patch-ids: make commit_patch_id() a public helper function
[git/git.git] / Documentation / git-format-patch.txt
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1git-format-patch(1)
2===================
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3
4NAME
5----
7bd7f280 6git-format-patch - Prepare patches for e-mail submission
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7
8
9SYNOPSIS
10--------
353ce815 11[verse]
50710ce4 12'git format-patch' [-k] [(-o|--output-directory) <dir> | --stdout]
f693b7e9 13 [--no-thread | --thread[=<style>]]
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14 [(--attach|--inline)[=<boundary>] | --no-attach]
15 [-s | --signoff]
6622d9c7 16 [--signature=<signature> | --no-signature]
7022650f 17 [--signature-file=<file>]
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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]
7952ea66 22 [--subject-prefix=Subject-Prefix] [(--reroll-count|-v) <n>]
ae6c098f 23 [--to=<email>] [--cc=<email>]
2a4c2607 24 [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
50710ce4 25 [<common diff options>]
8a1d076e 26 [ <since> | <revision range> ]
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27
28DESCRIPTION
29-----------
2052d146 30
8a1d076e 31Prepare each commit with its patch in
2052d146 32one file per commit, formatted to resemble UNIX mailbox format.
2052d146 33The output of this command is convenient for e-mail submission or
0b444cdb 34for use with 'git am'.
35ef3a4c 35
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36There are two ways to specify which commits to operate on.
37
381. 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
422. Generic <revision range> expression (see "SPECIFYING
9d83e382 43 REVISIONS" section in linkgit:gitrevisions[7]) means the
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44 commits in the specified range.
45
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46The first rule takes precedence in the case of a single <commit>. To
47apply the second rule, i.e., format everything since the beginning of
dce5ef14 48history up until <commit>, use the '\--root' option: `git format-patch
6cf378f0 49--root <commit>`. If you want to format only <commit> itself, you
dce5ef14 50can do this with `git format-patch -1 <commit>`.
8a1d076e 51
e6ff0f42 52By default, each output file is numbered sequentially from 1, and uses the
2052d146 53first line of the commit message (massaged for pathname safety) as
dce5ef14 54the filename. With the `--numbered-files` option, the output file names
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55will only be numbers, without the first line of the commit appended.
56The names of the output files are printed to standard
dce5ef14 57output, unless the `--stdout` option is specified.
66f04f38 58
dce5ef14 59If `-o` is specified, output files are created in <dir>. Otherwise
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60they are created in the current working directory. The default path
61can be set with the 'format.outputDirectory' configuration option.
62The `-o` option takes precedence over `format.outputDirectory`.
63To store patches in the current working directory even when
64`format.outputDirectory` points elsewhere, use `-o .`.
35ef3a4c 65
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66By default, the subject of a single patch is "[PATCH] " followed by
67the concatenation of lines from the commit message up to the first blank
68line (see the DISCUSSION section of linkgit:git-commit[1]).
69
70When 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`.
72To omit patch numbers from the subject, use `-N`.
35ef3a4c 73
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74If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
75`References` headers to make the second and subsequent patch mails appear
76as replies to the first mail; this also generates a `Message-Id` header to
cc35de84 77reference.
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78
79OPTIONS
80-------
c1a95fa6 81:git-format-patch: 1
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82include::diff-options.txt[]
83
ed5f07a6 84-<n>::
2c642ed8 85 Prepare patches from the topmost <n> commits.
ed5f07a6 86
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87-o <dir>::
88--output-directory <dir>::
35ef3a4c 89 Use <dir> to store the resulting files, instead of the
efd02016 90 current working directory.
35ef3a4c 91
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92-n::
93--numbered::
a567fdcb 94 Name output in '[PATCH n/m]' format, even with a single patch.
35ef3a4c 95
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96-N::
97--no-numbered::
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98 Name output in '[PATCH]' format.
99
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100--start-number <n>::
101 Start numbering the patches at <n> instead of 1.
102
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103--numbered-files::
104 Output file names will be a simple number sequence
105 without the default first line of the commit appended.
e6ff0f42 106
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107-k::
108--keep-subject::
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109 Do not strip/add '[PATCH]' from the first line of the
110 commit log message.
111
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112-s::
113--signoff::
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114 Add `Signed-off-by:` line to the commit message, using
115 the committer identity of yourself.
b2c150d3 116 See the signoff option in linkgit:git-commit[1] for more information.
6f855371 117
54ba6013 118--stdout::
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119 Print all commits to the standard output in mbox format,
120 instead of creating a file for each one.
7fc9d69f 121
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122--attach[=<boundary>]::
123 Create multipart/mixed attachment, the first part of
124 which is the commit message and the patch itself in the
dce5ef14 125 second part, with `Content-Disposition: attachment`.
c112f689 126
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127--no-attach::
128 Disable the creation of an attachment, overriding the
129 configuration setting.
