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diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 1f472cea59..70899b3023 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -56,30 +56,45 @@ When more than one pattern matches the path, a later line overrides an earlier line. This overriding is done per attribute. The rules how the pattern matches paths are the same as in `.gitignore` files; see linkgit:gitignore[5]. +Unlike `.gitignore`, negative patterns are forbidden. -When deciding what attributes are assigned to a path, git +When deciding what attributes are assigned to a path, Git consults `$GIT_DIR/info/attributes` file (which has the highest precedence), `.gitattributes` file in the same directory as the path in question, and its parent directories up to the toplevel of the work tree (the further the directory that contains `.gitattributes` -is from the path in question, the lower its precedence). +is from the path in question, the lower its precedence). Finally +global and system-wide files are considered (they have the lowest +precedence). + +When the `.gitattributes` file is missing from the work tree, the +path in the index is used as a fall-back. During checkout process, +`.gitattributes` in the index is used and then the file in the +working tree is used as a fall-back. If you wish to affect only a single repository (i.e., to assign -attributes to files that are particular to one user's workflow), then +attributes to files that are particular to +one user's workflow for that repository), then attributes should be placed in the `$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]). +Its default value is $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME +is either not set or empty, $HOME/.config/git/attributes is used instead. +Attributes for all users on a system should be placed in the +`$(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 +for a path to `Unspecified` state. This can be done by listing the name of the attribute prefixed with an exclamation point `!`. EFFECTS ------- -Certain operations by git can be influenced by assigning +Certain operations by Git can be influenced by assigning particular attributes to a path. Currently, the following operations are attributes-aware. @@ -88,83 +103,184 @@ Checking-out and checking-in These attributes affect how the contents stored in the repository are copied to the working tree files when commands -such as 'git-checkout' and 'git-merge' run. They also affect how -git stores the contents you prepare in the working tree in the -repository upon 'git-add' and 'git-commit'. +such as 'git checkout' and 'git merge' run. They also affect how +Git stores the contents you prepare in the working tree in the +repository upon 'git add' and 'git commit'. -`crlf` +`text` ^^^^^^ -This attribute controls the line-ending convention. +This attribute enables and controls end-of-line normalization. When a +text file is normalized, its line endings are converted to LF in the +repository. To control what line ending style is used in the working +directory, use the `eol` attribute for a single file and the +`core.eol` configuration variable for all text files. Set:: - Setting the `crlf` attribute on a path is meant to mark - the path as a "text" file. 'core.autocrlf' conversion - takes place without guessing the content type by - inspection. + Setting the `text` attribute on a path enables end-of-line + normalization and marks the path as a text file. End-of-line + conversion takes place without guessing the content type. Unset:: - Unsetting the `crlf` attribute on a path tells git not to + Unsetting the `text` attribute on a path tells Git not to attempt any end-of-line conversion upon checkin or checkout. +Set to string value "auto":: + + When `text` is set to "auto", the path is marked for automatic + end-of-line normalization. If Git decides that the content is + text, its line endings are normalized to LF on checkin. + Unspecified:: - Unspecified `crlf` attribute tells git to apply the - `core.autocrlf` conversion when the file content looks - like text. + If the `text` attribute is unspecified, Git uses the + `core.autocrlf` configuration variable to determine if the + file should be converted. -Set to string value "input":: +Any other value causes Git to act as if `text` has been left +unspecified. - This is similar to setting the attribute to `true`, but - also forces git to act as if `core.autocrlf` is set to - `input` for the path. +`eol` +^^^^^ -Any other value set to `crlf` attribute is ignored and git acts -as if the attribute is left unspecified. +This attribute sets a specific line-ending style to be used in the +working directory. It enables end-of-line normalization without any +content checks, effectively setting the `text` attribute. +Set to string value "crlf":: -The `core.autocrlf` conversion -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + This setting forces Git to normalize line endings for this + file on checkin and convert them to CRLF when the file is + checked out. + +Set to string value "lf":: + + This setting forces Git to normalize line endings to LF on + checkin and prevents conversion to CRLF when the file is + checked out. + +Backwards compatibility with `crlf` attribute +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For backwards compatibility, the `crlf` attribute is interpreted as +follows: + +------------------------ +crlf text +-crlf -text +crlf=input eol=lf +------------------------ + +End-of-line conversion +^^^^^^^^^^^^^^^^^^^^^^ -If the configuration variable `core.autocrlf` is false, no -conversion is done. +While Git normally leaves file contents alone, it can be configured to +normalize line endings to LF in the repository and, optionally, to +convert them to CRLF when files are checked out. -When `core.autocrlf` is true, it means that the platform wants -CRLF line endings for files in the working tree, and you want to -convert them back to the normal LF line endings when checking -in to the repository. +Here is an example that will make Git normalize .txt, .vcproj and .sh +files, ensure that .vcproj files have CRLF and .sh files have LF in +the working directory, and prevent .jpg files from being normalized +regardless of their content. -When `core.autocrlf` is set to "input", line endings are -converted to LF upon checkin, but there is no conversion done -upon checkout. +------------------------ +*.txt text +*.vcproj eol=crlf +*.sh eol=lf +*.jpg -text +------------------------ + +Other source code management systems normalize all text files in their +repositories, and there are two ways to enable similar automatic +normalization in Git. + +If you simply want to have CRLF line endings in your working directory +regardless of the repository you are working with, you can set the +config variable "core.autocrlf" without changing any attributes. + +------------------------ +[core] + autocrlf = true +------------------------ + +This does not force normalization of all text files, but does ensure +that text files that you introduce to the repository have their line +endings normalized to LF when they are added, and that files that are +already normalized in the repository stay normalized. + +If you want to interoperate with a source code management system that +enforces end-of-line normalization, or you simply want all text files +in your repository to be normalized, you should instead set the `text` +attribute to "auto" for _all_ files. + +------------------------ +* text=auto +------------------------ -If `core.safecrlf` is set to "true" or "warn", git verifies if +This ensures that all files that Git considers to be text will have +normalized (LF) line endings in the repository. The `core.eol` +configuration variable controls which line endings Git will use for +normalized files in your working directory; the default is to use the +native line ending for your platform, or CRLF if `core.autocrlf` is +set. + +NOTE: When `text=auto` normalization is enabled in an existing +repository, any text files containing CRLFs should be normalized. If +they are not they will be normalized the next time someone tries to +change them, causing unfortunate misattribution. From a clean working +directory: + +------------------------------------------------- +$ echo "* text=auto" >>.gitattributes +$ rm .git/index # Remove the index to force Git to +$ git reset # re-scan the working directory +$ git status # Show files that will be normalized +$ git add -u +$ git add .gitattributes +$ git commit -m "Introduce end-of-line normalization" +------------------------------------------------- + +If any files that should not be normalized show up in 'git status', +unset their `text` attribute before running 'git add -u'. + +------------------------ +manual.pdf -text +------------------------ + +Conversely, text files that Git does not detect can have normalization +enabled manually. + +------------------------ +weirdchars.txt text +------------------------ + +If `core.safecrlf` is set to "true" or "warn", Git verifies if the conversion is reversible for the current setting of -`core.autocrlf`. For "true", git rejects irreversible -conversions; for "warn", git only prints a warning but accepts +`core.autocrlf`. For "true", Git rejects irreversible +conversions; for "warn", Git only prints a warning but accepts an irreversible conversion. The safety triggers to prevent such a conversion done to the files in the work tree, but there are a few exceptions. Even though... -- 'git-add' itself does not touch the files in the work tree, the +- 'git add' itself does not touch the files in the work tree, the next checkout would, so the safety triggers; -- 'git-apply' to update a text file with a patch does touch the files +- 'git apply' to update a text file with a patch does touch the files in the work tree, but the operation is about text files and CRLF conversion is about fixing the line