Merge branch 'jn/preformatted-doc-url' into maint
[git/git.git] / Documentation / git-format-patch.txt
1 git-format-patch(1)
2 ===================
3
4 NAME
5 ----
6 git-format-patch - Prepare patches for e-mail submission
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git format-patch' [-k] [(-o|--output-directory) <dir> | --stdout]
13 [--no-thread | --thread[=<style>]]
14 [(--attach|--inline)[=<boundary>] | --no-attach]
15 [-s | --signoff]
16 [--signature=<signature> | --no-signature]
17 [--signature-file=<file>]
18 [-n | --numbered | -N | --no-numbered]
19 [--start-number <n>] [--numbered-files]
20 [--in-reply-to=Message-Id] [--suffix=.<sfx>]
21 [--ignore-if-in-upstream]
22 [--subject-prefix=Subject-Prefix] [(--reroll-count|-v) <n>]
23 [--to=<email>] [--cc=<email>]
24 [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
25 [<common diff options>]
26 [ <since> | <revision range> ]
27
28 DESCRIPTION
29 -----------
30
31 Prepare each commit with its patch in
32 one file per commit, formatted to resemble UNIX mailbox format.
33 The output of this command is convenient for e-mail submission or
34 for use with 'git am'.
35
36 There are two ways to specify which commits to operate on.
37
38 1. A single commit, <since>, specifies that the commits leading
39 to the tip of the current branch that are not in the history
40 that leads to the <since> to be output.
41
42 2. Generic <revision range> expression (see "SPECIFYING
43 REVISIONS" section in linkgit:gitrevisions[7]) means the
44 commits in the specified range.
45
46 The first rule takes precedence in the case of a single <commit>. To
47 apply the second rule, i.e., format everything since the beginning of
48 history up until <commit>, use the '\--root' option: `git format-patch
49 --root <commit>`. If you want to format only <commit> itself, you
50 can do this with `git format-patch -1 <commit>`.
51
52 By default, each output file is numbered sequentially from 1, and uses the
53 first line of the commit message (massaged for pathname safety) as
54 the filename. With the `--numbered-files` option, the output file names
55 will only be numbers, without the first line of the commit appended.
56 The names of the output files are printed to standard
57 output, unless the `--stdout` option is specified.
58
59 If `-o` is specified, output files are created in <dir>. Otherwise
60 they are created in the current working directory. The default path
61 can be set with the `format.outputDirectory` configuration option.
62 The `-o` option takes precedence over `format.outputDirectory`.
63 To store patches in the current working directory even when
64 `format.outputDirectory` points elsewhere, use `-o .`.
65
66 By default, the subject of a single patch is "[PATCH] " followed by
67 the concatenation of lines from the commit message up to the first blank
68 line (see the DISCUSSION section of linkgit:git-commit[1]).
69
70 When multiple patches are output, the subject prefix will instead be
71 "[PATCH n/m] ". To force 1/1 to be added for a single patch, use `-n`.
72 To omit patch numbers from the subject, use `-N`.
73
74 If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
75 `References` headers to make the second and subsequent patch mails appear
76 as replies to the first mail; this also generates a `Message-Id` header to
77 reference.
78
79 OPTIONS
80 -------
81 :git-format-patch: 1
82 include::diff-options.txt[]
83
84 -<n>::
85 Prepare patches from the topmost <n> commits.
86
87 -o <dir>::
88 --output-directory <dir>::
89 Use <dir> to store the resulting files, instead of the
90 current working directory.
91
92 -n::
93 --numbered::
94 Name output in '[PATCH n/m]' format, even with a single patch.
95
96 -N::
97 --no-numbered::
98 Name output in '[PATCH]' format.
99
100 --start-number <n>::
101 Start numbering the patches at <n> instead of 1.
102
103 --numbered-files::
104 Output file names will be a simple number sequence
105 without the default first line of the commit appended.
106
107 -k::
108 --keep-subject::
109 Do not strip/add '[PATCH]' from the first line of the
110 commit log message.
111
112 -s::
113 --signoff::
114 Add `Signed-off-by:` line to the commit message, using
115 the committer identity of yourself.
116 See the signoff option in linkgit:git-commit[1] for more information.
117
118 --stdout::
119 Print all commits to the standard output in mbox format,
120 instead of creating a file for each one.
121
122 --attach[=<boundary>]::
123 Create multipart/mixed attachment, the first part of
124 which is the commit message and the patch itself in the
125 second part, with `Content-Disposition: attachment`.
