git/Documentation/git-check-ref-format.txt
Michael Haggerty a40e6fb67a Change check_refname_format() to reject unnormalized refnames
Since much of the infrastructure does not work correctly with
unnormalized refnames, change check_refname_format() to reject them.

Similarly, change "git check-ref-format" to reject unnormalized
refnames by default.  But add an option --normalize, which causes "git
check-ref-format" to normalize the refname before checking its format,
and print the normalized refname.  This is exactly the behavior of the
old --print option, which is retained but deprecated.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-05 13:45:30 -07:00

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git-check-ref-format(1)
=======================
NAME
----
git-check-ref-format - Ensures that a reference name is well formed
SYNOPSIS
--------
[verse]
'git check-ref-format' [--normalize]
[--[no-]allow-onelevel] [--refspec-pattern]
<refname>
'git check-ref-format' --branch <branchname-shorthand>
DESCRIPTION
-----------
Checks if a given 'refname' is acceptable, and exits with a non-zero
status if it is not.
A reference is used in git to specify branches and tags. A
branch head is stored in the `refs/heads` hierarchy, while
a tag is stored in the `refs/tags` hierarchy of the ref namespace
(typically in `$GIT_DIR/refs/heads` and `$GIT_DIR/refs/tags`
directories or, as entries in file `$GIT_DIR/packed-refs`
if refs are packed by `git gc`).
git imposes the following rules on how references are named:
. They can include slash `/` for hierarchical (directory)
grouping, but no slash-separated component can begin with a
dot `.` or end with the sequence `.lock`.
. They must contain at least one `/`. This enforces the presence of a
category like `heads/`, `tags/` etc. but the actual names are not
restricted. If the `--allow-onelevel` option is used, this rule
is waived.
. They cannot have two consecutive dots `..` anywhere.
. They cannot have ASCII control characters (i.e. bytes whose
values are lower than \040, or \177 `DEL`), space, tilde `~`,
caret `{caret}`, or colon `:` anywhere.
. They cannot have question-mark `?`, asterisk `{asterisk}`, or open
bracket `[` anywhere. See the `--refspec-pattern` option below for
an exception to this rule.
. They cannot begin or end with a slash `/` or contain multiple
consecutive slashes (see the `--normalize` option below for an
exception to this rule)
. They cannot end with a dot `.`.
. They cannot contain a sequence `@{`.
. They cannot contain a `\`.
These rules make it easy for shell script based tools to parse
reference names, pathname expansion by the shell when a reference name is used
unquoted (by mistake), and also avoids ambiguities in certain
reference name expressions (see linkgit:gitrevisions[7]):
. A double-dot `..` is often used as in `ref1..ref2`, and in some
contexts this notation means `{caret}ref1 ref2` (i.e. not in
`ref1` and in `ref2`).
. A tilde `~` and caret `{caret}` are used to introduce the postfix
'nth parent' and 'peel onion' operation.
. A colon `:` is used as in `srcref:dstref` to mean "use srcref\'s
value and store it in dstref" in fetch and push operations.
It may also be used to select a specific object such as with
'git cat-file': "git cat-file blob v1.3.3:refs.c".
. at-open-brace `@{` is used as a notation to access a reflog entry.
With the `--branch` option, it expands the ``previous branch syntax''
`@{-n}`. For example, `@{-1}` is a way to refer the last branch you
were on. This option should be used by porcelains to accept this
syntax anywhere a branch name is expected, so they can act as if you
typed the branch name.
OPTIONS
-------
--allow-onelevel::
--no-allow-onelevel::
Controls whether one-level refnames are accepted (i.e.,
refnames that do not contain multiple `/`-separated
components). The default is `--no-allow-onelevel`.
--refspec-pattern::
Interpret <refname> as a reference name pattern for a refspec
(as used with remote repositories). If this option is
enabled, <refname> is allowed to contain a single `{asterisk}`
in place of a one full pathname component (e.g.,
`foo/{asterisk}/bar` but not `foo/bar{asterisk}`).
--normalize::
Normalize 'refname' by removing any leading slash (`/`)
characters and collapsing runs of adjacent slashes between
name components into a single slash. Iff the normalized
refname is valid then print it to standard output and exit
with a status of 0. (`--print` is a deprecated way to spell
`--normalize`.)
EXAMPLES
--------
* Print the name of the previous branch:
+
------------
$ git check-ref-format --branch @{-1}
------------
* Determine the reference name to use for a new branch:
+
------------
$ ref=$(git check-ref-format --normalize "refs/heads/$newbranch") ||
die "we do not like '$newbranch' as a branch name."
------------
GIT
---
Part of the linkgit:git[1] suite