130
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131--inline[=<boundary>]::
132 Create multipart/mixed attachment, the first part of
133 which is the commit message and the patch itself in the
dce5ef14 134 second part, with `Content-Disposition: inline`.
a15a44ef 135
30984ed2 136--thread[=<style>]::
f693b7e9 137--no-thread::
dce5ef14 138 Controls addition of `In-Reply-To` and `References` headers to
f693b7e9 139 make the second and subsequent mails appear as replies to the
dce5ef14 140 first. Also controls generation of the `Message-Id` header to
f693b7e9 141 reference.
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142+
143The optional <style> argument can be either `shallow` or `deep`.
fd1ff306 144'shallow' threading makes every mail a reply to the head of the
30984ed2 145series, where the head is chosen from the cover letter, the
6cf378f0 146`--in-reply-to`, and the first patch mail, in this order. 'deep'
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147threading makes every mail a reply to the previous one.
148+
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149The default is `--no-thread`, unless the 'format.thread' configuration
150is set. If `--thread` is specified without a style, it defaults to the
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151style specified by 'format.thread' if any, or else `shallow`.
152+
153Beware that the default for 'git send-email' is to thread emails
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154itself. If you want `git format-patch` to take care of threading, you
155will want to ensure that threading is disabled for `git send-email`.
28ffb898 156
da56645d 157--in-reply-to=Message-Id::
dce5ef14 158 Make the first mail (or all the mails with `--no-thread`) appear as a
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159 reply to the given Message-Id, which avoids breaking threads to
160 provide a new patch series.
161
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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
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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
dce5ef14 173 combined with the `--numbered` option.
2d9e4a47 174
7952ea66 175-v <n>::
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176--reroll-count=<n>::
177 Mark the series as the <n>-th iteration of the topic. The
d614f075 178 output filenames have `v<n>` prepended to them, and the
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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
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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.
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187 The negated form `--no-to` discards all `To:` headers added so
188 far (from config or command line).
ae6c098f 189
736cc67d 190--cc=<email>::
dce5ef14 191 Add a `Cc:` header to the email headers. This is in addition
736cc67d 192 to any configured headers, and may be used multiple times.
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193 The negated form `--no-cc` discards all `Cc:` headers added so
194 far (from config or command line).
736cc67d 195
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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+
204Note that this option is only useful if you are actually sending the
205emails and want to identify yourself as the sender, but retain the
206original author (and `git am` will correctly pick up the in-body
207header). Note also that `git send-email` already handles this
208transformation for you, and this option should not be used if you are
209feeding the result to `git send-email`.
210
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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.
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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.
d7d9c2d0 218
2a4c2607 219--[no-]cover-letter::
f4912391 220 In addition to the patches, generate a cover letter file
561d2b79 221 containing the branch description, shortlog and the overall diffstat. You can
f4912391 222 fill in a description in the file before sending it out.
a5a27c79 223
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224--notes[=<ref>]::
225 Append the notes (see linkgit:git-notes[1]) for the commit
226 after the three-dash line.
227+
228The expected use case of this is to write supporting explanation for
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229the commit that does not belong to the commit log message proper,
230and include it with the patch submission. While one can simply write
231these explanations after `format-patch` has run but before sending,
2de9b711 232keeping them as Git notes allows them to be maintained between versions
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233of the patch series (but see the discussion of the `notes.rewrite`
234configuration options in linkgit:git-notes[1] to use this workflow).
e422c0cf 235
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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
2de9b711 239 signature option is omitted the signature defaults to the Git version
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240 number.
241
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242--signature-file=<file>::
243 Works just like --signature except the signature is read from a file.
244
03eeaeae 245--suffix=.<sfx>::
917a8f89 246 Instead of using `.patch` as the suffix for generated
02783075 247 filenames, use specified suffix. A common alternative is
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248 `--suffix=.txt`. Leaving this empty will remove the `.patch`
249 suffix.
03eeaeae 250+
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251Note that the leading character does not have to be a dot; for example,
252you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
03eeaeae 253
b7df098c 254-q::
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255--quiet::
256 Do not print the names of the generated files to standard output.
257
37c22a4b 258--no-binary::
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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.
37c22a4b 263
3a30aa17 264--zero-commit::
265 Output an all-zero hash in each patch's From header instead
266 of the hash of the commit.
267
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268--root::
269 Treat the revision argument as a <revision range>, even if it
270 is just a single commit (that would normally be treated as a
271 <since>). Note that root commits included in the specified
272 range are always formatted as creation patches, independently
273 of this flag.
274
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275CONFIGURATION
276-------------
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277You can specify extra mail header lines to be added to each message,
278defaults for the subject prefix and file suffix, number patches when
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279outputting more than one patch, add "To" or "Cc:" headers, configure
280attachments, and sign off patches with configuration variables.
