] && !isdigit(p
[1]))
87 return error("unexpected trailer: '%s'", p
+ 1);
92 * Remove any trailing slash from $workdir
93 * before starting to avoid double slashes in symlink targets.
95 static void add_path(struct strbuf
*buf
, size_t base_len
, const char *path
)
97 strbuf_setlen(buf
, base_len
);
98 if (buf
->len
&& buf
->buf
[buf
->len
- 1] != '/')
99 strbuf_addch(buf
, '/');
100 strbuf_addstr(buf
, path
);
104 * Determine whether we can simply reuse the file in the worktree.
106 static int use_wt_file(const char *workdir
, const char *name
,
107 struct object_id
*oid
)
109 struct strbuf buf
= STRBUF_INIT
;
113 strbuf_addstr(&buf
, workdir
);
114 add_path(&buf
, buf
.len
, name
);
116 if (!lstat(buf
.buf
, &st
) && !S_ISLNK(st
.st_mode
)) {
117 struct object_id wt_oid
;
118 int fd
= open(buf
.buf
, O_RDONLY
);
121 !index_fd(&the_index
, &wt_oid
, fd
, &st
, OBJ_BLOB
, name
, 0)) {
122 if (is_null_oid(oid
)) {
123 oidcpy(oid
, &wt_oid
);
125 } else if (oideq(oid
, &wt_oid
))
130 strbuf_release(&buf
);
135 struct working_tree_entry
{
136 struct hashmap_entry entry
;
137 char path
[FLEX_ARRAY
];
140 static int working_tree_entry_cmp(const void *cmp_data UNUSED
,
141 const struct hashmap_entry
*eptr
,
142 const struct hashmap_entry
*entry_or_key
,
143 const void *keydata UNUSED
)
145 const struct working_tree_entry
*a
, *b
;
147 a
= container_of(eptr
, const struct working_tree_entry
, entry
);
148 b
= container_of(entry_or_key
, const struct working_tree_entry
, entry
);
150 return strcmp(a
->path
, b
->path
);
154 * The `left` and `right` entries hold paths for the symlinks hashmap,
155 * and a SHA-1 surrounded by brief text for submodules.
158 struct hashmap_entry entry
;
159 char left
[PATH_MAX
], right
[PATH_MAX
];
160 const char path
[FLEX_ARRAY
];
163 static int pair_cmp(const void *cmp_data UNUSED
,
164 const struct hashmap_entry
*eptr
,
165 const struct hashmap_entry
*entry_or_key
,
166 const void *keydata UNUSED
)
168 const struct pair_entry
*a
, *b
;
170 a
= container_of(eptr
, const struct pair_entry
, entry
);
171 b
= container_of(entry_or_key
, const struct pair_entry
, entry
);
173 return strcmp(a
->path
, b
->path
);
176 static void add_left_or_right(struct hashmap
*map
, const char *path
,
177 const char *content
, int is_right
)
179 struct pair_entry
*e
, *existing
;
181 FLEX_ALLOC_STR(e
, path
, path
);
182 hashmap_entry_init(&e
->entry
, strhash(path
));
183 existing
= hashmap_get_entry(map
, e
, entry
, NULL
);
188 e
->left
[0] = e
->right
[0] = '\0';
189 hashmap_add(map
, &e
->entry
);
191 strlcpy(is_right
? e
->right
: e
->left
, content
, PATH_MAX
);
195 struct hashmap_entry entry
;
196 char path
[FLEX_ARRAY
];
199 static int path_entry_cmp(const void *cmp_data UNUSED
,
200 const struct hashmap_entry
*eptr
,
201 const struct hashmap_entry
*entry_or_key
,
204 const struct path_entry
*a
, *b
;
206 a
= container_of(eptr
, const struct path_entry
, entry
);
207 b
= container_of(entry_or_key
, const struct path_entry
, entry
);
209 return strcmp(a
->path
, key
? key
: b
->path
);
212 static void changed_files(struct hashmap
*result
, const char *index_path
,
215 struct child_process update_index
= CHILD_PROCESS_INIT
;
216 struct child_process diff_files
= CHILD_PROCESS_INIT
;
217 struct strbuf buf
= STRBUF_INIT
;
218 const char *git_dir
= absolute_path(get_git_dir());
221 strvec_pushl(&update_index
.args
,
222 "--git-dir", git_dir
, "--work-tree", workdir
,
223 "update-index", "--really-refresh", "-q",
225 update_index
.no_stdin
= 1;
226 update_index
.no_stdout
= 1;
227 update_index
.no_stderr
= 1;
228 update_index
.git_cmd
= 1;
229 update_index
.use_shell
= 0;
230 update_index
.clean_on_exit
= 1;
231 update_index