126
127 --no-attach::
128 Disable the creation of an attachment, overriding the
129 configuration setting.
130
131 --inline[=<boundary>]::
132 Create multipart/mixed attachment, the first part of
133 which is the commit message and the patch itself in the
134 second part, with `Content-Disposition: inline`.
135
136 --thread[=<style>]::
137 --no-thread::
138 Controls addition of `In-Reply-To` and `References` headers to
139 make the second and subsequent mails appear as replies to the
140 first. Also controls generation of the `Message-Id` header to
141 reference.
142 +
143 The optional <style> argument can be either `shallow` or `deep`.
144 'shallow' threading makes every mail a reply to the head of the
145 series, where the head is chosen from the cover letter, the
146 `--in-reply-to`, and the first patch mail, in this order. 'deep'
147 threading makes every mail a reply to the previous one.
148 +
149 The default is `--no-thread`, unless the `format.thread` configuration
150 is set. If `--thread` is specified without a style, it defaults to the
151 style specified by `format.thread` if any, or else `shallow`.
152 +
153 Beware that the default for 'git send-email' is to thread emails
154 itself. If you want `git format-patch` to take care of threading, you
155 will want to ensure that threading is disabled for `git send-email`.
156
157 --in-reply-to=Message-Id::
158 Make the first mail (or all the mails with `--no-thread`) appear as a
159 reply to the given Message-Id, which avoids breaking threads to
160 provide a new patch series.
161
162 --ignore-if-in-upstream::
163 Do not include a patch that matches a commit in
164 <until>..<since>. This will examine all patches reachable
165 from <since> but not from <until> and compare them with the
166 patches being generated, and any patch that matches is
167 ignored.
168
169 --subject-prefix=<Subject-Prefix>::
170 Instead of the standard '[PATCH]' prefix in the subject
171 line, instead use '[<Subject-Prefix>]'. This
172 allows for useful naming of a patch series, and can be
173 combined with the `--numbered` option.
174
175 -v <n>::
176 --reroll-count=<n>::
177 Mark the series as the <n>-th iteration of the topic. The
178 output filenames have `v<n>` prepended to them, and the
179 subject prefix ("PATCH" by default, but configurable via the
180 `--subject-prefix` option) has ` v<n>` appended to it. E.g.
181 `--reroll-count=4` may produce `v4-0001-add-makefile.patch`
182 file that has "Subject: [PATCH v4 1/20] Add makefile" in it.
183
184 --to=<email>::
185 Add a `To:` header to the email headers. This is in addition
186 to any configured headers, and may be used multiple times.
187 The negated form `--no-to` discards all `To:` headers added so
188 far (from config or command line).
189
190 --cc=<email>::
191 Add a `Cc:` header to the email headers. This is in addition
192 to any configured headers, and may be used multiple times.
193 The negated form `--no-cc` discards all `Cc:` headers added so
194 far (from config or command line).
195
196 --from::
197 --from=<ident>::
198 Use `ident` in the `From:` header of each commit email. If the
199 author ident of the commit is not textually identical to the
200 provided `ident`, place a `From:` header in the body of the
201 message with the original author. If no `ident` is given, use
202 the committer ident.
203 +
204 Note that this option is only useful if you are actually sending the
205 emails and want to identify yourself as the sender, but retain the
206 original author (and `git am` will correctly pick up the in-body
207 header). Note also that `git send-email` already handles this
208 transformation for you, and this option should not be used if you are
209 feeding the result to `git send-email`.
210
211 --add-header=<header>::
212 Add an arbitrary header to the email headers. This is in addition
213 to any configured headers, and may be used multiple times.
214 For example, `--add-header="Organization: git-foo"`.
215 The negated form `--no-add-header` discards *all* (`To:`,
216 `Cc:`, and custom) headers added so far from config or command
217 line.
218
219 --[no-]cover-letter::
220 In addition to the patches, generate a cover letter file
221 containing the branch description, shortlog and the overall diffstat. You can
222 fill in a description in the file before sending it out.
223
224 --notes[=<ref>]::
225 Append the notes (see linkgit:git-notes[1]) for the commit
226 after the three-dash line.
227 +
228 The expected use case of this is to write supporting explanation for
229 the commit that does not belong to the commit log message proper,
230 and include it with the patch submission. While one can simply write
231 these explanations after `format-patch` has run but before sending,
232 keeping them as Git notes allows them to be maintained between versions
233 of the patch series (but see the discussion of the `notes.rewrite`
234 configuration options in linkgit:git-notes[1] to use this workflow).
