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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] [--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:
• 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).
• The second and subsequent paragraphs of the commit log message.
• 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
this 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=<width>. The width of the graph part
can be limited by using --stat-graph-width=<width> or by setting
diff.statGraphWidth=<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[<param1,param2,...>], --dirstat[=<param1,param2,...>]
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[=<param1,param2>...]
Synonym for --dirstat=files,param1,param2...
--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:
• Blank lines are ignored, so they can be used as separators for readability.
• 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.
• 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=<lines>
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-
diff(1) and git-log(1), but not for git-format-patch(1) or diff plumbing commands.
--ignore-submodules[=<when>]
Ignore changes to submodules in the diff generation. <when> can be either "none",
"untracked", "dirty" or "all", which 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 is usually the
default already, but may be used to override config such as diff.noprefix.
--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
Prepends "RFC" to the subject prefix (producing "RFC PATCH" by default). RFC means
"Request For Comments"; use this when sending an experimental patch for discussion
rather than application.
-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.
--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-König 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:
• Empty context lines that do not have any whitespace.
• Non-empty context lines that have one extra whitespace at the beginning.
One way to test if your MUA is set up correctly is:
• 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.
• Save that patch to a file in UNIX mailbox format. Call it a.patch, say.
• 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.
• 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.
• 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.
• 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
http://aboutconfig.mozdev.org/ and External Editor from
http://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
• 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
• 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.
• Extract all commits that lead to origin since the inception of the project:
$ git format-patch --root origin
• 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.
• 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