.dir
= workdir
;
232 strvec_pushf(&update_index
.env
, "GIT_INDEX_FILE=%s", index_path
);
233 /* Ignore any errors of update-index */
234 run_command(&update_index
);
236 strvec_pushl(&diff_files
.args
,
237 "--git-dir", git_dir
, "--work-tree", workdir
,
238 "diff-files", "--name-only", "-z", NULL
);
239 diff_files
.no_stdin
= 1;
240 diff_files
.git_cmd
= 1;
241 diff_files
.use_shell
= 0;
242 diff_files
.clean_on_exit
= 1;
244 diff_files
.dir
= workdir
;
245 strvec_pushf(&diff_files
.env
, "GIT_INDEX_FILE=%s", index_path
);
246 if (start_command(&diff_files
))
247 die("could not obtain raw diff");
248 fp
= xfdopen(diff_files
.out
, "r");
249 while (!strbuf_getline_nul(&buf
, fp
)) {
250 struct path_entry
*entry
;
251 FLEX_ALLOC_STR(entry
, path
, buf
.buf
);
252 hashmap_entry_init(&entry
->entry
, strhash(buf
.buf
));
253 hashmap_add(result
, &entry
->entry
);
256 if (finish_command(&diff_files
))
257 die("diff-files did not exit properly");
258 strbuf_release(&buf
);
261 static int ensure_leading_directories(char *path
)
263 switch (safe_create_leading_directories(path
)) {
268 return error(_("could not create leading directories "
274 * Unconditional writing of a plain regular file is what
275 * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
276 * temporary directories to be fed to a Git-unaware tool that knows how to
277 * show a diff of two directories (e.g. "diff -r A B").
279 * Because the tool is Git-unaware, if a symbolic link appears in either of
280 * these temporary directories, it will try to dereference and show the
281 * difference of the target of the symbolic link, which is not what we want,
282 * as the goal of the dir-diff mode is to produce an output that is logically
283 * equivalent to what "git diff" produces.
285 * Most importantly, we want to get textual comparison of the result of the
286 * readlink(2). get_symlink() provides that---it returns the contents of
287 * the symlink that gets written to a regular file to force the external tool
288 * to compare the readlink(2) result as text, even on a filesystem that is
289 * capable of doing a symbolic link.
291 static char *get_symlink(const struct object_id
*oid
, const char *path
)
294 if (is_null_oid(oid
)) {
295 /* The symlink is unknown to Git so read from the filesystem */
296 struct strbuf link
= STRBUF_INIT
;
298 if (strbuf_readlink(&link
, path
, strlen(path
)))
299 die(_("could not read symlink %s"), path
);
300 } else if (strbuf_read_file(&link
, path
, 128))
301 die(_("could not read symlink file %s"), path
);
303 data
= strbuf_detach(&link
, NULL
);
305 enum object_type type
;
307 data
= repo_read_object_file(the_repository
, oid
, &type
,
310 die(_("could not read object %s for symlink %s"),
311 oid_to_hex(oid
), path
);
317 static int checkout_path(unsigned mode
, struct object_id
*oid
,
318 const char *path
, const struct checkout
*state
)
320 struct cache_entry
*ce
;
323 ce
= make_transient_cache_entry(mode
, oid
, path
, 0, NULL
);
324 ret
= checkout_entry(ce
, state
, NULL
, NULL
);
326 discard_cache_entry(ce
);
330 static void write_file_in_directory(struct strbuf
*dir
, size_t dir_len
,
331 const char *path
, const char *content
)
333 add_path(dir
, dir_len
, path
);
334 ensure_leading_directories(dir
->buf
);
336 write_file(dir
->buf
, "%s", content
);
339 /* Write the file contents for the left and right sides of the difftool
340 * dir-diff representation for submodules and symlinks. Symlinks and submodules
341 * are written as regular text files so that external diff tools can diff them
342 * as text files, resulting in behavior that is analogous to to what "git diff"
343 * displays for symlink and submodule diffs.
