-------
Certain operations by git can be influenced by assigning
-particular attributes to a path. Currently, three operations
-are attributes-aware.
+particular attributes to a path. Currently, the following
+operations are attributes-aware.
Checking-out and checking-in
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^
When the attribute `ident` is set to a path, git replaces
-`$ident$` in the blob object with `$ident:`, followed by
+`$Id$` in the blob object with `$Id:`, followed by
40-character hexadecimal blob object name, followed by a dollar
sign `$` upon checkout. Any byte sequence that begins with
-`$ident:` and ends with `$` in the worktree file is replaced
-with `$ident$` upon check-in.
-
-
-Interaction between checkin/checkout attributes
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-In the check-in codepath, the worktree file is first converted
-with `ident` (if specified), and then with `crlf` (again, if
-specified and applicable).
-
-In the check-out codepath, the blob content is first converted
-with `crlf`, and then `ident`.
+`$Id:` and ends with `$` in the worktree file is replaced
+with `$Id$` upon check-in.
`filter`
^^^^^^^^
-A `filter` attribute can be set to a string value. This names
+A `filter` attribute can be set to a string value that names a
filter driver specified in the configuration.
-A filter driver consists of `clean` command and `smudge`
+A filter driver consists of a `clean` command and a `smudge`
command, either of which can be left unspecified. Upon
-checkout, when `smudge` command is specified, the command is fed
-the blob object from its standard input, and its standard output
-is used to update the worktree file. Similarly, `clean` command
-is used to convert the contents of worktree file upon checkin.
+checkout, when the `smudge` command is specified, the command is
+fed the blob object from its standard input, and its standard
+output is used to update the worktree file. Similarly, the
+`clean` command is used to convert the contents of worktree file
+upon checkin.
-Missing filter driver definition in the config is not an error
+A missing filter driver definition in the config is not an error
but makes the filter a no-op passthru.
The content filtering is done to massage the content into a
shape that is more convenient for the platform, filesystem, and
-the user to use. The keyword here is "more convenient" and not
-"turning something unusable into usable". In other words, it is
-"hanging yourself because we gave you a long rope" if your
-project uses filtering mechanism in such a way that it makes
-your project unusable unless the checkout is done with a
-specific filter in effect.
+the user to use. The key phrase here is "more convenient" and not
+"turning something unusable into usable". In other words, the
+intent is that if someone unsets the filter driver definition,
+or does not have the appropriate filter program, the project
+should still be usable.
Interaction between checkin/checkout attributes
~~~~~~~~~~~~~~~~~~~~
The attribute `diff` affects if `git diff` generates textual
-patch for the path or just says `Binary files differ`.
+patch for the path or just says `Binary files differ`. It also
+can affect what line is shown on the hunk header `@@ -k,l +n,m @@`
+line.
Set::
Diff is shown using the specified custom diff driver.
The driver program is given its input using the same
calling convention as used for GIT_EXTERNAL_DIFF
- program.
+ program. This name is also used for custom hunk header
+ selection.
Defining a custom diff driver
attribute set to `jcdiff`, it calls the command you specified
with the above configuration, i.e. `j-c-diff`, with 7
parameters, just like `GIT_EXTERNAL_DIFF` program is called.
-See gitlink:git[7] for details.
+See linkgit:git[7] for details.
+
+
+Defining a custom hunk-header
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Each group of changes (called "hunk") in the textual diff output
+is prefixed with a line of the form:
+
+ @@ -k,l +n,m @@ TEXT
+
+The text is called 'hunk header', and by default a line that
+begins with an alphabet, an underscore or a dollar sign is used,
+which matches what GNU `diff -p` output uses. This default
+selection however is not suited for some contents, and you can
+use customized pattern to make a selection.
+
+First in .gitattributes, you would assign the `diff` attribute
+for paths.
+
+------------------------
+*.tex diff=tex
+------------------------
+
+Then, you would define "diff.tex.funcname" configuration to
+specify a regular expression that matches a line that you would
+want to appear as the hunk header, like this:
+
+------------------------
+[diff "tex"]
+ funcname = "^\\(\\\\\\(sub\\)*section{.*\\)$"
+------------------------
+
+Note. A single level of backslashes are eaten by the
+configuration file parser, so you would need to double the
+backslashes; the pattern above picks a line that begins with a
+backslash, and zero or more occurrences of `sub` followed by
+`section` followed by open brace, to the end of line.
