git-format-patch(1) Git Manual git-format-patch(1)
NAME
git-format-patch - Prepare patches for e-mail submission
SYNOPSIS
git format-patch [-k] [(-o|--output-directory) <dir> | --stdout]
[--no-thread | --thread[=<style>]]
[(--attach|--inline)[=<boundary>] | --no-attach]
[-s | --signoff]
[--signature=<signature> | --no-signature]
[--signature-file=<file>]
[-n | --numbered | -N | --no-numbered]
[--start-number <n>] [--numbered-files]
[--in-reply-to=<message-id>] [--suffix=.<sfx>]
[--ignore-if-in-upstream] [--always]
[--cover-from-description=<mode>]
[--rfc[=<rfc>]] [--subject-prefix=<subject-prefix>]
[(--reroll-count|-v) <n>]
[--to=<email>] [--cc=<email>]
[--[no-]cover-letter] [--quiet]
[--[no-]encode-email-headers]
[--no-notes | --notes[=<ref>]]
[--interdiff=<previous>]
[--range-diff=<previous> [--creation-factor=<percent>]]
[--filename-max-length=<n>]
[--progress]
[<common-diff-options>]
[ <since> | <revision-range> ]
DESCRIPTION
Prepare each non-merge commit with its "patch" in one "message" per
commit, formatted to resemble a UNIX mailbox. The output of this
command is convenient for e-mail submission or for use with git am.
A "message" generated by the command consists of three parts:
o A brief metadata header that begins with From <commit> with a fixed
Mon Sep 17 00:00:00 2001 datestamp to help programs like "file(1)"
to recognize that the file is an output from this command, fields
that record the author identity, the author date, and the title of
the change (taken from the first paragraph of the commit log
message).
o The second and subsequent paragraphs of the commit log message.
o The "patch", which is the "diff -p --stat" output (see git-diff(1))
between the commit and its parent.
The log message and the patch are separated by a line with a three-dash
line.
There are two ways to specify which commits to operate on.
1. A single commit, <since>, specifies that the commits leading to the
tip of the current branch that are not in the history that leads to
the <since> to be output.
2. Generic <revision-range> expression (see "SPECIFYING REVISIONS"
section in gitrevisions(7)) means the commits in the specified
range.
The first rule takes precedence in the case of a single <commit>. To
apply the second rule, i.e., format everything since the beginning of
history up until <commit>, use the --root option: git format-patch
--root <commit>. If you want to format only <commit> itself, you can do
this with git format-patch -1 <commit>.
By default, each output file is numbered sequentially from 1, and uses
the first line of the commit message (massaged for pathname safety) as
the filename. With the --numbered-files option, the output file names
will only be numbers, without the first line of the commit appended.
The names of the output files are printed to standard output, unless
the --stdout option is specified.
If -o is specified, output files are created in <dir>. Otherwise they
are created in the current working directory. The default path can be
set with the format.outputDirectory configuration option. The -o option
takes precedence over format.outputDirectory. To store patches in the
current working directory even when format.outputDirectory points
elsewhere, use -o .. All directory components will be created.
By default, the subject of a single patch is "[PATCH] " followed by the
concatenation of lines from the commit message up to the first blank
line (see the DISCUSSION section of git-commit(1)).
When multiple patches are output, the subject prefix will instead be
"[PATCH n/m] ". To force 1/1 to be added for a single patch, use -n. To
omit patch numbers from the subject, use -N.
If given --thread, git-format-patch will generate In-Reply-To and
References headers to make the second and subsequent patch mails appear
as replies to the first mail; this also generates a Message-ID header
to reference.
OPTIONS
-p, --no-stat
Generate plain patches without any diffstats.
-U<n>, --unified=<n>
Generate diffs with <n> lines of context instead of the usual
three.
--output=<file>
Output to a specific file instead of stdout.
--output-indicator-new=<char>, --output-indicator-old=<char>,
--output-indicator-context=<char>
Specify the character used to indicate new, old or context lines in
the generated patch. Normally they are +, - and ' ' respectively.
--indent-heuristic
Enable the heuristic that shifts diff hunk boundaries to make
patches easier to read. This is the default.
--no-indent-heuristic
Disable the indent heuristic.
--minimal
Spend extra time to make sure the smallest possible diff is
produced.
--patience
Generate a diff using the "patience diff" algorithm.
--histogram
Generate a diff using the "histogram diff" algorithm.
--anchored=<text>
Generate a diff using the "anchored diff" algorithm.
This option may be specified more than once.
If a line exists in both the source and destination, exists only
once, and starts with <text>, this algorithm attempts to prevent it
from appearing as a deletion or addition in the output. It uses the
"patience diff" algorithm internally.