345 static void write_standin_files(struct pair_entry
*entry
,
346 struct strbuf
*ldir
, size_t ldir_len
,
347 struct strbuf
*rdir
, size_t rdir_len
)
350 write_file_in_directory(ldir
, ldir_len
, entry
->path
, entry
->left
);
352 write_file_in_directory(rdir
, rdir_len
, entry
->path
, entry
->right
);
355 static int run_dir_diff(const char *extcmd
, int symlinks
, const char *prefix
,
356 struct child_process
*child
)
358 struct strbuf info
= STRBUF_INIT
, lpath
= STRBUF_INIT
;
359 struct strbuf rpath
= STRBUF_INIT
, buf
= STRBUF_INIT
;
360 struct strbuf ldir
= STRBUF_INIT
, rdir
= STRBUF_INIT
;
361 struct strbuf wtdir
= STRBUF_INIT
;
362 struct strbuf tmpdir
= STRBUF_INIT
;
363 char *lbase_dir
= NULL
, *rbase_dir
= NULL
;
364 size_t ldir_len
, rdir_len
, wtdir_len
;
365 const char *workdir
, *tmp
;
368 struct hashmap working_tree_dups
= HASHMAP_INIT(working_tree_entry_cmp
,
370 struct hashmap submodules
= HASHMAP_INIT(pair_cmp
, NULL
);
371 struct hashmap symlinks2
= HASHMAP_INIT(pair_cmp
, NULL
);
372 struct hashmap_iter iter
;
373 struct pair_entry
*entry
;
374 struct index_state wtindex
= INDEX_STATE_INIT(the_repository
);
375 struct checkout lstate
, rstate
;
377 struct child_process cmd
= CHILD_PROCESS_INIT
;
378 struct hashmap wt_modified
, tmp_modified
;
379 int indices_loaded
= 0;
381 workdir
= get_git_work_tree();
383 /* Setup temp directories */
384 tmp
= getenv("TMPDIR");
385 strbuf_add_absolute_path(&tmpdir
, tmp
? tmp
: "/tmp");
386 strbuf_trim_trailing_dir_sep(&tmpdir
);
387 strbuf_addstr(&tmpdir
, "/git-difftool.XXXXXX");
388 if (!mkdtemp(tmpdir
.buf
)) {
389 ret
= error("could not create '%s'", tmpdir
.buf
);
392 strbuf_addf(&ldir
, "%s/left/", tmpdir
.buf
);
393 strbuf_addf(&rdir
, "%s/right/", tmpdir
.buf
);
394 strbuf_addstr(&wtdir
, workdir
);
395 if (!wtdir
.len
|| !is_dir_sep(wtdir
.buf
[wtdir
.len
- 1]))
396 strbuf_addch(&wtdir
, '/');
397 mkdir(ldir
.buf
, 0700);
398 mkdir(rdir
.buf
, 0700);
400 memset(&lstate
, 0, sizeof(lstate
));
401 lstate
.base_dir
= lbase_dir
= xstrdup(ldir
.buf
);
402 lstate
.base_dir_len
= ldir
.len
;
404 memset(&rstate
, 0, sizeof(rstate
));
405 rstate
.base_dir
= rbase_dir
= xstrdup(rdir
.buf
);
406 rstate
.base_dir_len
= rdir
.len
;
411 wtdir_len
= wtdir
.len
;
415 child
->use_shell
= 0;
416 child
->clean_on_exit
= 1;
419 if (start_command(child
))
420 die("could not obtain raw diff");
421 fp
= xfdopen(child
->out
, "r");
423 /* Build index info for left and right sides of the diff */
425 while (!strbuf_getline_nul(&info
, fp
)) {
427 struct object_id loid
, roid
;
429 const char *src_path
, *dst_path
;
431 if (starts_with(info
.buf
, "::"))
432 die(N_("combined diff formats ('-c' and '--cc') are "
434 "directory diff mode ('-d' and '--dir-diff')."));
436 if (parse_index_info(info
.buf
, &lmode
, &rmode
, &loid
, &roid