235
236 --[no]-signature=<signature>::
237 Add a signature to each message produced. Per RFC 3676 the signature
238 is separated from the body by a line with '-- ' on it. If the
239 signature option is omitted the signature defaults to the Git version
240 number.
241
242 --signature-file=<file>::
243 Works just like --signature except the signature is read from a file.
244
245 --suffix=.<sfx>::
246 Instead of using `.patch` as the suffix for generated
247 filenames, use specified suffix. A common alternative is
248 `--suffix=.txt`. Leaving this empty will remove the `.patch`
249 suffix.
250 +
251 Note that the leading character does not have to be a dot; for example,
252 you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
253
254 -q::
255 --quiet::
256 Do not print the names of the generated files to standard output.
257
258 --no-binary::
259 Do not output contents of changes in binary files, instead
260 display a notice that those files changed. Patches generated
261 using this option cannot be applied properly, but they are
262 still useful for code review.
263
264 --zero-commit::
265 Output an all-zero hash in each patch's From header instead
266 of the hash of the commit.
267
268 --base=<commit>::
269 Record the base tree information to identify the state the
270 patch series applies to. See the BASE TREE INFORMATION section
271 below for details.
272
273 --root::
274 Treat the revision argument as a <revision range>, even if it
275 is just a single commit (that would normally be treated as a
276 <since>). Note that root commits included in the specified
277 range are always formatted as creation patches, independently
278 of this flag.
279
280 CONFIGURATION
281 -------------
282 You can specify extra mail header lines to be added to each message,
283 defaults for the subject prefix and file suffix, number patches when
284 outputting more than one patch, add "To" or "Cc:" headers, configure
285 attachments, and sign off patches with configuration variables.
286
287 ------------
288 [format]
289 headers = "Organization: git-foo\n"
290 subjectPrefix = CHANGE
291 suffix = .txt
292 numbered = auto
293 to = <email>
294 cc = <email>
295 attach [ = mime-boundary-string ]
296 signOff = true
297 coverletter = auto
298 ------------
299
300
301 DISCUSSION
302 ----------
303
304 The patch produced by 'git format-patch' is in UNIX mailbox format,
305 with a fixed "magic" time stamp to indicate that the file is output
306 from format-patch rather than a real mailbox, like so:
307
308 ------------
309 From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
310 From: Tony Luck <tony.luck@intel.com>
311 Date: Tue, 13 Jul 2010 11:42:54 -0700
312 Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
313 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
314 MIME-Version: 1.0
315 Content-Type: text/plain; charset=UTF-8
316 Content-Transfer-Encoding: 8bit
317
318 arch/arm config files were slimmed down using a python script
319 (See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
320
321 Do the same for ia64 so we can have sleek & trim looking
322 ...
323 ------------
324
325 Typically it will be placed in a MUA's drafts folder, edited to add
326 timely commentary that should not go in the changelog after the three
327 dashes, and then sent as a message whose body, in our example, starts
328 with "arch/arm config files were...". On the receiving end, readers
329 can save interesting patches in a UNIX mailbox and apply them with
330 linkgit:git-am[1].
331
332 When a patch is part of an ongoing discussion, the patch generated by
333 'git format-patch' can be tweaked to take advantage of the 'git am
334 --scissors' feature. After your response to the discussion comes a
335 line that consists solely of "`-- >8 --`" (scissors and perforation),
336 followed by the patch with unnecessary header fields removed:
337
338 ------------
339 ...
340 > So we should do such-and-such.
341
342 Makes sense to me. How about this patch?
343
344 -- >8 --
345 Subject: [IA64] Put ia64 config files on the Uwe Kleine-K├Ânig diet
346
347 arch/arm config files were slimmed down using a python script
348 ...
349 ------------
350
351 When sending a patch this way, most often you are sending your own
352 patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
353 should omit `From:` and `Date:` lines from the patch file. The patch
354 title is likely to be different from the subject of the discussion the
355 patch is in response to, so it is likely that you would want to keep
356 the Subject: line, like the example above.
357
358 Checking for patch corruption
359 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
360 Many mailers if not set up properly will corrupt whitespace. Here are
361 two common types of corruption:
362
363 * Empty context lines that do not have _any_ whitespace.
364
365 * Non-empty context lines that have one extra whitespace at the
366 beginning.
367
368 One way to test if your MUA is set up correctly is:
369
370 * Send the patch to yourself, exactly the way you would, except
371 with To: and Cc: lines that do not contain the list and
372 maintainer address.