--diff-algorithm=(patience|minimal|histogram|myers)
Choose a diff algorithm. The variants are as follows:
default, myers
The basic greedy diff algorithm. Currently, this is the
default.
minimal
Spend extra time to make sure the smallest possible diff is
produced.
patience
Use "patience diff" algorithm when generating patches.
histogram
This algorithm extends the patience algorithm to "support
low-occurrence common elements".
For instance, if you configured the diff.algorithm variable to a
non-default value and want to use the default one, then you have to
use --diff-algorithm=default option.
--stat[=<width>[,<name-width>[,<count>]]]
Generate a diffstat. By default, as much space as necessary will be
used for the filename part, and the rest for the graph part.
Maximum width defaults to terminal width, or 80 columns if not
connected to a terminal, and can be overridden by <width>. The
width of the filename part can be limited by giving another width
<name-width> after a comma or by setting
diff.statNameWidth=<name-width>. The width of the graph part can be
limited by using --stat-graph-width=<graph-width> or by setting
diff.statGraphWidth=<graph-width>. Using --stat or
--stat-graph-width affects all commands generating a stat graph,
while setting diff.statNameWidth or diff.statGraphWidth does not
affect git format-patch. By giving a third parameter <count>, you
can limit the output to the first <count> lines, followed by ... if
there are more.
These parameters can also be set individually with
--stat-width=<width>, --stat-name-width=<name-width> and
--stat-count=<count>.
--compact-summary
Output a condensed summary of extended header information such as
file creations or deletions ("new" or "gone", optionally +l if it's
a symlink) and mode changes (+x or -x for adding or removing
executable bit respectively) in diffstat. The information is put
between the filename part and the graph part. Implies --stat.
--numstat
Similar to --stat, but shows number of added and deleted lines in
decimal notation and pathname without abbreviation, to make it more
machine friendly. For binary files, outputs two - instead of saying
0 0.
--shortstat
Output only the last line of the --stat format containing total
number of modified files, as well as number of added and deleted
lines.
-X [<param>,...], --dirstat[=<param>,...]
Output the distribution of relative amount of changes for each
sub-directory. The behavior of --dirstat can be customized by
passing it a comma separated list of parameters. The defaults are
controlled by the diff.dirstat configuration variable (see git-
config(1)). The following parameters are available:
changes
Compute the dirstat numbers by counting the lines that have
been removed from the source, or added to the destination. This
ignores the amount of pure code movements within a file. In
other words, rearranging lines in a file is not counted as much
as other changes. This is the default behavior when no
parameter is given.
lines
Compute the dirstat numbers by doing the regular line-based
diff analysis, and summing the removed/added line counts. (For
binary files, count 64-byte chunks instead, since binary files
have no natural concept of lines). This is a more expensive
--dirstat behavior than the changes behavior, but it does count
rearranged lines within a file as much as other changes. The
resulting output is consistent with what you get from the other
--*stat options.
files
Compute the dirstat numbers by counting the number of files
changed. Each changed file counts equally in the dirstat
analysis. This is the computationally cheapest --dirstat
behavior, since it does not have to look at the file contents
at all.
cumulative
Count changes in a child directory for the parent directory as
well. Note that when using cumulative, the sum of the
percentages reported may exceed 100%. The default
(non-cumulative) behavior can be specified with the
noncumulative parameter.
<limit>
An integer parameter specifies a cut-off percent (3% by
default). Directories contributing less than this percentage of
the changes are not shown in the output.
Example: The following will count changed files, while ignoring
directories with less than 10% of the total amount of changed
files, and accumulating child directory counts in the parent
directories: --dirstat=files,10,cumulative.
--cumulative
Synonym for --dirstat=cumulative.
--dirstat-by-file[=<param>,...]
Synonym for --dirstat=files,<param>,....
--summary
Output a condensed summary of extended header information such as
creations, renames and mode changes.
--no-renames
Turn off rename detection, even when the configuration file gives
the default to do so.
--[no-]rename-empty
Whether to use empty blobs as rename source.
--full-index
Instead of the first handful of characters, show the full pre- and
post-image blob object names on the "index" line when generating
patch format output.
--binary
In addition to --full-index, output a binary diff that can be
applied with git-apply.
--abbrev[=<n>]
Instead of showing the full 40-byte hexadecimal object name in
diff-raw format output and diff-tree header lines, show the
shortest prefix that is at least <n> hexdigits long that uniquely
refers the object. In diff-patch output format, --full-index takes
higher precedence, i.e. if --full-index is specified, full blob
names will be shown regardless of --abbrev. Non default number of
digits can be specified with --abbrev=<n>.