,
439 if (strbuf_getline_nul(&lpath
, fp
))
441 src_path
= lpath
.buf
;
444 if (status
!= 'C' && status
!= 'R') {
447 if (strbuf_getline_nul(&rpath
, fp
))
449 dst_path
= rpath
.buf
;
452 if (S_ISGITLINK(lmode
) || S_ISGITLINK(rmode
)) {
454 strbuf_addf(&buf
, "Subproject commit %s",
456 add_left_or_right(&submodules
, src_path
, buf
.buf
, 0);
458 strbuf_addf(&buf
, "Subproject commit %s",
460 if (oideq(&loid
, &roid
))
461 strbuf_addstr(&buf
, "-dirty");
462 add_left_or_right(&submodules
, dst_path
, buf
.buf
, 1);
466 if (S_ISLNK(lmode
)) {
467 char *content
= get_symlink(&loid
, src_path
);
468 add_left_or_right(&symlinks2
, src_path
, content
, 0);
472 if (S_ISLNK(rmode
)) {
473 char *content
= get_symlink(&roid
, dst_path
);
474 add_left_or_right(&symlinks2
, dst_path
, content
, 1);
478 if (lmode
&& status
!= 'C') {
479 if (checkout_path(lmode
, &loid
, src_path
, &lstate
)) {
480 ret
= error("could not write '%s'", src_path
);
485 if (rmode
&& !S_ISLNK(rmode
)) {
486 struct working_tree_entry
*entry
;
488 /* Avoid duplicate working_tree entries */
489 FLEX_ALLOC_STR(entry
, path
, dst_path
);
490 hashmap_entry_init(&entry
->entry
, strhash(dst_path
));
491 if (hashmap_get(&working_tree_dups
, &entry
->entry
,
496 hashmap_add(&working_tree_dups
, &entry
->entry
);
498 if (!use_wt_file(workdir
, dst_path
, &roid
)) {
499 if (checkout_path(rmode
, &roid
, dst_path
,
501 ret
= error("could not write '%s'",
505 } else if (!is_null_oid(&roid
)) {
507 * Changes in the working tree need special
508 * treatment since they are not part of the
511 struct cache_entry
*ce2
=
512 make_cache_entry(&wtindex
, rmode
, &roid
,
515 add_index_entry(&wtindex
, ce2
,
516 ADD_CACHE_JUST_APPEND
);
518 add_path(&rdir
, rdir_len
, dst_path
);
519 if (ensure_leading_directories(rdir
.buf
)) {
520 ret
= error("could not create "
521 "directory for '%s'",
525 add_path(&wtdir
, wtdir_len
, dst_path
);
527 if (symlink(wtdir
.buf
, rdir
.buf
)) {
528 ret
= error_errno("could not symlink '%s' to '%s'", wtdir
.buf
, rdir
.buf
);
533 if (stat(wtdir
.buf
, &st
))
535 if (copy_file(rdir
.buf
, wtdir
.buf
,
537 ret
= error("could not copy '%s' to '%s'", wtdir
.buf
, rdir
.buf
);
547 if (finish_command(child
)) {
548 ret
= error("error occurred running diff --raw");
556 * Changes to submodules require special treatment.This loop writes a
557 * temporary file to both the left and right directories to show the
558 * change in the recorded SHA1 for the submodule.
560 hashmap_for_each_entry(&submodules
, &iter
, entry
,
561 entry
/* member name */) {
562 write_standin_files(entry
, &ldir
, ldir_len
, &rdir
, rdir_len
);
566 * Symbolic links require special treatment. The standard "git diff"
567 * shows only the link itself, not the contents of the link target.
568 * This loop replicates that behavior.
