git/Documentation/git-check-ref-format.txt
Jeff King 6cf378f0cb docs: stop using asciidoc no-inline-literal
In asciidoc 7, backticks like `foo` produced a typographic
effect, but did not otherwise affect the syntax. In asciidoc
8, backticks introduce an "inline literal" inside which markup
is not interpreted. To keep compatibility with existing
documents, asciidoc 8 has a "no-inline-literal" attribute to
keep the old behavior. We enabled this so that the
documentation could be built on either version.

It has been several years now, and asciidoc 7 is no longer
in wide use. We can now decide whether or not we want
inline literals on their own merits, which are:

  1. The source is much easier to read when the literal
     contains punctuation. You can use `master~1` instead
     of `master{tilde}1`.

  2. They are less error-prone. Because of point (1), we
     tend to make mistakes and forget the extra layer of
     quoting.

This patch removes the no-inline-literal attribute from the
Makefile and converts every use of backticks in the
documentation to an inline literal (they must be cleaned up,
or the example above would literally show "{tilde}" in the
output).

Problematic sites were found by grepping for '`.*[{\\]' and
examined and fixed manually. The results were then verified
by comparing the output of "html2text" on the set of
generated html pages. Doing so revealed that in addition to
making the source more readable, this patch fixes several
formatting bugs:

  - HTML rendering used the ellipsis character instead of
    literal "..." in code examples (like "git log A...B")

  - some code examples used the right-arrow character
    instead of '->' because they failed to quote

  - api-config.txt did not quote tilde, and the resulting
    HTML contained a bogus snippet like:

      <tt><sub></tt> foo <tt></sub>bar</tt>

    which caused some parsers to choke and omit whole
    sections of the page.

  - git-commit.txt confused ``foo`` (backticks inside a
    literal) with ``foo'' (matched double-quotes)

  - mentions of `A U Thor <author@example.com>` used to
    erroneously auto-generate a mailto footnote for
    author@example.com

  - the description of --word-diff=plain incorrectly showed
    the output as "[-removed-] and {added}", not "{+added+}".

  - using "prime" notation like:

      commit `C` and its replacement `C'`

    confused asciidoc into thinking that everything between
    the first backtick and the final apostrophe were meant
    to be inside matched quotes

  - asciidoc got confused by the escaping of some of our
    asterisks. In particular,

      `credential.\*` and `credential.<url>.\*`

    properly escaped the asterisk in the first case, but
    literally passed through the backslash in the second
    case.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-26 13:19:06 -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 `^`, or colon `:` anywhere.
. They cannot have question-mark `?`, 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 `^ref1 ref2` (i.e. not in
`ref1` and in `ref2`).
. A tilde `~` and 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 `*`
in place of a one full pathname component (e.g.,
`foo/*/bar` but not `foo/bar*`).
--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