-B[<n>][/<m>], --break-rewrites[=[<n>][/<m>]]
Break complete rewrite changes into pairs of delete and create.
This serves two purposes:
It affects the way a change that amounts to a total rewrite of a
file not as a series of deletion and insertion mixed together with
a very few lines that happen to match textually as the context, but
as a single deletion of everything old followed by a single
insertion of everything new, and the number <m> controls this
aspect of the -B option (defaults to 60%). -B/70% specifies that
less than 30% of the original should remain in the result for Git
to consider it a total rewrite (i.e. otherwise the resulting patch
will be a series of deletion and insertion mixed together with
context lines).
When used with -M, a totally-rewritten file is also considered as
the source of a rename (usually -M only considers a file that
disappeared as the source of a rename), and the number <n> controls
this aspect of the -B option (defaults to 50%). -B20% specifies
that a change with addition and deletion compared to 20% or more of
the file's size are eligible for being picked up as a possible
source of a rename to another file.
-M[<n>], --find-renames[=<n>]
Detect renames. If <n> is specified, it is a threshold on the
similarity index (i.e. amount of addition/deletions compared to the
file's size). For example, -M90% means Git should consider a
delete/add pair to be a rename if more than 90% of the file hasn't
changed. Without a % sign, the number is to be read as a fraction,
with a decimal point before it. I.e., -M5 becomes 0.5, and is thus
the same as -M50%. Similarly, -M05 is the same as -M5%. To limit
detection to exact renames, use -M100%. The default similarity
index is 50%.
-C[<n>], --find-copies[=<n>]
Detect copies as well as renames. See also --find-copies-harder. If
<n> is specified, it has the same meaning as for -M<n>.
--find-copies-harder
For performance reasons, by default, -C option finds copies only if
the original file of the copy was modified in the same changeset.
This flag makes the command inspect unmodified files as candidates
for the source of copy. This is a very expensive operation for
large projects, so use it with caution. Giving more than one -C
option has the same effect.
-D, --irreversible-delete
Omit the preimage for deletes, i.e. print only the header but not
the diff between the preimage and /dev/null. The resulting patch is
not meant to be applied with patch or git apply; this is solely for
people who want to just concentrate on reviewing the text after the
change. In addition, the output obviously lacks enough information
to apply such a patch in reverse, even manually, hence the name of
the option.
When used together with -B, omit also the preimage in the deletion
part of a delete/create pair.
-l<num>
The -M and -C options involve some preliminary steps that can
detect subsets of renames/copies cheaply, followed by an exhaustive
fallback portion that compares all remaining unpaired destinations
to all relevant sources. (For renames, only remaining unpaired
sources are relevant; for copies, all original sources are
relevant.) For N sources and destinations, this exhaustive check is
O(N^2). This option prevents the exhaustive portion of rename/copy
detection from running if the number of source/destination files
involved exceeds the specified number. Defaults to
diff.renameLimit. Note that a value of 0 is treated as unlimited.
-O<orderfile>
Control the order in which files appear in the output. This
overrides the diff.orderFile configuration variable (see git-
config(1)). To cancel diff.orderFile, use -O/dev/null.
The output order is determined by the order of glob patterns in
<orderfile>. All files with pathnames that match the first pattern
are output first, all files with pathnames that match the second
pattern (but not the first) are output next, and so on. All files
with pathnames that do not match any pattern are output last, as if
there was an implicit match-all pattern at the end of the file. If
multiple pathnames have the same rank (they match the same pattern
but no earlier patterns), their output order relative to each other
is the normal order.
<orderfile> is parsed as follows:
o Blank lines are ignored, so they can be used as separators for
readability.
o Lines starting with a hash ("#") are ignored, so they can be
used for comments. Add a backslash ("\") to the beginning of
the pattern if it starts with a hash.
o Each other line contains a single pattern.
Patterns have the same syntax and semantics as patterns used for
fnmatch(3) without the FNM_PATHNAME flag, except a pathname also
matches a pattern if removing any number of the final pathname
components matches the pattern. For example, the pattern "foo*bar"
matches "fooasdfbar" and "foo/bar/baz/asdf" but not "foobarx".
--skip-to=<file>, --rotate-to=<file>
Discard the files before the named <file> from the output (i.e.
skip to), or move them to the end of the output (i.e. rotate to).
These options were invented primarily for the use of the git
difftool command, and may not be very useful otherwise.
--relative[=<path>], --no-relative
When run from a subdirectory of the project, it can be told to
exclude changes outside the directory and show pathnames relative
to it with this option. When you are not in a subdirectory (e.g. in
a bare repository), you can name which subdirectory to make the
output relative to by giving a <path> as an argument.
--no-relative can be used to countermand both diff.relative config
option and previous --relative.
