Documentation / git-format-patch.txton commit git(1): remove a defunct link to "list of authors" (ac046c0)
   1git-format-patch(1)
   2===================
   3
   4NAME
   5----
   6git-format-patch - Prepare patches for e-mail submission
   7
   8
   9SYNOPSIS
  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
  27DESCRIPTION
  28-----------
  29
  30Prepare each commit with its patch in
  31one file per commit, formatted to resemble UNIX mailbox format.
  32The output of this command is convenient for e-mail submission or
  33for use with 'git am'.
  34
  35There are two ways to specify which commits to operate on.
  36
  371. 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
  412. Generic <revision range> expression (see "SPECIFYING
  42   REVISIONS" section in linkgit:gitrevisions[7]) means the
  43   commits in the specified range.
  44
  45The first rule takes precedence in the case of a single <commit>.  To
  46apply the second rule, i.e., format everything since the beginning of
  47history up until <commit>, use the '\--root' option: `git format-patch
  48--root <commit>`.  If you want to format only <commit> itself, you
  49can do this with `git format-patch -1 <commit>`.
  50
  51By default, each output file is numbered sequentially from 1, and uses the
  52first line of the commit message (massaged for pathname safety) as
  53the filename. With the `--numbered-files` option, the output file names
  54will only be numbers, without the first line of the commit appended.
  55The names of the output files are printed to standard
  56output, unless the `--stdout` option is specified.
  57
  58If `-o` is specified, output files are created in <dir>.  Otherwise
  59they are created in the current working directory.
  60
  61By default, the subject of a single patch is "[PATCH] " followed by
  62the concatenation of lines from the commit message up to the first blank
  63line (see the DISCUSSION section of linkgit:git-commit[1]).
  64
  65When 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`.
  67To omit patch numbers from the subject, use `-N`.
  68
  69If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
  70`References` headers to make the second and subsequent patch mails appear
  71as replies to the first mail; this also generates a `Message-Id` header to
  72reference.
  73
  74OPTIONS
  75-------
  76:git-format-patch: 1
  77include::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+
 137The optional <style> argument can be either `shallow` or `deep`.
 138'shallow' threading makes every mail a reply to the head of the
 139series, where the head is chosen from the cover letter, the
 140`--in-reply-to`, and the first patch mail, in this order.  'deep'
 141threading makes every mail a reply to the previous one.
 142+
 143The default is `--no-thread`, unless the 'format.thread' configuration
 144is set.  If `--thread` is specified without a style, it defaults to the
 145style specified by 'format.thread' if any, or else `shallow`.
 146+
 147Beware that the default for 'git send-email' is to thread emails
 148itself.  If you want `git format-patch` to take care of threading, you
 149will 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+
 206Note that the leading character does not have to be a dot; for example,
 207you 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
 225CONFIGURATION
 226-------------
 227You can specify extra mail header lines to be added to each message,
 228defaults for the subject prefix and file suffix, number patches when
 229outputting more than one patch, add "To" or "Cc:" headers, configure
 230attachments, 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
 245DISCUSSION
 246----------
 247
 248The patch produced by 'git format-patch' is in UNIX mailbox format,
 249with a fixed "magic" time stamp to indicate that the file is output
 250from format-patch rather than a real mailbox, like so:
 251
 252------------
 253From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
 254From: Tony Luck <tony.luck@intel.com>
 255Date: Tue, 13 Jul 2010 11:42:54 -0700
 256Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
 257 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
 258MIME-Version: 1.0
 259Content-Type: text/plain; charset=UTF-8
 260Content-Transfer-Encoding: 8bit
 261
 262arch/arm config files were slimmed down using a python script
 263(See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
 264
 265Do the same for ia64 so we can have sleek & trim looking
 266...
 267------------
 268
 269Typically it will be placed in a MUA's drafts folder, edited to add
 270timely commentary that should not go in the changelog after the three
 271dashes, and then sent as a message whose body, in our example, starts
 272with "arch/arm config files were...".  On the receiving end, readers
 273can save interesting patches in a UNIX mailbox and apply them with
 274linkgit:git-am[1].
 275
 276When 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
 279line that consists solely of "`-- >8 --`" (scissors and perforation),
 280followed by the patch with unnecessary header fields removed:
 281
 282------------
 283...
 284> So we should do such-and-such.
 285
 286Makes sense to me.  How about this patch?
 287
 288-- >8 --
 289Subject: [IA64] Put ia64 config files on the Uwe Kleine-König diet
 290
 291arch/arm config files were slimmed down using a python script
 292...