570 hashmap_for_each_entry(&symlinks2
, &iter
, entry
,
571 entry
/* member name */) {
573 write_standin_files(entry
, &ldir
, ldir_len
, &rdir
, rdir_len
);
576 strbuf_setlen(&ldir
, ldir_len
);
577 strbuf_setlen(&rdir
, rdir_len
);
580 strvec_push(&cmd
.args
, extcmd
);
582 strvec_push(&cmd
.args
, "difftool--helper");
584 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
586 strvec_pushl(&cmd
.args
, ldir
.buf
, rdir
.buf
, NULL
);
587 ret
= run_command(&cmd
);
589 /* TODO: audit for interaction with sparse-index. */
590 ensure_full_index(&wtindex
);
593 * If the diff includes working copy files and those
594 * files were modified during the diff, then the changes
595 * should be copied back to the working tree.
596 * Do not copy back files when symlinks are used and the
597 * external tool did not replace the original link with a file.
599 * These hashes are loaded lazily since they aren't needed
600 * in the common case of --symlinks and the difftool updating
601 * files through the symlink.
603 hashmap_init(&wt_modified
, path_entry_cmp
, NULL
, wtindex
.cache_nr
);
604 hashmap_init(&tmp_modified
, path_entry_cmp
, NULL
, wtindex
.cache_nr
);
606 for (i
= 0; i
< wtindex
.cache_nr
; i
++) {
607 struct hashmap_entry dummy
;
608 const char *name
= wtindex
.cache
[i
]->name
;
611 add_path(&rdir
, rdir_len
, name
);
612 if (lstat(rdir
.buf
, &st
))
615 if ((symlinks
&& S_ISLNK(st
.st_mode
)) || !S_ISREG(st
.st_mode
))
618 if (!indices_loaded
) {
619 struct lock_file lock
= LOCK_INIT
;
621 strbuf_addf(&buf
, "%s/wtindex", tmpdir
.buf
);
622 if (hold_lock_file_for_update(&lock
, buf
.buf
, 0) < 0 ||
623 write_locked_index(&wtindex
, &lock
, COMMIT_LOCK
)) {
624 ret
= error("could not write %s", buf
.buf
);
627 changed_files(&wt_modified
, buf
.buf
, workdir
);
628 strbuf_setlen(&rdir
, rdir_len
);
629 changed_files(&tmp_modified
, buf
.buf
, rdir
.buf
);
630 add_path(&rdir
, rdir_len
, name
);
634 hashmap_entry_init(&dummy
, strhash(name
));
635 if (hashmap_get(&tmp_modified
, &dummy
, name
)) {
636 add_path(&wtdir
, wtdir_len
, name
);
637 if (hashmap_get(&wt_modified
, &dummy
, name
)) {
638 warning(_("both files modified: '%s' and '%s'."),
639 wtdir
.buf
, rdir
.buf
);
640 warning(_("working tree file has been left."));
643 } else if (unlink(wtdir
.buf
) ||
644 copy_file(wtdir
.buf
, rdir
.buf
, st
.st_mode
))
645 warning_errno(_("could not copy '%s' to '%s'"),
646 rdir
.buf
, wtdir
.buf
);
651 warning(_("temporary files exist in '%s'."), tmpdir
.buf
);
652 warning(_("you may want to cleanup or recover these."));
655 remove_dir_recursively(&tmpdir
, 0);
657 warning(_("failed: %d"), ret
);
666 strbuf_release(&ldir
);
667 strbuf_release(&rdir
);
668 strbuf_release(&wtdir
);
669 strbuf_release(&buf
);
670 strbuf_release(&tmpdir
);
672 return (ret
< 0) ? 1 : ret
;
675 static int run_file_diff(int prompt
, const char *prefix
,
676 struct child_process
*child
)
678 const char *env
[] = {
679 "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL
,
684 env
[2] = "GIT_DIFFTOOL_PROMPT=true";
686 env
[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
690 strvec_pushv(&child
->env
, env
);
692 return run_command(child
);