-a, --text
Treat all files as text.
--ignore-cr-at-eol
Ignore carriage-return at the end of line when doing a comparison.
--ignore-space-at-eol
Ignore changes in whitespace at EOL.
-b, --ignore-space-change
Ignore changes in amount of whitespace. This ignores whitespace at
line end, and considers all other sequences of one or more
whitespace characters to be equivalent.
-w, --ignore-all-space
Ignore whitespace when comparing lines. This ignores differences
even if one line has whitespace where the other line has none.
--ignore-blank-lines
Ignore changes whose lines are all blank.
-I<regex>, --ignore-matching-lines=<regex>
Ignore changes whose all lines match <regex>. This option may be
specified more than once.
--inter-hunk-context=<number>
Show the context between diff hunks, up to the specified <number>
of lines, thereby fusing hunks that are close to each other.
Defaults to diff.interHunkContext or 0 if the config option is
unset.
-W, --function-context
Show whole function as context lines for each change. The function
names are determined in the same way as git diff works out patch
hunk headers (see "Defining a custom hunk-header" in
gitattributes(5)).
--ext-diff
Allow an external diff helper to be executed. If you set an
external diff driver with gitattributes(5), you need to use this
option with git-log(1) and friends.
--no-ext-diff
Disallow external diff drivers.
--textconv, --no-textconv
Allow (or disallow) external text conversion filters to be run when
comparing binary files. See gitattributes(5) for details. Because
textconv filters are typically a one-way conversion, the resulting
diff is suitable for human consumption, but cannot be applied. For
this reason, textconv filters are enabled by default only for git-
git-format-patch(1) or diff
plumbing commands.
--ignore-submodules[=(none|untracked|dirty|all)]
Ignore changes to submodules in the diff generation. all is the
default. Using none will consider the submodule modified when it
either contains untracked or modified files or its HEAD differs
from the commit recorded in the superproject and can be used to
override any settings of the ignore option in git-config(1) or
gitmodules(5). When untracked is used submodules are not considered
dirty when they only contain untracked content (but they are still
scanned for modified content). Using dirty ignores all changes to
the work tree of submodules, only changes to the commits stored in
the superproject are shown (this was the behavior until 1.7.0).
Using all hides all changes to submodules.
--src-prefix=<prefix>
Show the given source <prefix> instead of "a/".
--dst-prefix=<prefix>
Show the given destination <prefix> instead of "b/".
--no-prefix
Do not show any source or destination prefix.
--default-prefix
Use the default source and destination prefixes ("a/" and "b/").
This overrides configuration variables such as diff.noprefix,
diff.srcPrefix, diff.dstPrefix, and diff.mnemonicPrefix (see git-
config(1)).
--line-prefix=<prefix>
Prepend an additional <prefix> to every line of output.
--ita-invisible-in-index
By default entries added by git add -N appear as an existing empty
file in git diff and a new file in git diff --cached. This option
makes the entry appear as a new file in git diff and non-existent
in git diff --cached. This option could be reverted with
--ita-visible-in-index. Both options are experimental and could be
removed in future.
For more detailed explanation on these common options, see also
gitdiffcore(7).
-<n>
Prepare patches from the topmost <n> commits.
-o <dir>, --output-directory <dir>
Use <dir> to store the resulting files, instead of the current
working directory.
-n, --numbered
Name output in [PATCH n/m] format, even with a single patch.
-N, --no-numbered
Name output in [PATCH] format.
--start-number <n>
Start numbering the patches at <n> instead of 1.
--numbered-files
Output file names will be a simple number sequence without the
default first line of the commit appended.
-k, --keep-subject
Do not strip/add [PATCH] from the first line of the commit log
message.
-s, --signoff
Add a Signed-off-by trailer to the commit message, using the
committer identity of yourself. See the signoff option in git-
commit(1) for more information.
--stdout
Print all commits to the standard output in mbox format, instead of
creating a file for each one.
--attach[=<boundary>]
Create multipart/mixed attachment, the first part of which is the
commit message and the patch itself in the second part, with
Content-Disposition: attachment.
--no-attach
Disable the creation of an attachment, overriding the configuration
setting.
--inline[=<boundary>]
Create multipart/mixed attachment, the first part of which is the
commit message and the patch itself in the second part, with
Content-Disposition: inline.
--thread[=<style>], --no-thread
Controls addition of In-Reply-To and References headers to make the
second and subsequent mails appear as replies to the first. Also
controls generation of the Message-ID header to reference.
The optional <style> argument can be either shallow or deep.
shallow threading makes every mail a reply to the head of the
series, where the head is chosen from the cover letter, the
--in-reply-to, and the first patch mail, in this order. deep
threading makes every mail a reply to the previous one.