96ce6d26 281
917a8f89 282------------
96ce6d26 283[format]
7f9d77f2 284 headers = "Organization: git-foo\n"
da0005b8 285 subjectPrefix = CHANGE
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286 suffix = .txt
287 numbered = auto
ae6c098f 288 to = <email>
fe8928e6 289 cc = <email>
0db5260b 290 attach [ = mime-boundary-string ]
da0005b8 291 signOff = true
2a4c2607 292 coverletter = auto
917a8f89 293------------
03eeaeae 294
96ce6d26 295
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296DISCUSSION
297----------
298
299The patch produced by 'git format-patch' is in UNIX mailbox format,
300with a fixed "magic" time stamp to indicate that the file is output
301from format-patch rather than a real mailbox, like so:
302
303------------
304From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
305From: Tony Luck <tony.luck@intel.com>
306Date: Tue, 13 Jul 2010 11:42:54 -0700
307Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
308 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
309MIME-Version: 1.0
310Content-Type: text/plain; charset=UTF-8
311Content-Transfer-Encoding: 8bit
312
313arch/arm config files were slimmed down using a python script
314(See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
315
316Do the same for ia64 so we can have sleek & trim looking
317...
318------------
319
320Typically it will be placed in a MUA's drafts folder, edited to add
321timely commentary that should not go in the changelog after the three
322dashes, and then sent as a message whose body, in our example, starts
323with "arch/arm config files were...". On the receiving end, readers
324can save interesting patches in a UNIX mailbox and apply them with
325linkgit:git-am[1].
326
327When a patch is part of an ongoing discussion, the patch generated by
328'git format-patch' can be tweaked to take advantage of the 'git am
329--scissors' feature. After your response to the discussion comes a
330line that consists solely of "`-- >8 --`" (scissors and perforation),
331followed by the patch with unnecessary header fields removed:
332
333------------
334...
335> So we should do such-and-such.
336
337Makes sense to me. How about this patch?
338
339-- >8 --
340Subject: [IA64] Put ia64 config files on the Uwe Kleine-König diet
341
342arch/arm config files were slimmed down using a python script
343...
344------------
345
346When sending a patch this way, most often you are sending your own
347patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
348should omit `From:` and `Date:` lines from the patch file. The patch
349title is likely to be different from the subject of the discussion the
350patch is in response to, so it is likely that you would want to keep
351the Subject: line, like the example above.
352
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353Checking for patch corruption
354~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
355Many mailers if not set up properly will corrupt whitespace. Here are
356two common types of corruption:
357
358* Empty context lines that do not have _any_ whitespace.
359
360* Non-empty context lines that have one extra whitespace at the
361 beginning.
362
363One way to test if your MUA is set up correctly is:
364
365* Send the patch to yourself, exactly the way you would, except
366 with To: and Cc: lines that do not contain the list and
367 maintainer address.
368
369* Save that patch to a file in UNIX mailbox format. Call it a.patch,
370 say.
371
372* Apply it:
373
374 $ git fetch <project> master:test-apply
375 $ git checkout test-apply
376 $ git reset --hard
377 $ git am a.patch
378
379If it does not apply correctly, there can be various reasons.
380
381* The patch itself does not apply cleanly. That is _bad_ but
382 does not have much to do with your MUA. You might want to rebase
383 the patch with linkgit:git-rebase[1] before regenerating it in
384 this case.
385
386* The MUA corrupted your patch; "am" would complain that
387 the patch does not apply. Look in the .git/rebase-apply/ subdirectory and
388 see what 'patch' file contains and check for the common
389 corruption patterns mentioned above.
390
391* While at it, check the 'info' and 'final-commit' files as well.
392 If what is in 'final-commit' is not exactly what you would want to
393 see in the commit log message, it is very likely that the
394 receiver would end up hand editing the log message when applying
395 your patch. Things like "Hi, this is my first patch.\n" in the
396 patch e-mail should come after the three-dash line that signals
397 the end of the commit message.
398
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399MUA-SPECIFIC HINTS
400------------------
401Here are some hints on how to successfully submit patches inline using
402various mailers.
403
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404GMail
405~~~~~
406GMail does not have any way to turn off line wrapping in the web
407interface, so it will mangle any emails that you send. You can however
408use "git send-email" and send your patches through the GMail SMTP server, or
409use any IMAP email client to connect to the google IMAP server and forward
410the emails through that.
411
412For hints on using 'git send-email' to send your patches through the
413GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
414
415For hints on submission using the IMAP interface, see the EXAMPLE
416section of linkgit:git-imap-send[1].