373
374 * Save that patch to a file in UNIX mailbox format. Call it a.patch,
375 say.
376
377 * Apply it:
378
379 $ git fetch <project> master:test-apply
380 $ git checkout test-apply
381 $ git reset --hard
382 $ git am a.patch
383
384 If it does not apply correctly, there can be various reasons.
385
386 * The patch itself does not apply cleanly. That is _bad_ but
387 does not have much to do with your MUA. You might want to rebase
388 the patch with linkgit:git-rebase[1] before regenerating it in
389 this case.
390
391 * The MUA corrupted your patch; "am" would complain that
392 the patch does not apply. Look in the .git/rebase-apply/ subdirectory and
393 see what 'patch' file contains and check for the common
394 corruption patterns mentioned above.
395
396 * While at it, check the 'info' and 'final-commit' files as well.
397 If what is in 'final-commit' is not exactly what you would want to
398 see in the commit log message, it is very likely that the
399 receiver would end up hand editing the log message when applying
400 your patch. Things like "Hi, this is my first patch.\n" in the
401 patch e-mail should come after the three-dash line that signals
402 the end of the commit message.
403
404 MUA-SPECIFIC HINTS
405 ------------------
406 Here are some hints on how to successfully submit patches inline using
407 various mailers.
408
409 GMail
410 ~~~~~
411 GMail does not have any way to turn off line wrapping in the web
412 interface, so it will mangle any emails that you send. You can however
413 use "git send-email" and send your patches through the GMail SMTP server, or
414 use any IMAP email client to connect to the google IMAP server and forward
415 the emails through that.
416
417 For hints on using 'git send-email' to send your patches through the
418 GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
419
420 For hints on submission using the IMAP interface, see the EXAMPLE
421 section of linkgit:git-imap-send[1].
422
423 Thunderbird
424 ~~~~~~~~~~~
425 By default, Thunderbird will both wrap emails as well as flag
426 them as being 'format=flowed', both of which will make the
427 resulting email unusable by Git.
428
429 There are three different approaches: use an add-on to turn off line wraps,
430 configure Thunderbird to not mangle patches, or use
431 an external editor to keep Thunderbird from mangling the patches.
432
433 Approach #1 (add-on)
434 ^^^^^^^^^^^^^^^^^^^^
435
436 Install the Toggle Word Wrap add-on that is available from
437 https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
438 It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
439 that you can tick off. Now you can compose the message as you otherwise do
440 (cut + paste, 'git format-patch' | 'git imap-send', etc), but you have to
441 insert line breaks manually in any text that you type.
442
443 Approach #2 (configuration)
444 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
445 Three steps:
446
447 1. Configure your mail server composition as plain text:
448 Edit...Account Settings...Composition & Addressing,
449 uncheck "Compose Messages in HTML".
450
451 2. Configure your general composition window to not wrap.
452 +
453 In Thunderbird 2:
454 Edit..Preferences..Composition, wrap plain text messages at 0
455 +
456 In Thunderbird 3:
457 Edit..Preferences..Advanced..Config Editor. Search for
458 "mail.wrap_long_lines".
459 Toggle it to make sure it is set to `false`. Also, search for
460 "mailnews.wraplength" and set the value to 0.
461
462 3. Disable the use of format=flowed:
463 Edit..Preferences..Advanced..Config Editor. Search for
464 "mailnews.send_plaintext_flowed".
465 Toggle it to make sure it is set to `false`.
466
467 After that is done, you should be able to compose email as you
468 otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
469 and the patches will not be mangled.
470
471 Approach #3 (external editor)
472 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
473
474 The following Thunderbird extensions are needed:
475 AboutConfig from http://aboutconfig.mozdev.org/ and
476 External Editor from http://globs.org/articles.php?lng=en&pg=8
477
478 1. Prepare the patch as a text file using your method of choice.
479
480 2. Before opening a compose window, use Edit->Account Settings to
481 uncheck the "Compose messages in HTML format" setting in the
482 "Composition & Addressing" panel of the account to be used to
483 send the patch.
484
485 3. In the main Thunderbird window, 'before' you open the compose
486 window for the patch, use Tools->about:config to set the
487 following to the indicated values:
488 +
489 ----------
490 mailnews.send_plaintext_flowed => false
491 mailnews.wraplength => 0
492 ----------
493
494 4. Open a compose window and click the external editor icon.
