git-format-patch
(1)Prepare patches for e-mail submission
Options
88-p--no-statGenerate plain patches without any diffstats.
-U--unifiedGenerate diffs with <n> lines of context instead of the usual three.
--outputOutput to a specific file instead of stdout.
--output-indicator-new--output-indicator-old--output-indicator-contextSpecify the character used to indicate new, old or context lines in the generated patch. Normally they are +, - and ' ' respectively.
--indent-heuristicEnable the heuristic that shifts diff hunk boundaries to make patches easier to read. This is the default.
--no-indent-heuristicDisable the indent heuristic.
--minimalSpend extra time to make sure the smallest possible diff is produced.
--patienceGenerate a diff using the "patience diff" algorithm.
--histogramGenerate a diff using the "histogram diff" algorithm.
--anchoredGenerate 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-algorithmChoose 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.
--statGenerate 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 s
--compact-summaryOutput 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.
--numstatSimilar 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.
--shortstatOutput only the last line of the --stat format containing total number of modified files, as well as number of added and deleted lines.
-X--dirstatOutput 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
--cumulativeSynonym for --dirstat=cumulative
--dirstat-by-fileSynonym for --dirstat=files,<param1>,<param2>...
--summaryOutput a condensed summary of extended header information such as creations, renames and mode changes.
--no-renamesTurn off rename detection, even when the configuration file gives the default to do so.
--full-indexInstead 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.
--binaryIn addition to --full-index, output a binary diff that can be applied with git-apply.
--abbrevInstead 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--break-rewritesBreak 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 resultin
-M--find-renamesDetect 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--find-copiesDetect 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-harderFor 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-deleteOmit 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.
-lThe -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
-OControl 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
--skip-to--rotate-toDiscard 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--no-relativeWhen 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--textTreat all files as text.
--ignore-cr-at-eolIgnore carriage-return at the end of line when doing a comparison.
--ignore-space-at-eolIgnore changes in whitespace at EOL.
-b--ignore-space-changeIgnore 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-spaceIgnore whitespace when comparing lines. This ignores differences even if one line has whitespace where the other line has none.
--ignore-blank-linesIgnore changes whose lines are all blank.
-I--ignore-matching-linesIgnore changes whose all lines match <regex>. This option may be specified more than once.
--inter-hunk-contextShow 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-contextShow 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-diffAllow 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-diffDisallow external diff drivers.
--textconv--no-textconvAllow (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-submodulesIgnore 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 tr
--src-prefixShow the given source prefix instead of "a/".
--dst-prefixShow the given destination prefix instead of "b/".
--no-prefixDo not show any source or destination prefix.
--default-prefixUse 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-prefixPrepend an additional prefix to every line of output.
--ita-invisible-in-indexBy 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.
-o--output-directoryUse <dir> to store the resulting files, instead of the current working directory.
-n--numberedName output in [PATCH n/m] format, even with a single patch.
-N--no-numberedName output in [PATCH] format.
--start-numberStart numbering the patches at <n> instead of 1.
--numbered-filesOutput file names will be a simple number sequence without the default first line of the commit appended.
-k--keep-subjectDo not strip/add [PATCH] from the first line of the commit log message.
-s--signoffAdd 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.
--stdoutPrint all commits to the standard output in mbox format, instead of creating a file for each one.
--attachCreate 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-attachDisable the creation of an attachment, overriding the configuration setting.
--inlineCreate 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--no-threadControls 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 e
--in-reply-toMake 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-upstreamDo 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.
--alwaysInclude patches for commits that do not introduce any change, which are omitted by default.
--cover-from-descriptionControls 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
--description-fileUse the contents of <file> instead of the branch’s description for generating the cover letter.
--subject-prefixInstead 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-lengthInstead 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.
--rfcPrepends 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 the rest of the <rfc> string
-v--reroll-countMark 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
--toAdd 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).
--ccAdd 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--fromUse 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 re
--add-headerAdd 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.
--encode-email-headers--no-encode-email-headersEncode 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.
--interdiffAs 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-diffAs 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=fe
--creation-factorUsed 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--no-notesAppend 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 con
--signature-fileWorks just like --signature except the signature is read from a file.
--suffixInstead 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--quietDo not print the names of the generated files to standard output.
--no-binaryDo 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-commitOutput an all-zero hash in each patch’s From header instead of the hash of the commit.
--rootTreat 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.
--progressShow progress reports on stderr as patches are generated.
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:
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.
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.
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:
One way to test if your MUA is set up correctly is:
$ 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.
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:
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.
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
mailnews.send_plaintext_flowed => false
mailnews.wraplength => 0
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.
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
$ git format-patch -k --stdout R1..R2 | git am -3 -k
$ git format-patch origin
For each commit a separate file is created in the current directory.
$ git format-patch --root origin
$ 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.
$ git format-patch -3