417
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418Thunderbird
419~~~~~~~~~~~
420By default, Thunderbird will both wrap emails as well as flag
421them as being 'format=flowed', both of which will make the
2de9b711 422resulting email unusable by Git.
dc53151f 423
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424There are three different approaches: use an add-on to turn off line wraps,
425configure Thunderbird to not mangle patches, or use
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426an external editor to keep Thunderbird from mangling the patches.
427
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428Approach #1 (add-on)
429^^^^^^^^^^^^^^^^^^^^
430
431Install the Toggle Word Wrap add-on that is available from
432https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
433It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
434that you can tick off. Now you can compose the message as you otherwise do
435(cut + paste, 'git format-patch' | 'git imap-send', etc), but you have to
436insert line breaks manually in any text that you type.
437
438Approach #2 (configuration)
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439^^^^^^^^^^^^^^^^^^^^^^^^^^^
440Three steps:
441
4421. Configure your mail server composition as plain text:
443 Edit...Account Settings...Composition & Addressing,
444 uncheck "Compose Messages in HTML".
445
4462. Configure your general composition window to not wrap.
447+
448In Thunderbird 2:
449Edit..Preferences..Composition, wrap plain text messages at 0
450+
451In Thunderbird 3:
452Edit..Preferences..Advanced..Config Editor. Search for
453"mail.wrap_long_lines".
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454Toggle it to make sure it is set to `false`. Also, search for
455"mailnews.wraplength" and set the value to 0.
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456
4573. Disable the use of format=flowed:
458Edit..Preferences..Advanced..Config Editor. Search for
459"mailnews.send_plaintext_flowed".
460Toggle it to make sure it is set to `false`.
461
462After that is done, you should be able to compose email as you
463otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
464and the patches will not be mangled.
465
b8959605 466Approach #3 (external editor)
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467^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
468
469The following Thunderbird extensions are needed:
470AboutConfig from http://aboutconfig.mozdev.org/ and
471External Editor from http://globs.org/articles.php?lng=en&pg=8
472
4731. Prepare the patch as a text file using your method of choice.
474
4752. Before opening a compose window, use Edit->Account Settings to
476 uncheck the "Compose messages in HTML format" setting in the
477 "Composition & Addressing" panel of the account to be used to
478 send the patch.
479
4803. In the main Thunderbird window, 'before' you open the compose
481 window for the patch, use Tools->about:config to set the
482 following to the indicated values:
483+
484----------
485 mailnews.send_plaintext_flowed => false
486 mailnews.wraplength => 0
487----------
488
4894. Open a compose window and click the external editor icon.
490
4915. In the external editor window, read in the patch file and exit
492 the editor normally.
493
494Side note: it may be possible to do step 2 with
495about:config and the following settings but no one's tried yet.
496
497----------
498 mail.html_compose => false
499 mail.identity.default.compose_html => false
500 mail.identity.id?.compose_html => false
501----------
502
503There is a script in contrib/thunderbird-patch-inline which can help
504you include patches with Thunderbird in an easy way. To use it, do the
505steps above and then use the script as the external editor.
506
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507KMail
508~~~~~
509This should help you to submit patches inline using KMail.
510
5111. Prepare the patch as a text file.
512
5132. Click on New Mail.
514
5153. Go under "Options" in the Composer window and be sure that
516 "Word wrap" is not set.
517
5184. Use Message -> Insert file... and insert the patch.
519
5205. Back in the compose window: add whatever other text you wish to the
521 message, complete the addressing and subject fields, and press send.
522
e0d48279 523
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524EXAMPLES
525--------
526
921177f5 527* Extract commits between revisions R1 and R2, and apply them on top of
0b444cdb 528the current branch using 'git am' to cherry-pick them:
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529+
530------------
467c0197 531$ git format-patch -k --stdout R1..R2 | git am -3 -k
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532------------
533
534* Extract all commits which are in the current branch but not in the
535origin branch:
536+
537------------
538$ git format-patch origin
539------------
540+
541For each commit a separate file is created in the current directory.
542
543* Extract all commits that lead to 'origin' since the inception of the
544project:
545+
546------------
9c67c757 547$ git format-patch --root origin
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548------------
549
550* The same as the previous one:
551+
552------------
553$ git format-patch -M -B origin
554------------
555+
556Additionally, it detects and handles renames and complete rewrites
557intelligently to produce a renaming patch. A renaming patch reduces
50710ce4 558the amount of text output, and generally makes it easier to review.
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559Note that non-Git "patch" programs won't understand renaming patches, so
560use it only when you know the recipient uses Git to apply your patch.
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561
562* Extract three topmost commits from the current branch and format them
563as e-mailable patches:
564+
565------------
566$ git format-patch -3
567------------
28ffb898 568
56ae8df5 569SEE ALSO
28ffb898 570--------
5162e697 571linkgit:git-am[1], linkgit:git-send-email[1]
28ffb898 572
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573GIT
574---
9e1f0a85 575Part of the linkgit:git[1] suite