 293------------
 294
 295When sending a patch this way, most often you are sending your own
 296patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
 297should omit `From:` and `Date:` lines from the patch file.  The patch
 298title is likely to be different from the subject of the discussion the
 299patch is in response to, so it is likely that you would want to keep
 300the Subject: line, like the example above.
 301
 302Checking for patch corruption
 303~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 304Many mailers if not set up properly will corrupt whitespace.  Here are
 305two 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
 312One 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
 328If 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
 348MUA-SPECIFIC HINTS
 349------------------
 350Here are some hints on how to successfully submit patches inline using
 351various mailers.
 352
 353GMail
 354~~~~~
 355GMail does not have any way to turn off line wrapping in the web
 356interface, so it will mangle any emails that you send.  You can however
 357use "git send-email" and send your patches through the GMail SMTP server, or
 358use any IMAP email client to connect to the google IMAP server and forward
 359the emails through that.
 360
 361For hints on using 'git send-email' to send your patches through the
 362GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
 363
 364For hints on submission using the IMAP interface, see the EXAMPLE
 365section of linkgit:git-imap-send[1].
 366
 367Thunderbird
 368~~~~~~~~~~~
 369By default, Thunderbird will both wrap emails as well as flag
 370them as being 'format=flowed', both of which will make the
 371resulting email unusable by git.
 372
 373There are three different approaches: use an add-on to turn off line wraps,
 374configure Thunderbird to not mangle patches, or use
 375an external editor to keep Thunderbird from mangling the patches.
 376
 377Approach #1 (add-on)
 378^^^^^^^^^^^^^^^^^^^^
 379
 380Install the Toggle Word Wrap add-on that is available from
 381https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
 382It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
 383that 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
 385insert line breaks manually in any text that you type.
 386
 387Approach #2 (configuration)
 388^^^^^^^^^^^^^^^^^^^^^^^^^^^
 389Three steps:
 390
 3911. Configure your mail server composition as plain text:
 392   Edit...Account Settings...Composition & Addressing,
 393   uncheck "Compose Messages in HTML".
 394
 3952. Configure your general composition window to not wrap.
 396+
 397In Thunderbird 2:
 398Edit..Preferences..Composition, wrap plain text messages at 0
 399+
 400In Thunderbird 3:
 401Edit..Preferences..Advanced..Config Editor.  Search for
 402"mail.wrap_long_lines".
 403Toggle it to make sure it is set to `false`.
 404
 4053. Disable the use of format=flowed:
 406Edit..Preferences..Advanced..Config Editor.  Search for
 407"mailnews.send_plaintext_flowed".
 408Toggle it to make sure it is set to `false`.
 409
 410After that is done, you should be able to compose email as you
 411otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
 412and the patches will not be mangled.
 413
 414Approach #3 (external editor)
 415^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 416
 417The following Thunderbird extensions are needed:
 418AboutConfig from http://aboutconfig.mozdev.org/ and
 419External Editor from http://globs.org/articles.php?lng=en&pg=8
 420
 4211. Prepare the patch as a text file using your method of choice.
 422
 4232. 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
 4283. 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
 4374. Open a compose window and click the external editor icon.
 438
 4395. In the external editor window, read in the patch file and exit
 440   the editor normally.
 441
 442Side note: it may be possible to do step 2 with
 443about: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
 451There is a script in contrib/thunderbird-patch-inline which can help
 452you include patches with Thunderbird in an easy way. To use it, do the
 453steps above and then use the script as the external editor.
 454
 455KMail
 456~~~~~
 457This should help you to submit patches inline using KMail.
 458
 4591. Prepare the patch as a text file.
 460
 4612. Click on New Mail.
 462
 4633. Go under "Options" in the Composer window and be sure that
 464   "Word wrap" is not set.
 465
 4664. Use Message -> Insert file... and insert the patch.
 467
 4685. 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
 472EXAMPLES
 473--------
 474
 475* Extract commits between revisions R1 and R2, and apply them on top of
 476the 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
 483origin branch:
 484+
 485------------
 486$ git format-patch origin
 487------------
 488+
 489For 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
 492project:
 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+
 504Additionally, it detects and handles renames and complete rewrites
 505intelligently to produce a renaming patch.  A renaming patch reduces
 506the amount of text output, and generally makes it easier to review.
 507Note that non-git "patch" programs won't understand renaming patches, so
 508use 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
 511as e-mailable patches:
 512+
 513------------
 514$ git format-patch -3
 515------------
 516
 517SEE ALSO
 518--------
 519linkgit:git-am[1], linkgit:git-send-email[1]
 520
 521GIT
 522---
 523Part of the linkgit:git[1] suite