+
+There are a few built-in patterns to make this easier, and `tex`
+is one of them, so you do not have to write the above in your
+configuration file (you still need to enable this with the
+attribute mechanism, via `.gitattributes`). Another built-in
+pattern is defined for `java` that defines a pattern suitable
+for program text in Java language.
Performing a three-way merge
requested with "binary".
+Built-in merge drivers
+^^^^^^^^^^^^^^^^^^^^^^
+
+There are a few built-in low-level merge drivers defined that
+can be asked for via the `merge` attribute.
+
+text::
+
+ Usual 3-way file level merge for text files. Conflicted
+ regions are marked with conflict markers `<<<<<<<`,
+ `=======` and `>>>>>>>`. The version from your branch
+ appears before the `=======` marker, and the version
+ from the merged branch appears after the `=======`
+ marker.
+
+binary::
+
+ Keep the version from your branch in the work tree, but
+ leave the path in the conflicted state for the user to
+ sort out.
+
+union::
+
+ Run 3-way file level merge for text files, but take
+ lines from both versions, instead of leaving conflict
+ markers. This tends to leave the added lines in the
+ resulting file in random order and the user should
+ verify the result. Do not use this if you do not
+ understand the implications.
+
+
Defining a custom merge driver
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The definition of a merge driver is done in `gitconfig` not
-`gitattributes` file, so strictly speaking this manual page is a
-wrong place to talk about it. However...
+The definition of a merge driver is done in the `.git/config`
+file, not in the `gitattributes` file, so strictly speaking this
+manual page is a wrong place to talk about it. However...
To define a custom merge driver `filfre`, add a section to your
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
internal merge and the final merge.
+Checking whitespace errors
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`whitespace`
+^^^^^^^^^^^^
+
+The `core.whitespace` configuration variable allows you to define what
+`diff` and `apply` should consider whitespace errors for all paths in
+the project (See linkgit:git-config[1]). This attribute gives you finer
+control per path.
+
+Set::
+
+ Notice all types of potential whitespace errors known to git.
+
+Unset::
+
+ Do not notice anything as error.
+
+Unspecified::
+
+ Use the value of `core.whitespace` configuration variable to
+ decide what to notice as error.
+
+String::
+
+ Specify a comma separate list of common whitespace problems to
+ notice in the same format as `core.whitespace` configuration
+ variable.
+
+
EXAMPLE
-------
the attributes given to path `t/abc` are computed as follows:
1. By examining `t/.gitattributes` (which is in the same
- diretory as the path in question), git finds that the first
+ directory as the path in question), git finds that the first
line matches. `merge` attribute is set. It also finds that
the second line matches, and attributes `foo` and `bar`
are unset.
and `bar` attributes should be given to this path, so it
leaves `foo` and `bar` unset. Attribute `baz` is set.
-3. Finally it examines `$GIT_DIR/info/gitattributes`. This file
+3. Finally it examines `$GIT_DIR/info/attributes`. This file
is used to override the in-tree settings. The first line is
a match, and `foo` is set, `bar` is reverted to unspecified
state, and `baz` is unset.
-As the result, the attributes assignement to `t/abc` becomes:
+As the result, the attributes assignment to `t/abc` becomes:
----------------------------------------------------------------
foo set to true
----------------------------------------------------------------
+Creating an archive
+~~~~~~~~~~~~~~~~~~~
+
+`export-subst`
+^^^^^^^^^^^^^^
+
+If the attribute `export-subst` is set for a file then git will expand
+several placeholders when adding this file to an archive. The
+expansion depends on the availability of a commit ID, i.e. if
+linkgit:git-archive[1] has been given a tree instead of a commit or a
+tag then no replacement will be done. The placeholders are the same
+as those for the option `--pretty=format:` of linkgit:git-log[1],
+except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
+in the file. E.g. the string `$Format:%H$` will be replaced by the
+commit hash.
+
+
GIT
---
-Part of the gitlink:git[7] suite
+Part of the linkgit:git[7] suite