Git 1.8.0.3
[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 [-n | --numbered | -N | --no-numbered]
18 [--start-number <n>] [--numbered-files]
19 [--in-reply-to=Message-Id] [--suffix=.<sfx>]
20 [--ignore-if-in-upstream]
21 [--subject-prefix=Subject-Prefix]
22 [--to=<email>] [--cc=<email>]
23 [--cover-letter] [--quiet]
24 [<common diff options>]
25 [ <since> | <revision range> ]
26
27 DESCRIPTION
28 -----------
29
30 Prepare each commit with its patch in
31 one file per commit, formatted to resemble UNIX mailbox format.
32 The output of this command is convenient for e-mail submission or
33 for use with 'git am'.
34
35 There are two ways to specify which commits to operate on.
36
37 1. A single commit, <since>, specifies that the commits leading
38 to the tip of the current branch that are not in the history
39 that leads to the <since> to be output.
40
41 2. Generic <revision range> expression (see "SPECIFYING
42 REVISIONS" section in linkgit:gitrevisions[7]) means the
43 commits in the specified range.
44
45 The first rule takes precedence in the case of a single <commit>. To
46 apply the second rule, i.e., format everything since the beginning of
47 history up until <commit>, use the '\--root' option: `git format-patch
48 --root <commit>`. If you want to format only <commit> itself, you
49 can do this with `git format-patch -1 <commit>`.
50
51 By default, each output file is numbered sequentially from 1, and uses the
52 first line of the commit message (massaged for pathname safety) as
53 the filename. With the `--numbered-files` option, the output file names
54 will only be numbers, without the first line of the commit appended.
55 The names of the output files are printed to standard
56 output, unless the `--stdout` option is specified.
57
58 If `-o` is specified, output files are created in <dir>. Otherwise
59 they are created in the current working directory.
60
61 By default, the subject of a single patch is "[PATCH] " followed by
62 the concatenation of lines from the commit message up to the first blank
63 line (see the DISCUSSION section of linkgit:git-commit[1]).
64
65 When multiple patches are output, the subject prefix will instead be
66 "[PATCH n/m] ". To force 1/1 to be added for a single patch, use `-n`.
67 To omit patch numbers from the subject, use `-N`.
68
69 If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
70 `References` headers to make the second and subsequent patch mails appear
71 as replies to the first mail; this also generates a `Message-Id` header to
72 reference.
73
74 OPTIONS
75 -------
76 :git-format-patch: 1
77 include::diff-options.txt[]
78
79 -<n>::
80 Prepare patches from the topmost <n> commits.
81
82 -o <dir>::
83 --output-directory <dir>::
84 Use <dir> to store the resulting files, instead of the
85 current working directory.
86
87 -n::
88 --numbered::
89 Name output in '[PATCH n/m]' format, even with a single patch.
90
91 -N::
92 --no-numbered::
93 Name output in '[PATCH]' format.
94
95 --start-number <n>::
96 Start numbering the patches at <n> instead of 1.
97
98 --numbered-files::
99 Output file names will be a simple number sequence
100 without the default first line of the commit appended.
101
102 -k::
103 --keep-subject::
104 Do not strip/add '[PATCH]' from the first line of the
105 commit log message.
106
107 -s::
108 --signoff::
109 Add `Signed-off-by:` line to the commit message, using
110 the committer identity of yourself.
111
112 --stdout::
113 Print all commits to the standard output in mbox format,
114 instead of creating a file for each one.
115
116 --attach[=<boundary>]::
117 Create multipart/mixed attachment, the first part of
118 which is the commit message and the patch itself in the
119 second part, with `Content-Disposition: attachment`.
120
121 --no-attach::
122 Disable the creation of an attachment, overriding the
123 configuration setting.
124
125 --inline[=<boundary>]::
126 Create multipart/mixed attachment, the first part of
127 which is the commit message and the patch itself in the
128 second part, with `Content-Disposition: inline`.
129
130 --thread[=<style>]::
131 --no-thread::
132 Controls addition of `In-Reply-To` and `References` headers to
133 make the second and subsequent mails appear as replies to the
134 first. Also controls generation of the `Message-Id` header to
135 reference.
136 +
137 The optional <style> argument can be either `shallow` or `deep`.
138 'shallow' threading makes every mail a reply to the head of the
139 series, where the head is chosen from the cover letter, the
140 `--in-reply-to`, and the first patch mail, in this order. 'deep'
141 threading makes every mail a reply to the previous one.
