git-commit-vandalism/Documentation/git-for-each-ref.txt
Jeff King 0571979bd6 tag: do not show ambiguous tag names as "tags/foo"
Since b7cc53e9 (tag.c: use 'ref-filter' APIs, 2015-07-11),
git-tag has started showing tags with ambiguous names (i.e.,
when both "heads/foo" and "tags/foo" exists) as "tags/foo"
instead of just "foo". This is both:

  - pointless; the output of "git tag" includes only
    refs/tags, so we know that "foo" means the one in
    "refs/tags".

and

  - ambiguous; in the original output, we know that the line
    "foo" means that "refs/tags/foo" exists. In the new
    output, it is unclear whether we mean "refs/tags/foo" or
    "refs/tags/tags/foo".

The reason this happens is that commit b7cc53e9 switched
git-tag to use ref-filter's "%(refname:short)" output
formatting, which was adapted from for-each-ref. This more
general code does not know that we care only about tags, and
uses shorten_unambiguous_ref to get the short-name. We need
to tell it that we care only about "refs/tags/", and it
should shorten with respect to that value.

In theory, the ref-filter code could figure this out by us
passing FILTER_REFS_TAGS. But there are two complications
there:

  1. The handling of refname:short is deep in formatting
     code that does not even have our ref_filter struct, let
     alone the arguments to the filter_ref struct.

  2. In git v2.7.0, we expose the formatting language to the
     user. If we follow this path, it will mean that
     "%(refname:short)" behaves differently for "tag" versus
     "for-each-ref" (including "for-each-ref refs/tags/"),
     which can lead to confusion.

Instead, let's add a new modifier to the formatting
language, "strip", to remove a specific set of prefix
components. This fixes "git tag", and lets users invoke the
same behavior from their own custom formats (for "tag" or
"for-each-ref") while leaving ":short" with its same
consistent meaning in all places.

We introduce a test in t7004 for "git tag", which fails
without this patch. We also add a similar test in t3203 for
"git branch", which does not actually fail. But since it is
likely that "branch" will eventually use the same formatting
code, the test helps defend against future regressions.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-26 13:34:10 -08:00