The default is --no-thread, unless the format.thread configuration
is set. --thread without an argument is equivalent to
--thread=shallow.
Beware that the default for git send-email is to thread emails
itself. If you want git format-patch to take care of threading, you
will want to ensure that threading is disabled for git send-email.
--in-reply-to=<message-id>
Make the first mail (or all the mails with --no-thread) appear as a
reply to the given <message-id>, which avoids breaking threads to
provide a new patch series.
--ignore-if-in-upstream
Do not include a patch that matches a commit in <until>..<since>.
This will examine all patches reachable from <since> but not from
<until> and compare them with the patches being generated, and any
patch that matches is ignored.
--always
Include patches for commits that do not introduce any change, which
are omitted by default.
--cover-from-description=<mode>
Controls which parts of the cover letter will be automatically
populated using the branch's description.
If <mode> is message or default, the cover letter subject will be
populated with placeholder text. The body of the cover letter will
be populated with the branch's description. This is the default
mode when no configuration nor command line option is specified.
If <mode> is subject, the first paragraph of the branch description
will populate the cover letter subject. The remainder of the
description will populate the body of the cover letter.
If <mode> is auto, if the first paragraph of the branch description
is greater than 100 bytes, then the mode will be message, otherwise
subject will be used.
If <mode> is none, both the cover letter subject and body will be
populated with placeholder text.
--description-file=<file>
Use the contents of <file> instead of the branch's description for
generating the cover letter.
--subject-prefix=<subject-prefix>
Instead of the standard [PATCH] prefix in the subject line, instead
use [<subject-prefix>]. This can be used to name a patch series,
and can be combined with the --numbered option.
The configuration variable format.subjectPrefix may also be used to
configure a subject prefix to apply to a given repository for all
patches. This is often useful on mailing lists which receive
patches for several repositories and can be used to disambiguate
the patches (with a value of e.g. "PATCH my-project").
--filename-max-length=<n>
Instead of the standard 64 bytes, chomp the generated output
filenames at around <n> bytes (too short a value will be silently
raised to a reasonable length). Defaults to the value of the
format.filenameMaxLength configuration variable, or 64 if
unconfigured.
--rfc[=<rfc>]
Prepends the string <rfc> (defaults to "RFC") to the subject
prefix. As the subject prefix defaults to "PATCH", you'll get "RFC
PATCH" by default.
RFC means "Request For Comments"; use this when sending an
experimental patch for discussion rather than application.
"--rfc=WIP" may also be a useful way to indicate that a patch is
not complete yet ("WIP" stands for "Work In Progress").
If the convention of the receiving community for a particular extra
string is to have it after the subject prefix, the string <rfc> can
be prefixed with a dash ("-") to signal that the rest of the <rfc>
string should be appended to the subject prefix instead, e.g.,
--rfc='-(WIP)' results in "PATCH (WIP)".
-v <n>, --reroll-count=<n>
Mark the series as the <n>-th iteration of the topic. The output
filenames have v<n> prepended to them, and the subject prefix
("PATCH" by default, but configurable via the --subject-prefix
option) has ` v<n>` appended to it. E.g. --reroll-count=4 may
produce v4-0001-add-makefile.patch file that has "Subject: [PATCH
v4 1/20] Add makefile" in it. <n> does not have to be an integer
(e.g. "--reroll-count=4.4", or "--reroll-count=4rev2" are allowed),
but the downside of using such a reroll-count is that the
range-diff/interdiff with the previous version does not state
exactly which version the new iteration is compared against.
--to=<email>
Add a To: header to the email headers. This is in addition to any
configured headers, and may be used multiple times. The negated
form --no-to discards all To: headers added so far (from config or
command line).
--cc=<email>
Add a Cc: header to the email headers. This is in addition to any
configured headers, and may be used multiple times. The negated
form --no-cc discards all Cc: headers added so far (from config or
command line).
--from, --from=<ident>
Use ident in the From: header of each commit email. If the author
ident of the commit is not textually identical to the provided
ident, place a From: header in the body of the message with the
original author. If no ident is given, use the committer ident.
Note that this option is only useful if you are actually sending
the emails and want to identify yourself as the sender, but retain
the original author (and git am will correctly pick up the in-body
header). Note also that git send-email already handles this
transformation for you, and this option should not be used if you
are feeding the result to git send-email.
--[no-]force-in-body-from
With the e-mail sender specified via the --from option, by default,
an in-body "From:" to identify the real author of the commit is
added at the top of the commit log message if the sender is
different from the author. With this option, the in-body "From:" is
added even when the sender and the author have the same name and
address, which may help if the mailing list software mangles the
sender's identity. Defaults to the value of the
format.forceInBodyFrom configuration variable.