695 int cmd_difftool(int argc
, const char **argv
, const char *prefix
)
697 int use_gui_tool
= -1, dir_diff
= 0, prompt
= -1, symlinks
= 0,
698 tool_help
= 0, no_index
= 0;
699 static char *difftool_cmd
= NULL
, *extcmd
= NULL
;
700 struct option builtin_difftool_options
[] = {
701 OPT_BOOL('g', "gui", &use_gui_tool
,
702 N_("use `diff.guitool` instead of `diff.tool`")),
703 OPT_BOOL('d', "dir-diff", &dir_diff
,
704 N_("perform a full-directory diff")),
705 OPT_SET_INT_F('y', "no-prompt", &prompt
,
706 N_("do not prompt before launching a diff tool"),
708 OPT_SET_INT_F(0, "prompt", &prompt
, NULL
,
709 1, PARSE_OPT_NONEG
| PARSE_OPT_HIDDEN
),
710 OPT_BOOL(0, "symlinks", &symlinks
,
711 N_("use symlinks in dir-diff mode")),
712 OPT_STRING('t', "tool", &difftool_cmd
, N_("tool"),
713 N_("use the specified diff tool")),
714 OPT_BOOL(0, "tool-help", &tool_help
,
715 N_("print a list of diff tools that may be used with "
717 OPT_BOOL(0, "trust-exit-code", &trust_exit_code
,
718 N_("make 'git-difftool' exit when an invoked diff "
719 "tool returns a non-zero exit code")),
720 OPT_STRING('x', "extcmd", &extcmd
, N_("command"),
721 N_("specify a custom command for viewing diffs")),
722 OPT_BOOL(0, "no-index", &no_index
, N_("passed to `diff`")),
725 struct child_process child
= CHILD_PROCESS_INIT
;
727 git_config(difftool_config
, NULL
);
728 symlinks
= has_symlinks
;
730 argc
= parse_options(argc
, argv
, prefix
, builtin_difftool_options
,
731 builtin_difftool_usage
, PARSE_OPT_KEEP_UNKNOWN_OPT
|
732 PARSE_OPT_KEEP_DASHDASH
);
735 return print_tool_help();
737 if (!no_index
&& !startup_info
->have_repository
)
738 die(_("difftool requires worktree or --no-index"));
742 setenv(GIT_DIR_ENVIRONMENT
, absolute_path(get_git_dir()), 1);
743 setenv(GIT_WORK_TREE_ENVIRONMENT
, absolute_path(get_git_work_tree()), 1);
745 die(_("options '%s' and '%s' cannot be used together"), "--dir-diff", "--no-index");
747 die_for_incompatible_opt3(use_gui_tool
== 1, "--gui",
748 !!difftool_cmd
, "--tool",
749 !!extcmd
, "--extcmd");
752 * Explicitly specified GUI option is forwarded to git-mergetool--lib.sh;
753 * empty or unset means "use the difftool.guiDefault config or default to
756 if (use_gui_tool
== 1)
757 setenv("GIT_MERGETOOL_GUI", "true", 1);
758 else if (use_gui_tool
== 0)
759 setenv("GIT_MERGETOOL_GUI", "false", 1);
763 setenv("GIT_DIFF_TOOL", difftool_cmd
, 1);
765 die(_("no <tool> given for --tool=<tool>"));
770 setenv("GIT_DIFFTOOL_EXTCMD", extcmd
, 1);
772 die(_("no <cmd> given for --extcmd=<cmd>"));
775 setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
776 trust_exit_code
? "true" : "false", 1);
779 * In directory diff mode, 'git-difftool--helper' is called once
780 * to compare the a / b directories. In file diff mode, 'git diff'
781 * will invoke a separate instance of 'git-difftool--helper' for
782 * each file that changed.
784 strvec_push(&child
.args
, "diff");
786 strvec_push(&child
.args
, "--no-index");
788 strvec_pushl(&child
.args
, "--raw", "--no-abbrev", "-z", NULL
);
789 strvec_pushv(&child
.args
, argv
);
792 return run_dir_diff(extcmd
, symlinks
, prefix
, &child
);
793 return run_file_diff(prompt
, prefix
, &child
);