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diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt new file mode 100644 index 0000000..418265f --- /dev/null +++ b/Documentation/git-interpret-trailers.txt @@ -0,0 +1,523 @@ +git-interpret-trailers(1) +========================= + +NAME +---- +git-interpret-trailers - Add or parse structured information in commit messages + +SYNOPSIS +-------- +[verse] +'git interpret-trailers' [--in-place] [--trim-empty] + [(--trailer (<key>|<keyAlias>)[(=|:)<value>])...] + [--parse] [<file>...] + +DESCRIPTION +----------- +Add or parse 'trailer' lines that look similar to RFC 822 e-mail +headers, at the end of the otherwise free-form part of a commit +message. For example, in the following commit message + +------------------------------------------------ +subject + +Lorem ipsum dolor sit amet, consectetur adipiscing elit. + +Signed-off-by: Alice <alice@example.com> +Signed-off-by: Bob <bob@example.com> +------------------------------------------------ + +the last two lines starting with "Signed-off-by" are trailers. + +This command reads commit messages from either the +<file> arguments or the standard input if no <file> is specified. +If `--parse` is specified, the output consists of the parsed trailers +coming from the input, without influencing them with any command line +options or configuration variables. + +Otherwise, this command applies `trailer.*` configuration variables +(which could potentially add new trailers, as well as reposition them), +as well as any command line arguments that can override configuration +variables (such as `--trailer=...` which could also add new trailers), +to each input file. The result is emitted on the standard output. + +This command can also operate on the output of linkgit:git-format-patch[1], +which is more elaborate than a plain commit message. Namely, such output +includes a commit message (as above), a "---" divider line, and a patch part. +For these inputs, the divider and patch parts are not modified by +this command and are emitted as is on the output, unless +`--no-divider` is specified. + +Some configuration variables control the way the `--trailer` arguments +are applied to each input and the way any existing trailer in +the input is changed. They also make it possible to +automatically add some trailers. + +By default, a '<key>=<value>' or '<key>:<value>' argument given +using `--trailer` will be appended after the existing trailers only if +the last trailer has a different (<key>, <value>) pair (or if there +is no existing trailer). The <key> and <value> parts will be trimmed +to remove starting and trailing whitespace, and the resulting trimmed +<key> and <value> will appear in the output like this: + +------------------------------------------------ +key: value +------------------------------------------------ + +This means that the trimmed <key> and <value> will be separated by +`': '` (one colon followed by one space). + +For convenience, a <keyAlias> can be configured to make using `--trailer` +shorter to type on the command line. This can be configured using the +'trailer.<keyAlias>.key' configuration variable. The <keyAlias> must be a prefix +of the full <key> string, although case sensitivity does not matter. For +example, if you have + +------------------------------------------------ +trailer.sign.key "Signed-off-by: " +------------------------------------------------ + +in your configuration, you only need to specify `--trailer="sign: foo"` +on the command line instead of `--trailer="Signed-off-by: foo"`. + +By default the new trailer will appear at the end of all the existing +trailers. If there is no existing trailer, the new trailer will appear +at the end of the input. A blank line will be added before the new +trailer if there isn't one already. + +Existing trailers are extracted from the input by looking for +a group of one or more lines that (i) is all trailers, or (ii) contains at +least one Git-generated or user-configured trailer and consists of at +least 25% trailers. +The group must be preceded by one or more empty (or whitespace-only) lines. +The group must either be at the end of the input or be the last +non-whitespace lines before a line that starts with '---' (followed by a +space or the end of the line). + +When reading trailers, there can be no whitespace before or inside the +<key>, but any number of regular space and tab characters are allowed +between the <key> and the separator. There can be whitespaces before, +inside or after the <value>. The <value> may be split over multiple lines +with each subsequent line starting with at least one whitespace, like +the "folding" in RFC 822. Example: + +------------------------------------------------ +key: This is a very long value, with spaces and + newlines in it. +------------------------------------------------ + +Note that trailers do not follow (nor are they intended to follow) many of the +rules for RFC 822 headers. For example they do not follow the encoding rule. + +OPTIONS +------- +--in-place:: + Edit the files in place. + +--trim-empty:: + If the <value> part of any trailer contains only whitespace, + the whole trailer will be removed from the output. + This applies to existing trailers as well as new trailers. + +--trailer <key>[(=|:)<value>]:: + Specify a (<key>, <value>) pair that should be applied as a + trailer to the inputs. See the description of this + command. + +--where <placement>:: +--no-where:: + Specify where all new trailers will be added. A setting + provided with '--where' overrides the `trailer.where` and any + applicable `trailer.<keyAlias>.where` configuration variables + and applies to all '--trailer' options until the next occurrence of + '--where' or '--no-where'. Upon encountering '--no-where', clear the + effect of any previous use of '--where', such that the relevant configuration + variables are no longer overridden. Possible placements are `after`, + `before`, `end` or `start`. + +--if-exists <action>:: +--no-if-exists:: + Specify what action will be performed when there is already at + least one trailer with the same <key> in the input. A setting + provided with '--if-exists' overrides the `trailer.ifExists` and any + applicable `trailer.<keyAlias>.ifExists` configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-exists' or '--no-if-exists'. Upon encountering '--no-if-exists, clear the + effect of any previous use of '--if-exists, such that the relevant configuration + variables are no longer overridden. Possible actions are `addIfDifferent`, + `addIfDifferentNeighbor`, `add`, `replace` and `doNothing`. + +--if-missing <action>:: +--no-if-missing:: + Specify what action will be performed when there is no other + trailer with the same <key> in the input. A setting + provided with '--if-missing' overrides the `trailer.ifMissing` and any + applicable `trailer.<keyAlias>.ifMissing` configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-missing' or '--no-if-missing'. Upon encountering '--no-if-missing, + clear the effect of any previous use of '--if-missing, such that the relevant + configuration variables are no longer overridden. Possible actions are `doNothing` + or `add`. + +--only-trailers:: + Output only the trailers, not any other parts of the input. + +--only-input:: + Output only trailers that exist in the input; do not add any + from the command-line or by applying `trailer.*` configuration + variables. + +--unfold:: + If a trailer has a value that runs over multiple lines (aka "folded"), + reformat the value into a single line. + +--parse:: + A convenience alias for `--only-trailers --only-input + --unfold`. This makes it easier to only see the trailers coming from the + input without influencing them with any command line options or + configuration variables, while also making the output machine-friendly with + --unfold. + +--no-divider:: + Do not treat `---` as the end of the commit message. Use this + when you know your input contains just the commit message itself + (and not an email or the output of `git format-patch`). + +CONFIGURATION VARIABLES +----------------------- + +trailer.separators:: + This option tells which characters are recognized as trailer + separators. By default only ':' is recognized as a trailer + separator, except that '=' is always accepted on the command + line for compatibility with other git commands. ++ +The first character given by this option will be the default character +used when another separator is not specified in the config for this +trailer. ++ +For example, if the value for this option is "%=$", then only lines +using the format '<key><sep><value>' with <sep> containing '%', '=' +or '$' and then spaces will be considered trailers. And '%' will be +the default separator used, so by default trailers will appear like: +'<key>% <value>' (one percent sign and one space will appear between +the key and the value). + +trailer.where:: + This option tells where a new trailer will be added. ++ +This can be `end`, which is the default, `start`, `after` or `before`. ++ +If it is `end`, then each new trailer will appear at the end of the +existing trailers. ++ +If it is `start`, then each new trailer will appear at the start, +instead of the end, of the existing trailers. ++ +If it is `after`, then each new trailer will appear just after the +last trailer with the same <key>. ++ +If it is `before`, then each new trailer will appear just before the +first trailer with the same <key>. + +trailer.ifexists:: + This option makes it possible to choose what action will be + performed when there is already at least one trailer with the + same <key> in the input. ++ +The valid values for this option are: `addIfDifferentNeighbor` (this +is the default), `addIfDifferent`, `add`, `replace` or `doNothing`. ++ +With `addIfDifferentNeighbor`, a new trailer will be added only if no +trailer with the same (<key>, <value>) pair is above or below the line +where the new trailer will be added. ++ +With `addIfDifferent`, a new trailer will be added only if no trailer +with the same (<key>, <value>) pair is already in the input. ++ +With `add`, a new trailer will be added, even if some trailers with +the same (<key>, <value>) pair are already in the input. ++ +With `replace`, an existing trailer with the same <key> will be +deleted and the new trailer will be added. The deleted trailer will be +the closest one (with the same <key>) to the place where the new one +will be added. ++ +With `doNothing`, nothing will be done; that is no new trailer will be +added if there is already one with the same <key> in the input. + +trailer.ifmissing:: + This option makes it possible to choose what action will be + performed when there is not yet any trailer with the same + <key> in the input. ++ +The valid values for this option are: `add` (this is the default) and +`doNothing`. ++ +With `add`, a new trailer will be added. ++ +With `doNothing`, nothing will be done. + +trailer.<keyAlias>.key:: + Defines a <keyAlias> for the <key>. The <keyAlias> must be a + prefix (case does not matter) of the <key>. For example, in `git + config trailer.ack.key "Acked-by"` the "Acked-by" is the <key> and + the "ack" is the <keyAlias>. This configuration allows the shorter + `--trailer "ack:..."` invocation on the command line using the "ack" + <keyAlias> instead of the longer `--trailer "Acked-by:..."`. ++ +At the end of the <key>, a separator can appear and then some +space characters. By default the only valid separator is ':', +but this can be changed using the `trailer.separators` config +variable. ++ +If there is a separator in the key, then it overrides the default +separator when adding the trailer. + +trailer.<keyAlias>.where:: + This option takes the same values as the 'trailer.where' + configuration variable and it overrides what is specified by + that option for trailers with the specified <keyAlias>. + +trailer.<keyAlias>.ifexists:: + This option takes the same values as the 'trailer.ifexists' + configuration variable and it overrides what is specified by + that option for trailers with the specified <keyAlias>. + +trailer.<keyAlias>.ifmissing:: + This option takes the same values as the 'trailer.ifmissing' + configuration variable and it overrides what is specified by + that option for trailers with the specified <keyAlias>. + +trailer.<keyAlias>.command:: + Deprecated in favor of 'trailer.<keyAlias>.cmd'. + This option behaves in the same way as 'trailer.<keyAlias>.cmd', except + that it doesn't pass anything as argument to the specified command. + Instead the first occurrence of substring $ARG is replaced by the + <value> that would be passed as argument. ++ +Note that $ARG in the user's command is +only replaced once and that the original way of replacing $ARG is not safe. ++ +When both 'trailer.<keyAlias>.cmd' and 'trailer.<keyAlias>.command' are given +for the same <keyAlias>, 'trailer.<keyAlias>.cmd' is used and +'trailer.<keyAlias>.command' is ignored. + +trailer.<keyAlias>.cmd:: + This option can be used to specify a shell command that will be called + once to automatically add a trailer with the specified <keyAlias>, and then + called each time a '--trailer <keyAlias>=<value>' argument is specified to + modify the <value> of the trailer that this option would produce. ++ +When the specified command is first called to add a trailer +with the specified <keyAlias>, the behavior is as if a special +'--trailer <keyAlias>=<value>' argument was added at the beginning +of the "git interpret-trailers" command, where <value> +is taken to be the standard output of the command with any +leading and trailing whitespace trimmed off. ++ +If some '--trailer <keyAlias>=<value>' arguments are also passed +on the command line, the command is called again once for each +of these arguments with the same <keyAlias>. And the <value> part +of these arguments, if any, will be passed to the command as its +first argument. This way the command can produce a <value> computed +from the <value> passed in the '--trailer <keyAlias>=<value>' argument. + +EXAMPLES +-------- + +* Configure a 'sign' trailer with a 'Signed-off-by' key, and then + add two of these trailers to a commit message file: ++ +------------ +$ git config trailer.sign.key "Signed-off-by" +$ cat msg.txt +subject + +body text +$ git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>' <msg.txt +subject + +body text + +Signed-off-by: Alice <alice@example.com> +Signed-off-by: Bob <bob@example.com> +------------ + +* Use the `--in-place` option to edit a commit message file in place: ++ +------------ +$ cat msg.txt +subject + +body text + +Signed-off-by: Bob <bob@example.com> +$ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt +$ cat msg.txt +subject + +body text + +Signed-off-by: Bob <bob@example.com> +Acked-by: Alice <alice@example.com> +------------ + +* Extract the last commit as a patch, and add a 'Cc' and a + 'Reviewed-by' trailer to it: ++ +------------ +$ git format-patch -1 +0001-foo.patch +$ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch +------------ + +* Configure a 'sign' trailer with a command to automatically add a + 'Signed-off-by: ' with the author information only if there is no + 'Signed-off-by: ' already, and show how it works: ++ +------------ +$ cat msg1.txt +subject + +body text +$ git config trailer.sign.key "Signed-off-by: " +$ git config trailer.sign.ifmissing add +$ git config trailer.sign.ifexists doNothing +$ git config trailer.sign.cmd 'echo "$(git config user.name) <$(git config user.email)>"' +$ git interpret-trailers --trailer sign <msg1.txt +subject + +body text + +Signed-off-by: Bob <bob@example.com> +$ cat msg2.txt +subject + +body text + +Signed-off-by: Alice <alice@example.com> +$ git interpret-trailers --trailer sign <msg2.txt +subject + +body text + +Signed-off-by: Alice <alice@example.com> +------------ + +* Configure a 'fix' trailer with a key that contains a '#' and no + space after this character, and show how it works: ++ +------------ +$ git config trailer.separators ":#" +$ git config trailer.fix.key "Fix #" +$ echo "subject" | git interpret-trailers --trailer fix=42 +subject + +Fix #42 +------------ + +* Configure a 'help' trailer with a cmd use a script `glog-find-author` + which search specified author identity from git log in git repository + and show how it works: ++ +------------ +$ cat ~/bin/glog-find-author +#!/bin/sh +test -n "$1" && git log --author="$1" --pretty="%an <%ae>" -1 || true +$ cat msg.txt +subject + +body text +$ git config trailer.help.key "Helped-by: " +$ git config trailer.help.ifExists "addIfDifferentNeighbor" +$ git config trailer.help.cmd "~/bin/glog-find-author" +$ git interpret-trailers --trailer="help:Junio" --trailer="help:Couder" <msg.txt +subject + +body text + +Helped-by: Junio C Hamano <gitster@pobox.com> +Helped-by: Christian Couder <christian.couder@gmail.com> +------------ + +* Configure a 'ref' trailer with a cmd use a script `glog-grep` + to grep last relevant commit from git log in the git repository + and show how it works: ++ +------------ +$ cat ~/bin/glog-grep +#!/bin/sh +test -n "$1" && git log --grep "$1" --pretty=reference -1 || true +$ cat msg.txt +subject + +body text +$ git config trailer.ref.key "Reference-to: " +$ git config trailer.ref.ifExists "replace" +$ git config trailer.ref.cmd "~/bin/glog-grep" +$ git interpret-trailers --trailer="ref:Add copyright notices." <msg.txt +subject + +body text + +Reference-to: 8bc9a0c769 (Add copyright notices., 2005-04-07) +------------ + +* Configure a 'see' trailer with a command to show the subject of a + commit that is related, and show how it works: ++ +------------ +$ cat msg.txt +subject + +body text + +see: HEAD~2 +$ cat ~/bin/glog-ref +#!/bin/sh +git log -1 --oneline --format="%h (%s)" --abbrev-commit --abbrev=14 +$ git config trailer.see.key "See-also: " +$ git config trailer.see.ifExists "replace" +$ git config trailer.see.ifMissing "doNothing" +$ git config trailer.see.cmd "glog-ref" +$ git interpret-trailers --trailer=see <msg.txt +subject + +body text + +See-also: fe3187489d69c4 (subject of related commit) +------------ + +* Configure a commit template with some trailers with empty values + (using sed to show and keep the trailing spaces at the end of the + trailers), then configure a commit-msg hook that uses + 'git interpret-trailers' to remove trailers with empty values and + to add a 'git-version' trailer: ++ +------------ +$ cat temp.txt +***subject*** + +***message*** + +Fixes: Z +Cc: Z +Reviewed-by: Z +Signed-off-by: Z +$ sed -e 's/ Z$/ /' temp.txt > commit_template.txt +$ git config commit.template commit_template.txt +$ cat .git/hooks/commit-msg +#!/bin/sh +git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new" +mv "\$1.new" "\$1" +$ chmod +x .git/hooks/commit-msg +------------ + +SEE ALSO +-------- +linkgit:git-commit[1], linkgit:git-format-patch[1], linkgit:git-config[1] + +GIT +--- +Part of the linkgit:git[1] suite |