--add-header=<header>
Add an arbitrary header to the email headers. This is in addition
to any configured headers, and may be used multiple times. For
example, --add-header="Organization: git-foo". The negated form
--no-add-header discards all (To:, Cc:, and custom) headers added
so far from config or command line.
--[no-]cover-letter
In addition to the patches, generate a cover letter file containing
the branch description, shortlog and the overall diffstat. You can
fill in a description in the file before sending it out.
--encode-email-headers, --no-encode-email-headers
Encode email headers that have non-ASCII characters with
"Q-encoding" (described in RFC 2047), instead of outputting the
headers verbatim. Defaults to the value of the
format.encodeEmailHeaders configuration variable.
--interdiff=<previous>
As a reviewer aid, insert an interdiff into the cover letter, or as
commentary of the lone patch of a 1-patch series, showing the
differences between the previous version of the patch series and
the series currently being formatted. previous is a single
revision naming the tip of the previous series which shares a
common base with the series being formatted (for example git
format-patch --cover-letter --interdiff=feature/v1 -3 feature/v2).
--range-diff=<previous>
As a reviewer aid, insert a range-diff (see git-range-diff(1)) into
the cover letter, or as commentary of the lone patch of a 1-patch
series, showing the differences between the previous version of the
patch series and the series currently being formatted. previous
can be a single revision naming the tip of the previous series if
it shares a common base with the series being formatted (for
example git format-patch --cover-letter --range-diff=feature/v1 -3
feature/v2), or a revision range if the two versions of the series
are disjoint (for example git format-patch --cover-letter
--range-diff=feature/v1~3..feature/v1 -3 feature/v2).
Note that diff options passed to the command affect how the primary
product of format-patch is generated, and they are not passed to
the underlying range-diff machinery used to generate the
cover-letter material (this may change in the future).
--creation-factor=<percent>
Used with --range-diff, tweak the heuristic which matches up
commits between the previous and current series of patches by
adjusting the creation/deletion cost fudge factor. See git-range-
diff(1)) for details.
Defaults to 999 (the git-range-diff(1) uses 60), as the use case is
to show comparison with an older iteration of the same topic and
the tool should find more correspondence between the two sets of
patches.
--notes[=<ref>], --no-notes
Append the notes (see git-notes(1)) for the commit after the
three-dash line.
The expected use case of this is to write supporting explanation
for the commit that does not belong to the commit log message
proper, and include it with the patch submission. While one can
simply write these explanations after format-patch has run but
before sending, keeping them as Git notes allows them to be
maintained between versions of the patch series (but see the
discussion of the notes.rewrite configuration options in git-
notes(1) to use this workflow).
The default is --no-notes, unless the format.notes configuration is
set.
--[no-]signature=<signature>
Add a signature to each message produced. Per RFC 3676 the
signature is separated from the body by a line with '-- ' on it. If
the signature option is omitted the signature defaults to the Git
version number.
--signature-file=<file>
Works just like --signature except the signature is read from a
file.
--suffix=.<sfx>
Instead of using .patch as the suffix for generated filenames, use
specified suffix. A common alternative is --suffix=.txt. Leaving
this empty will remove the .patch suffix.
Note that the leading character does not have to be a dot; for
example, you can use --suffix=-patch to get
0001-description-of-my-change-patch.
-q, --quiet
Do not print the names of the generated files to standard output.
--no-binary
Do not output contents of changes in binary files, instead display
a notice that those files changed. Patches generated using this
option cannot be applied properly, but they are still useful for
code review.
--zero-commit
Output an all-zero hash in each patch's From header instead of the
hash of the commit.
--[no-]base[=<commit>]
Record the base tree information to identify the state the patch
series applies to. See the BASE TREE INFORMATION section below for
details. If <commit> is "auto", a base commit is automatically
chosen. The --no-base option overrides a format.useAutoBase
configuration.
--root
Treat the revision argument as a <revision-range>, even if it is
just a single commit (that would normally be treated as a <since>).
Note that root commits included in the specified range are always
formatted as creation patches, independently of this flag.
--progress
Show progress reports on stderr as patches are generated.
CONFIGURATION
You can specify extra mail header lines to be added to each message,
defaults for the subject prefix and file suffix, number patches when
outputting more than one patch, add "To:" or "Cc:" headers, configure
attachments, change the patch output directory, and sign off patches
with configuration variables.