495
496 5. In the external editor window, read in the patch file and exit
497 the editor normally.
498
499 Side note: it may be possible to do step 2 with
500 about:config and the following settings but no one's tried yet.
501
502 ----------
503 mail.html_compose => false
504 mail.identity.default.compose_html => false
505 mail.identity.id?.compose_html => false
506 ----------
507
508 There is a script in contrib/thunderbird-patch-inline which can help
509 you include patches with Thunderbird in an easy way. To use it, do the
510 steps above and then use the script as the external editor.
511
512 KMail
513 ~~~~~
514 This should help you to submit patches inline using KMail.
515
516 1. Prepare the patch as a text file.
517
518 2. Click on New Mail.
519
520 3. Go under "Options" in the Composer window and be sure that
521 "Word wrap" is not set.
522
523 4. Use Message -> Insert file... and insert the patch.
524
525 5. Back in the compose window: add whatever other text you wish to the
526 message, complete the addressing and subject fields, and press send.
527
528 BASE TREE INFORMATION
529 ---------------------
530
531 The base tree information block is used for maintainers or third party
532 testers to know the exact state the patch series applies to. It consists
533 of the 'base commit', which is a well-known commit that is part of the
534 stable part of the project history everybody else works off of, and zero
535 or more 'prerequisite patches', which are well-known patches in flight
536 that is not yet part of the 'base commit' that need to be applied on top
537 of 'base commit' in topological order before the patches can be applied.
538
539 The 'base commit' is shown as "base-commit: " followed by the 40-hex of
540 the commit object name. A 'prerequisite patch' is shown as
541 "prerequisite-patch-id: " followed by the 40-hex 'patch id', which can
542 be obtained by passing the patch through the `git patch-id --stable`
543 command.
544
545 Imagine that on top of the public commit P, you applied well-known
546 patches X, Y and Z from somebody else, and then built your three-patch
547 series A, B, C, the history would be like:
548
549 ................................................
550 ---P---X---Y---Z---A---B---C
551 ................................................
552
553 With `git format-patch --base=P -3 C` (or variants thereof, e.g. with
554 `--cover-letter` of using `Z..C` instead of `-3 C` to specify the
555 range), the base tree information block is shown at the end of the
556 first message the command outputs (either the first patch, or the
557 cover letter), like this:
558
559 ------------
560 base-commit: P
561 prerequisite-patch-id: X
562 prerequisite-patch-id: Y
563 prerequisite-patch-id: Z
564 ------------
565
566 For non-linear topology, such as
567
568 ................................................
569 ---P---X---A---M---C
570 \ /
571 Y---Z---B
572 ................................................
573
574 You can also use `git format-patch --base=P -3 C` to generate patches
575 for A, B and C, and the identifiers for P, X, Y, Z are appended at the
576 end of the first message.
577
578 If set `--base=auto` in cmdline, it will track base commit automatically,
579 the base commit will be the merge base of tip commit of the remote-tracking
580 branch and revision-range specified in cmdline.
581 For a local branch, you need to track a remote branch by `git branch
582 --set-upstream-to` before using this option.
583
584 EXAMPLES
585 --------
586
587 * Extract commits between revisions R1 and R2, and apply them on top of
588 the current branch using 'git am' to cherry-pick them:
589 +
590 ------------
591 $ git format-patch -k --stdout R1..R2 | git am -3 -k
592 ------------
593
594 * Extract all commits which are in the current branch but not in the
595 origin branch:
596 +
597 ------------
598 $ git format-patch origin
599 ------------
600 +
601 For each commit a separate file is created in the current directory.
602
603 * Extract all commits that lead to 'origin' since the inception of the
604 project:
605 +
606 ------------
607 $ git format-patch --root origin
608 ------------
609
610 * The same as the previous one:
611 +
612 ------------
613 $ git format-patch -M -B origin
614 ------------
615 +
616 Additionally, it detects and handles renames and complete rewrites
617 intelligently to produce a renaming patch. A renaming patch reduces
618 the amount of text output, and generally makes it easier to review.
619 Note that non-Git "patch" programs won't understand renaming patches, so
620 use it only when you know the recipient uses Git to apply your patch.
621
622 * Extract three topmost commits from the current branch and format them
623 as e-mailable patches:
624 +
625 ------------
626 $ git format-patch -3
627 ------------
628
629 SEE ALSO
630 --------
631 linkgit:git-am[1], linkgit:git-send-email[1]
632
633 GIT
634 ---
635 Part of the linkgit:git[1] suite