269 lines
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git-for-each-ref(1)
===================
NAME
----
git-for-each-ref - Output information on each ref
SYNOPSIS
--------
[verse]
'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
[(--sort=<key>)...] [--format=<format>] [<pattern>...]
[--points-at <object>] [(--merged | --no-merged) [<object>]]
[--contains [<object>]]
DESCRIPTION
-----------
Iterate over all refs that match `<pattern>` and show them
according to the given `<format>`, after sorting them according
to the given set of `<key>`. If `<count>` is given, stop after
showing that many refs. The interpolated values in `<format>`
can optionally be quoted as string literals in the specified
host language allowing their direct evaluation in that language.
OPTIONS
-------
<count>::
By default the command shows all refs that match
`<pattern>`. This option makes it stop after showing
that many refs.
<key>::
A field name to sort on. Prefix `-` to sort in
descending order of the value. When unspecified,
`refname` is used. You may use the --sort=<key> option
multiple times, in which case the last key becomes the primary
key.
<format>::
A string that interpolates `%(fieldname)` from the
object pointed at by a ref being shown. If `fieldname`
is prefixed with an asterisk (`*`) and the ref points
at a tag object, the value for the field in the object
tag refers is used. When unspecified, defaults to
`%(objectname) SPC %(objecttype) TAB %(refname)`.
It also interpolates `%%` to `%`, and `%xx` where `xx`
are hex digits interpolates to character with hex code
`xx`; for example `%00` interpolates to `\0` (NUL),
`%09` to `\t` (TAB) and `%0a` to `\n` (LF).
<pattern>...::
If one or more patterns are given, only refs are shown that
match against at least one pattern, either using fnmatch(3) or
literally, in the latter case matching completely or from the
beginning up to a slash.
--shell::
--perl::
--python::
--tcl::
If given, strings that substitute `%(fieldname)`
placeholders are quoted as string literals suitable for
the specified host language. This is meant to produce
a scriptlet that can directly be `eval`ed.
--points-at <object>::
Only list refs which points at the given object.
--merged [<object>]::
Only list refs whose tips are reachable from the
specified commit (HEAD if not specified).
--no-merged [<object>]::
Only list refs whose tips are not reachable from the
specified commit (HEAD if not specified).
--contains [<object>]::
Only list tags which contain the specified commit (HEAD if not
specified).
FIELD NAMES
-----------
Various values from structured fields in referenced objects can
be used to interpolate into the resulting output, or as sort
keys.
For all objects, the following names can be used:
refname::
The name of the ref (the part after $GIT_DIR/).
For a non-ambiguous short name of the ref append `:short`.
The option core.warnAmbiguousRefs is used to select the strict
abbreviation mode. If `strip=<N>` is appended, strips `<N>`
slash-separated path components from the front of the refname
(e.g., `%(refname:strip=2)` turns `refs/tags/foo` into `foo`.
`<N>` must be a positive integer. If a displayed ref has fewer
components than `<N>`, the command aborts with an error.
objecttype::
The type of the object (`blob`, `tree`, `commit`, `tag`).
objectsize::
The size of the object (the same as 'git cat-file -s' reports).
objectname::
The object name (aka SHA-1).
For a non-ambiguous abbreviation of the object name append `:short`.
upstream::
The name of a local ref which can be considered ``upstream''
from the displayed ref. Respects `:short` in the same way as
`refname` above. Additionally respects `:track` to show
"[ahead N, behind M]" and `:trackshort` to show the terse
version: ">" (ahead), "<" (behind), "<>" (ahead and behind),
or "=" (in sync). Has no effect if the ref does not have
tracking information associated with it.
push::
The name of a local ref which represents the `@{push}` location
for the displayed ref. Respects `:short`, `:track`, and
`:trackshort` options as `upstream` does. Produces an empty
string if no `@{push}` ref is configured.
HEAD::
'*' if HEAD matches current ref (the checked out branch), ' '
otherwise.
color::
Change output color. Followed by `:<colorname>`, where names
are described in `color.branch.*`.
align::
Left-, middle-, or right-align the content between
%(align:...) and %(end). The "align:" is followed by `<width>`
and `<position>` in any order separated by a comma, where the
`<position>` is either left, right or middle, default being
left and `<width>` is the total length of the content with
alignment. If the contents length is more than the width then
no alignment is performed. If used with '--quote' everything
in between %(align:...) and %(end) is quoted, but if nested
then only the topmost level performs quoting.
In addition to the above, for commit and tag objects, the header
field names (`tree`, `parent`, `object`, `type`, and `tag`) can
be used to specify the value in the header field.
Fields that have name-email-date tuple as its value (`author`,
`committer`, and `tagger`) can be suffixed with `name`, `email`,
and `date` to extract the named component.
The complete message in a commit and tag object is `contents`.
Its first line is `contents:subject`, where subject is the concatenation
of all lines of the commit message up to the first blank line. The next
line is 'contents:body', where body is all of the lines after the first
blank line. The optional GPG signature is `contents:signature`. The
first `N` lines of the message is obtained using `contents:lines=N`.
For sorting purposes, fields with numeric values sort in numeric
order (`objectsize`, `authordate`, `committerdate`, `taggerdate`).
All other fields are used to sort in their byte-value order.
There is also an option to sort by versions, this can be done by using
the fieldname `version:refname` or its alias `v:refname`.
In any case, a field name that refers to a field inapplicable to
the object referred by the ref does not cause an error. It
returns an empty string instead.
As a special case for the date-type fields, you may specify a format for
the date by adding `:` followed by date format name (see the
values the `--date` option to linkgit::git-rev-list[1] takes).
EXAMPLES
--------
An example directly producing formatted text. Show the most recent
3 tagged commits:
------------
#!/bin/sh
git for-each-ref --count=3 --sort='-*authordate' \
--format='From: %(*authorname) %(*authoremail)
Subject: %(*subject)
Date: %(*authordate)
Ref: %(*refname)
%(*body)
' 'refs/tags'
------------
A simple example showing the use of shell eval on the output,
demonstrating the use of --shell. List the prefixes of all heads:
------------
#!/bin/sh
git for-each-ref --shell --format="ref=%(refname)" refs/heads | \
while read entry
do
eval "$entry"
echo `dirname $ref`
done
------------
A bit more elaborate report on tags, demonstrating that the format
may be an entire script:
------------
#!/bin/sh
fmt='
r=%(refname)
t=%(*objecttype)
T=${r#refs/tags/}
o=%(*objectname)
n=%(*authorname)
e=%(*authoremail)
s=%(*subject)
d=%(*authordate)
b=%(*body)
kind=Tag
if test "z$t" = z
then
# could be a lightweight tag
t=%(objecttype)
kind="Lightweight tag"
o=%(objectname)
n=%(authorname)
e=%(authoremail)
s=%(subject)
d=%(authordate)
b=%(body)
fi
echo "$kind $T points at a $t object $o"
if test "z$t" = zcommit
then
echo "The commit was authored by $n $e
at $d, and titled
$s
Its message reads as:
"
echo "$b" | sed -e "s/^/ /"
echo
fi
'
eval=`git for-each-ref --shell --format="$fmt" \
--sort='*objecttype' \
--sort=-taggerdate \
refs/tags`
eval "$eval"
------------
SEE ALSO
--------
linkgit:git-show-ref[1]
GIT
---
Part of the linkgit:git[1] suite