[format]
headers = "Organization: git-foo\n"
subjectPrefix = CHANGE
suffix = .txt
numbered = auto
to = <email>
cc = <email>
attach [ = mime-boundary-string ]
signOff = true
outputDirectory = <directory>
coverLetter = auto
coverFromDescription = auto
DISCUSSION
The patch produced by git format-patch is in UNIX mailbox format, with
a fixed "magic" time stamp to indicate that the file is output from
format-patch rather than a real mailbox, like so:
From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
From: Tony Luck <tony.luck@intel.com>
Date: Tue, 13 Jul 2010 11:42:54 -0700
Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
arch/arm config files were slimmed down using a python script
(See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
Do the same for ia64 so we can have sleek & trim looking
...
Typically it will be placed in a MUA's drafts folder, edited to add
timely commentary that should not go in the changelog after the three
dashes, and then sent as a message whose body, in our example, starts
with "arch/arm config files were...". On the receiving end, readers can
save interesting patches in a UNIX mailbox and apply them with git-
am(1).
When a patch is part of an ongoing discussion, the patch generated by
git format-patch can be tweaked to take advantage of the git am
--scissors feature. After your response to the discussion comes a line
that consists solely of "-- >8 --" (scissors and perforation), followed
by the patch with unnecessary header fields removed:
...
> So we should do such-and-such.
Makes sense to me. How about this patch?
-- >8 --
Subject: [IA64] Put ia64 config files on the Uwe Kleine-Konig diet
arch/arm config files were slimmed down using a python script
...
When sending a patch this way, most often you are sending your own
patch, so in addition to the "From $SHA1 $magic_timestamp" marker you
should omit From: and Date: lines from the patch file. The patch title
is likely to be different from the subject of the discussion the patch
is in response to, so it is likely that you would want to keep the
Subject: line, like the example above.
Checking for patch corruption
Many mailers if not set up properly will corrupt whitespace. Here are
two common types of corruption:
o Empty context lines that do not have any whitespace.
o Non-empty context lines that have one extra whitespace at the
beginning.
One way to test if your MUA is set up correctly is:
o Send the patch to yourself, exactly the way you would, except with
To: and Cc: lines that do not contain the list and maintainer
address.
o Save that patch to a file in UNIX mailbox format. Call it a.patch,
say.
o Apply it:
$ git fetch <project> master:test-apply
$ git switch test-apply
$ git restore --source=HEAD --staged --worktree :/
$ git am a.patch
If it does not apply correctly, there can be various reasons.
o The patch itself does not apply cleanly. That is bad but does not
have much to do with your MUA. You might want to rebase the patch
with git-rebase(1) before regenerating it in this case.
o The MUA corrupted your patch; "am" would complain that the patch
does not apply. Look in the .git/rebase-apply/ subdirectory and see
what patch file contains and check for the common corruption
patterns mentioned above.
o While at it, check the info and final-commit files as well. If what
is in final-commit is not exactly what you would want to see in the
commit log message, it is very likely that the receiver would end
up hand editing the log message when applying your patch. Things
like "Hi, this is my first patch.\n" in the patch e-mail should
come after the three-dash line that signals the end of the commit
message.
MUA-SPECIFIC HINTS
Here are some hints on how to successfully submit patches inline using
various mailers.
GMail
GMail does not have any way to turn off line wrapping in the web
interface, so it will mangle any emails that you send. You can however
use "git send-email" and send your patches through the GMail SMTP
server, or use any IMAP email client to connect to the google IMAP
server and forward the emails through that.
For hints on using git send-email to send your patches through the
GMail SMTP server, see the EXAMPLE section of git-send-email(1).
For hints on submission using the IMAP interface, see the EXAMPLE
section of git-imap-send(1).
Thunderbird
By default, Thunderbird will both wrap emails as well as flag them as
being format=flowed, both of which will make the resulting email
unusable by Git.
There are three different approaches: use an add-on to turn off line
wraps, configure Thunderbird to not mangle patches, or use an external
editor to keep Thunderbird from mangling the patches.
Approach #1 (add-on)
Install the Toggle Word Wrap add-on that is available from
https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/ It
adds a menu entry "Enable Word Wrap" in the composer's "Options"
menu that you can tick off. Now you can compose the message as you
otherwise do (cut + paste, git format-patch | git imap-send, etc),
but you have to insert line breaks manually in any text that you
type.
Approach #2 (configuration)
Three steps:
1. Configure your mail server composition as plain text: Edit...
Account Settings...Composition & Addressing, uncheck "Compose
Messages in HTML".
2. Configure your general composition window to not wrap.
In Thunderbird 2: Edit..Preferences..Composition, wrap plain
text messages at 0
In Thunderbird 3: Edit..Preferences..Advanced..Config Editor.
Search for "mail.wrap_long_lines". Toggle it to make sure it is
set to false. Also, search for "mailnews.wraplength" and set
the value to 0.