142 +
143 The default is `--no-thread`, unless the 'format.thread' configuration
144 is set. If `--thread` is specified without a style, it defaults to the
145 style specified by 'format.thread' if any, or else `shallow`.
146 +
147 Beware that the default for 'git send-email' is to thread emails
148 itself. If you want `git format-patch` to take care of threading, you
149 will want to ensure that threading is disabled for `git send-email`.
150
151 --in-reply-to=Message-Id::
152 Make the first mail (or all the mails with `--no-thread`) appear as a
153 reply to the given Message-Id, which avoids breaking threads to
154 provide a new patch series.
155
156 --ignore-if-in-upstream::
157 Do not include a patch that matches a commit in
158 <until>..<since>. This will examine all patches reachable
159 from <since> but not from <until> and compare them with the
160 patches being generated, and any patch that matches is
161 ignored.
162
163 --subject-prefix=<Subject-Prefix>::
164 Instead of the standard '[PATCH]' prefix in the subject
165 line, instead use '[<Subject-Prefix>]'. This
166 allows for useful naming of a patch series, and can be
167 combined with the `--numbered` option.
168
169 --to=<email>::
170 Add a `To:` header to the email headers. This is in addition
171 to any configured headers, and may be used multiple times.
172 The negated form `--no-to` discards all `To:` headers added so
173 far (from config or command line).
174
175 --cc=<email>::
176 Add a `Cc:` header to the email headers. This is in addition
177 to any configured headers, and may be used multiple times.
178 The negated form `--no-cc` discards all `Cc:` headers added so
179 far (from config or command line).
180
181 --add-header=<header>::
182 Add an arbitrary header to the email headers. This is in addition
183 to any configured headers, and may be used multiple times.
184 For example, `--add-header="Organization: git-foo"`.
185 The negated form `--no-add-header` discards *all* (`To:`,
186 `Cc:`, and custom) headers added so far from config or command
187 line.
188
189 --cover-letter::
190 In addition to the patches, generate a cover letter file
191 containing the shortlog and the overall diffstat. You can
192 fill in a description in the file before sending it out.
193
194 --[no]-signature=<signature>::
195 Add a signature to each message produced. Per RFC 3676 the signature
196 is separated from the body by a line with '-- ' on it. If the
197 signature option is omitted the signature defaults to the git version
198 number.
199
200 --suffix=.<sfx>::
201 Instead of using `.patch` as the suffix for generated
202 filenames, use specified suffix. A common alternative is
203 `--suffix=.txt`. Leaving this empty will remove the `.patch`
204 suffix.
205 +
206 Note that the leading character does not have to be a dot; for example,
207 you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
208
209 --quiet::
210 Do not print the names of the generated files to standard output.
211
212 --no-binary::
213 Do not output contents of changes in binary files, instead
214 display a notice that those files changed. Patches generated
215 using this option cannot be applied properly, but they are
216 still useful for code review.
217
218 --root::
219 Treat the revision argument as a <revision range>, even if it
220 is just a single commit (that would normally be treated as a
221 <since>). Note that root commits included in the specified
222 range are always formatted as creation patches, independently
223 of this flag.
224
225 CONFIGURATION
226 -------------
227 You can specify extra mail header lines to be added to each message,
228 defaults for the subject prefix and file suffix, number patches when
229 outputting more than one patch, add "To" or "Cc:" headers, configure
230 attachments, and sign off patches with configuration variables.
231
232 ------------
233 [format]
234 headers = "Organization: git-foo\n"
235 subjectprefix = CHANGE
236 suffix = .txt
237 numbered = auto
238 to = <email>
239 cc = <email>
240 attach [ = mime-boundary-string ]
241 signoff = true
242 ------------
243
244
245 DISCUSSION
246 ----------
247
248 The patch produced by 'git format-patch' is in UNIX mailbox format,
249 with a fixed "magic" time stamp to indicate that the file is output
250 from format-patch rather than a real mailbox, like so:
251
252 ------------
253 From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
254 From: Tony Luck <tony.luck@intel.com>
255 Date: Tue, 13 Jul 2010 11:42:54 -0700
256 Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
257 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
258 MIME-Version: 1.0
259 Content-Type: text/plain; charset=UTF-8
260 Content-Transfer-Encoding: 8bit
261
262 arch/arm config files were slimmed down using a python script
263 (See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
264
265 Do the same for ia64 so we can have sleek & trim looking
266 ...
