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