3. Disable the use of format=flowed:
Edit..Preferences..Advanced..Config Editor. Search for
"mailnews.send_plaintext_flowed". Toggle it to make sure it is
set to false.
After that is done, you should be able to compose email as you
otherwise would (cut + paste, git format-patch | git imap-send,
etc), and the patches will not be mangled.
Approach #3 (external editor)
The following Thunderbird extensions are needed: AboutConfig from
https://mjg.github.io/AboutConfig/ and External Editor from
https://globs.org/articles.php?lng=en&pg=8
1. Prepare the patch as a text file using your method of choice.
2. Before opening a compose window, use Edit->Account Settings to
uncheck the "Compose messages in HTML format" setting in the
"Composition & Addressing" panel of the account to be used to
send the patch.
3. In the main Thunderbird window, before you open the compose
window for the patch, use Tools->about:config to set the
following to the indicated values:
mailnews.send_plaintext_flowed => false
mailnews.wraplength => 0
4. Open a compose window and click the external editor icon.
5. In the external editor window, read in the patch file and exit
the editor normally.
Side note: it may be possible to do step 2 with about:config and
the following settings but no one's tried yet.
mail.html_compose => false
mail.identity.default.compose_html => false
mail.identity.id?.compose_html => false
There is a script in contrib/thunderbird-patch-inline which can
help you include patches with Thunderbird in an easy way. To use
it, do the steps above and then use the script as the external
editor.
KMail
This should help you to submit patches inline using KMail.
1. Prepare the patch as a text file.
2. Click on New Mail.
3. Go under "Options" in the Composer window and be sure that "Word
wrap" is not set.
4. Use Message -> Insert file... and insert the patch.
5. Back in the compose window: add whatever other text you wish to the
message, complete the addressing and subject fields, and press
send.
BASE TREE INFORMATION
The base tree information block is used for maintainers or third party
testers to know the exact state the patch series applies to. It
consists of the base commit, which is a well-known commit that is part
of the stable part of the project history everybody else works off of,
and zero or more prerequisite patches, which are well-known patches in
flight that is not yet part of the base commit that need to be applied
on top of base commit in topological order before the patches can be
applied.
The base commit is shown as "base-commit: " followed by the 40-hex of
the commit object name. A prerequisite patch is shown as
"prerequisite-patch-id: " followed by the 40-hex patch id, which can be
obtained by passing the patch through the git patch-id --stable
command.
Imagine that on top of the public commit P, you applied well-known
patches X, Y and Z from somebody else, and then built your three-patch
series A, B, C, the history would be like:
---P---X---Y---Z---A---B---C
With git format-patch --base=P -3 C (or variants thereof, e.g. with
--cover-letter or using Z..C instead of -3 C to specify the range), the
base tree information block is shown at the end of the first message
the command outputs (either the first patch, or the cover letter), like
this:
base-commit: P
prerequisite-patch-id: X
prerequisite-patch-id: Y
prerequisite-patch-id: Z
For non-linear topology, such as
---P---X---A---M---C
\ /
Y---Z---B
You can also use git format-patch --base=P -3 C to generate patches for
A, B and C, and the identifiers for P, X, Y, Z are appended at the end
of the first message.
If set --base=auto in cmdline, it will automatically compute the base
commit as the merge base of tip commit of the remote-tracking branch
and revision-range specified in cmdline. For a local branch, you need
to make it to track a remote branch by git branch --set-upstream-to
before using this option.
EXAMPLES
o Extract commits between revisions R1 and R2, and apply them on top
of the current branch using git am to cherry-pick them:
$ git format-patch -k --stdout R1..R2 | git am -3 -k
o Extract all commits which are in the current branch but not in the
origin branch:
$ git format-patch origin
For each commit a separate file is created in the current
directory.
o Extract all commits that lead to origin since the inception of the
project:
$ git format-patch --root origin
o The same as the previous one:
$ git format-patch -M -B origin
Additionally, it detects and handles renames and complete rewrites
intelligently to produce a renaming patch. A renaming patch reduces
the amount of text output, and generally makes it easier to review.
Note that non-Git "patch" programs won't understand renaming
patches, so use it only when you know the recipient uses Git to
apply your patch.
o Extract three topmost commits from the current branch and format
them as e-mailable patches:
$ git format-patch -3
CAVEATS
Note that format-patch will omit merge commits from the output, even if
they are part of the requested range. A simple "patch" does not include
enough information for the receiving end to reproduce the same merge
commit.
SEE ALSO
git-am(1), git-send-email(1)
GIT
Part of the git(1) suite
Git 2.48.0 2025-01-10 git-format-patch(1)
git 2.48.0 - Generated Sat Jan 11 13:19:01 CST 2025