267 ------------
268
269 Typically it will be placed in a MUA's drafts folder, edited to add
270 timely commentary that should not go in the changelog after the three
271 dashes, and then sent as a message whose body, in our example, starts
272 with "arch/arm config files were...". On the receiving end, readers
273 can save interesting patches in a UNIX mailbox and apply them with
274 linkgit:git-am[1].
275
276 When a patch is part of an ongoing discussion, the patch generated by
277 'git format-patch' can be tweaked to take advantage of the 'git am
278 --scissors' feature. After your response to the discussion comes a
279 line that consists solely of "`-- >8 --`" (scissors and perforation),
280 followed by the patch with unnecessary header fields removed:
281
282 ------------
283 ...
284 > So we should do such-and-such.
285
286 Makes sense to me. How about this patch?
287
288 -- >8 --
289 Subject: [IA64] Put ia64 config files on the Uwe Kleine-K├Ânig diet
290
291 arch/arm config files were slimmed down using a python script
292 ...
293 ------------
294
295 When sending a patch this way, most often you are sending your own
296 patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
297 should omit `From:` and `Date:` lines from the patch file. The patch
298 title is likely to be different from the subject of the discussion the
299 patch is in response to, so it is likely that you would want to keep
300 the Subject: line, like the example above.
301
302 Checking for patch corruption
303 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
304 Many mailers if not set up properly will corrupt whitespace. Here are
305 two common types of corruption:
306
307 * Empty context lines that do not have _any_ whitespace.
308
309 * Non-empty context lines that have one extra whitespace at the
310 beginning.
311
312 One way to test if your MUA is set up correctly is:
313
314 * Send the patch to yourself, exactly the way you would, except
315 with To: and Cc: lines that do not contain the list and
316 maintainer address.
317
318 * Save that patch to a file in UNIX mailbox format. Call it a.patch,
319 say.
320
321 * Apply it:
322
323 $ git fetch <project> master:test-apply
324 $ git checkout test-apply
325 $ git reset --hard
326 $ git am a.patch
327
328 If it does not apply correctly, there can be various reasons.
329
330 * The patch itself does not apply cleanly. That is _bad_ but
331 does not have much to do with your MUA. You might want to rebase
332 the patch with linkgit:git-rebase[1] before regenerating it in
333 this case.
334
335 * The MUA corrupted your patch; "am" would complain that
336 the patch does not apply. Look in the .git/rebase-apply/ subdirectory and
337 see what 'patch' file contains and check for the common
338 corruption patterns mentioned above.
339
340 * While at it, check the 'info' and 'final-commit' files as well.
341 If what is in 'final-commit' is not exactly what you would want to
342 see in the commit log message, it is very likely that the
343 receiver would end up hand editing the log message when applying
344 your patch. Things like "Hi, this is my first patch.\n" in the
345 patch e-mail should come after the three-dash line that signals
346 the end of the commit message.
347
348 MUA-SPECIFIC HINTS
349 ------------------
350 Here are some hints on how to successfully submit patches inline using
351 various mailers.
352
353 GMail
354 ~~~~~
355 GMail does not have any way to turn off line wrapping in the web
356 interface, so it will mangle any emails that you send. You can however
357 use "git send-email" and send your patches through the GMail SMTP server, or
358 use any IMAP email client to connect to the google IMAP server and forward
359 the emails through that.
360
361 For hints on using 'git send-email' to send your patches through the
362 GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
363
364 For hints on submission using the IMAP interface, see the EXAMPLE
365 section of linkgit:git-imap-send[1].
366
367 Thunderbird
368 ~~~~~~~~~~~
369 By default, Thunderbird will both wrap emails as well as flag
370 them as being 'format=flowed', both of which will make the
371 resulting email unusable by git.
372
373 There are three different approaches: use an add-on to turn off line wraps,
374 configure Thunderbird to not mangle patches, or use
375 an external editor to keep Thunderbird from mangling the patches.
