diff options
Diffstat (limited to 'Documentation/gitattributes.txt')
| -rw-r--r-- | Documentation/gitattributes.txt | 143 |
1 files changed, 133 insertions, 10 deletions
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 564586b943..412c55b549 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -62,14 +62,21 @@ consults `$GIT_DIR/info/attributes` file (which has the highest precedence), `.gitattributes` file in the same directory as the path in question, and its parent directories up to the toplevel of the work tree (the further the directory that contains `.gitattributes` -is from the path in question, the lower its precedence). +is from the path in question, the lower its precedence). Finally +global and system-wide files are considered (they have the lowest +precedence). If you wish to affect only a single repository (i.e., to assign -attributes to files that are particular to one user's workflow), then +attributes to files that are particular to +one user's workflow for that repository), then attributes should be placed in the `$GIT_DIR/info/attributes` file. Attributes which should be version-controlled and distributed to other repositories (i.e., attributes of interest to all users) should go into -`.gitattributes` files. +`.gitattributes` files. Attributes that should affect all repositories +for a single user should be placed in a file specified by the +`core.attributesfile` configuration option (see linkgit:git-config[1]). +Attributes for all users on a system should be placed in the +`$(prefix)/etc/gitattributes` file. Sometimes you would need to override an setting of an attribute for a path to `unspecified` state. This can be done by listing @@ -317,6 +324,27 @@ command is "cat"). smudge = cat ------------------------ +For best results, `clean` should not alter its output further if it is +run twice ("clean->clean" should be equivalent to "clean"), and +multiple `smudge` commands should not alter `clean`'s output +("smudge->smudge->clean" should be equivalent to "clean"). See the +section on merging below. + +The "indent" filter is well-behaved in this regard: it will not modify +input that is already correctly indented. In this case, the lack of a +smudge filter means that the clean filter _must_ accept its own output +without modifying it. + +Sequence "%f" on the filter command line is replaced with the name of +the file the filter is working on. A filter might use this in keyword +substitution. For example: + +------------------------ +[filter "p4"] + clean = git-p4-filter --clean %f + smudge = git-p4-filter --smudge %f +------------------------ + Interaction between checkin/checkout attributes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -331,6 +359,29 @@ In the check-out codepath, the blob content is first converted with `text`, and then `ident` and fed to `filter`. +Merging branches with differing checkin/checkout attributes +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +If you have added attributes to a file that cause the canonical +repository format for that file to change, such as adding a +clean/smudge filter or text/eol/ident attributes, merging anything +where the attribute is not in place would normally cause merge +conflicts. + +To prevent these unnecessary merge conflicts, git can be told to run a +virtual check-out and check-in of all three stages of a file when +resolving a three-way merge by setting the `merge.renormalize` +configuration variable. This prevents changes caused by check-in +conversion from causing spurious merge conflicts when a converted file +is merged with an unconverted file. + +As long as a "smudge->clean" results in the same output as a "clean" +even on files that are already smudged, this strategy will +automatically resolve all filter-related conflicts. Filters that do +not act in this way may cause additional merge conflicts that must be +resolved manually. + + Generating diff text ~~~~~~~~~~~~~~~~~~~~ @@ -441,6 +492,10 @@ patterns are available: - `cpp` suitable for source code in the C and C++ languages. +- `csharp` suitable for source code in the C# language. + +- `fortran` suitable for source code in the Fortran language. + - `html` suitable for HTML/XHTML documents. - `java` suitable for source code in the Java language. @@ -449,6 +504,8 @@ patterns are available: - `pascal` suitable for source code in the Pascal/Delphi language. +- `perl` suitable for source code in the Perl language. + - `php` suitable for source code in the PHP language. - `python` suitable for source code in the Python language. @@ -536,13 +593,77 @@ and now produces better output), you can remove the cache manually with `git update-ref -d refs/notes/textconv/jpg` (where "jpg" is the name of the diff driver, as in the example above). +Choosing textconv versus external diff +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +If you want to show differences between binary or specially-formatted +blobs in your repository, you can choose to use either an external diff +command, or to use textconv to convert them to a diff-able text format. +Which method you choose depends on your exact situation. + +The advantage of using an external diff command is flexibility. You are +not bound to find line-oriented changes, nor is it necessary for the +output to resemble unified diff. You are free to locate and report +changes in the most appropriate way for your data format. + +A textconv, by comparison, is much more limiting. You provide a +transformation of the data into a line-oriented text format, and git +uses its regular diff tools to generate the output. There are several +advantages to choosing this method: + +1. Ease of use. It is often much simpler to write a binary to text + transformation than it is to perform your own diff. In many cases, + existing programs can be used as textconv filters (e.g., exif, + odt2txt). + +2. Git diff features. By performing only the transformation step + yourself, you can still utilize many of git's diff features, + including colorization, word-diff, and combined diffs for merges. + +3. Caching. Textconv caching can speed up repeated diffs, such as those + you might trigger by running `git log -p`. + + +Marking files as binary +^^^^^^^^^^^^^^^^^^^^^^^ + +Git usually guesses correctly whether a blob contains text or binary +data by examining the beginning of the contents. However, sometimes you +may want to override its decision, either because a blob contains binary +data later in the file, or because the content, while technically +composed of text characters, is opaque to a human reader. For example, +many postscript files contain only ascii characters, but produce noisy +and meaningless diffs. + +The simplest way to mark a file as binary is to unset the diff +attribute in the `.gitattributes` file: + +------------------------ +*.ps -diff +------------------------ + +This will cause git to generate `Binary files differ` (or a binary +patch, if binary patches are enabled) instead of a regular diff. + +However, one may also want to specify other diff driver attributes. For +example, you might want to use `textconv` to convert postscript files to +an ascii representation for human viewing, but otherwise treat them as +binary files. You cannot specify both `-diff` and `diff=ps` attributes. +The solution is to use the `diff.*.binary` config option: + +------------------------ +[diff "ps"] + textconv = ps2ascii + binary = true +------------------------ + Performing a three-way merge ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `merge` ^^^^^^^ -The attribute `merge` affects how three versions of a file is +The attribute `merge` affects how three versions of a file are merged when a file-level merge is necessary during `git merge`, and other commands such as `git revert` and `git cherry-pick`. @@ -556,15 +677,15 @@ Unset:: Take the version from the current branch as the tentative merge result, and declare that the merge has - conflicts. This is suitable for binary files that does + conflicts. This is suitable for binary files that do not have a well-defined merge semantics. Unspecified:: By default, this uses the same built-in 3-way merge - driver as is the case the `merge` attribute is set. - However, `merge.default` configuration variable can name - different merge driver to be used for paths to which the + driver as is the case when the `merge` attribute is set. + However, the `merge.default` configuration variable can name + different merge driver to be used with paths for which the `merge` attribute is unspecified. String:: @@ -678,6 +799,8 @@ control per path. Set:: Notice all types of potential whitespace errors known to git. + The tab width is taken from the value of the `core.whitespace` + configuration variable. Unset:: @@ -685,13 +808,13 @@ Unset:: Unspecified:: - Use the value of `core.whitespace` configuration variable to + Use the value of the `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 + notice in the same format as the `core.whitespace` configuration variable. |