376
377 Approach #1 (add-on)
378 ^^^^^^^^^^^^^^^^^^^^
379
380 Install the Toggle Word Wrap add-on that is available from
381 https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
382 It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
383 that you can tick off. Now you can compose the message as you otherwise do
384 (cut + paste, 'git format-patch' | 'git imap-send', etc), but you have to
385 insert line breaks manually in any text that you type.
386
387 Approach #2 (configuration)
388 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
389 Three steps:
390
391 1. Configure your mail server composition as plain text:
392 Edit...Account Settings...Composition & Addressing,
393 uncheck "Compose Messages in HTML".
394
395 2. Configure your general composition window to not wrap.
396 +
397 In Thunderbird 2:
398 Edit..Preferences..Composition, wrap plain text messages at 0
399 +
400 In Thunderbird 3:
401 Edit..Preferences..Advanced..Config Editor. Search for
402 "mail.wrap_long_lines".
403 Toggle it to make sure it is set to `false`.
404
405 3. Disable the use of format=flowed:
406 Edit..Preferences..Advanced..Config Editor. Search for
407 "mailnews.send_plaintext_flowed".
408 Toggle it to make sure it is set to `false`.
409
410 After that is done, you should be able to compose email as you
411 otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
412 and the patches will not be mangled.
413
414 Approach #3 (external editor)
415 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
416
417 The following Thunderbird extensions are needed:
418 AboutConfig from http://aboutconfig.mozdev.org/ and
419 External Editor from http://globs.org/articles.php?lng=en&pg=8
420
421 1. Prepare the patch as a text file using your method of choice.
422
423 2. Before opening a compose window, use Edit->Account Settings to
424 uncheck the "Compose messages in HTML format" setting in the
425 "Composition & Addressing" panel of the account to be used to
426 send the patch.
427
428 3. In the main Thunderbird window, 'before' you open the compose
429 window for the patch, use Tools->about:config to set the
430 following to the indicated values:
431 +
432 ----------
433 mailnews.send_plaintext_flowed => false
434 mailnews.wraplength => 0
435 ----------
436
437 4. Open a compose window and click the external editor icon.
438
439 5. In the external editor window, read in the patch file and exit
440 the editor normally.
441
442 Side note: it may be possible to do step 2 with
443 about:config and the following settings but no one's tried yet.
444
445 ----------
446 mail.html_compose => false
447 mail.identity.default.compose_html => false
448 mail.identity.id?.compose_html => false
449 ----------
450
451 There is a script in contrib/thunderbird-patch-inline which can help
452 you include patches with Thunderbird in an easy way. To use it, do the
453 steps above and then use the script as the external editor.
454
455 KMail
456 ~~~~~
457 This should help you to submit patches inline using KMail.
458
459 1. Prepare the patch as a text file.
460
461 2. Click on New Mail.
462
463 3. Go under "Options" in the Composer window and be sure that
464 "Word wrap" is not set.
465
466 4. Use Message -> Insert file... and insert the patch.
467
468 5. Back in the compose window: add whatever other text you wish to the
469 message, complete the addressing and subject fields, and press send.
470
471
472 EXAMPLES
473 --------
474
475 * Extract commits between revisions R1 and R2, and apply them on top of
476 the current branch using 'git am' to cherry-pick them:
477 +
478 ------------
479 $ git format-patch -k --stdout R1..R2 | git am -3 -k
480 ------------
481
482 * Extract all commits which are in the current branch but not in the
483 origin branch:
484 +
485 ------------
486 $ git format-patch origin
487 ------------
488 +
489 For each commit a separate file is created in the current directory.
490
491 * Extract all commits that lead to 'origin' since the inception of the
492 project:
493 +
494 ------------
495 $ git format-patch --root origin
496 ------------
497
498 * The same as the previous one:
499 +
500 ------------
501 $ git format-patch -M -B origin
502 ------------
503 +
504 Additionally, it detects and handles renames and complete rewrites
505 intelligently to produce a renaming patch. A renaming patch reduces
506 the amount of text output, and generally makes it easier to review.
507 Note that non-git "patch" programs won't understand renaming patches, so
508 use it only when you know the recipient uses git to apply your patch.
509
510 * Extract three topmost commits from the current branch and format them
511 as e-mailable patches:
512 +
513 ------------
514 $ git format-patch -3
515 ------------
516
517 SEE ALSO
518 --------
519 linkgit:git-am[1], linkgit:git-send-email[1]
520
521 GIT
522 ---
523 Part of the linkgit:git[1] suite