ending inconsistencies, so the safety does not trigger; -- 'git-diff' itself does not touch the files in the work tree, it is - often run to inspect the changes you intend to next 'git-add'. To +- 'git diff' itself does not touch the files in the work tree, it is + often run to inspect the changes you intend to next 'git add'. To catch potential problems early, safety triggers. `ident` ^^^^^^^ -When the attribute `ident` is set for a path, git replaces +When the attribute `ident` is set for a path, Git replaces `$Id$` in the blob object with `$Id:`, followed by the 40-character hexadecimal blob object name, followed by a dollar sign `$` upon checkout. Any byte sequence that begins with @@ -186,16 +302,77 @@ output is used to update the worktree file. Similarly, the `clean` command is used to convert the contents of worktree file upon checkin. -A missing filter driver definition in the config is not an error -but makes the filter a no-op passthru. +One use of the content filtering is to massage the content into a shape +that is more convenient for the platform, filesystem, and the user to use. +For this mode of operation, 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. + +Another use of the content filtering is to store the content that cannot +be directly used in the repository (e.g. a UUID that refers to the true +content stored outside Git, or an encrypted content) and turn it into a +usable form upon checkout (e.g. download the external content, or decrypt +the encrypted content). + +These two filters behave differently, and by default, a filter is taken as +the former, massaging the contents into more convenient shape. A missing +filter driver definition in the config, or a filter driver that exits with +a non-zero status, is not an error but makes the filter a no-op passthru. + +You can declare that a filter turns a content that by itself is unusable +into a usable content by setting the filter.<driver>.required configuration +variable to `true`. + +For example, in .gitattributes, you would assign the `filter` +attribute for paths. -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 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. +------------------------ +*.c filter=indent +------------------------ + +Then you would define a "filter.indent.clean" and "filter.indent.smudge" +configuration in your .git/config to specify a pair of commands to +modify the contents of C programs when the source files are checked +in ("clean" is run) and checked out (no change is made because the +command is "cat"). + +------------------------ +[filter "indent"] + clean = indent + 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. + +If a filter _must_ succeed in order to make the stored contents usable, +you can declare that the filter is `required`, in the configuration: + +------------------------ +[filter "crypt"] + clean = openssl enc ... + smudge = openssl enc -d ... + required +------------------------ + +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 @@ -204,11 +381,34 @@ Interaction between checkin/checkout attributes In the check-in codepath, the worktree file is first converted with `filter` driver (if specified and corresponding driver defined), then the result is processed with `ident` (if -specified), and then finally with `crlf` (again, if specified +specified), and then finally with `text` (again, if specified and applicable). In the check-out codepath, the blob content is first converted -with `crlf`, and then `ident` and fed to `filter`. +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 @@ -217,11 +417,11 @@ Generating diff text `diff` ^^^^^^ -The attribute `diff` affects how 'git' generates diffs for particular -files. It can tell git whether to generate a textual patch for the path +The attribute `diff` affects how Git generates diffs for particular +files. It can tell Git whether to generate a textual patch for the path or to treat the path as a binary file. It can also affect what line is -shown on the hunk header `@@ -k,l +n,m @@` line, tell git to use an -external command to generate the diff, or ask git to convert binary +shown on the hunk header `@@ -k,l +n,m @@` line, tell Git to use an +external command to generate the diff, or ask Git to convert binary files to a text format before generating the diff. Set:: @@ -240,8 +440,8 @@ Unspecified:: A path to which the `diff` attribute is unspecified first gets its contents inspected, and if it looks like - text, it is treated as text. Otherwise it would - generate `Binary files differ`. + text and is smaller than core.bigFileThreshold, it is treated + as text. Otherwise it would generate `Binary files differ`. String:: @@ -249,7 +449,7 @@ String:: specify one or more options, as described in the following section. The options for the diff driver "foo" are defined by the configuration variables in the "diff.foo" section of the - git config file. + Git config file. Defining an external diff driver @@ -267,7 +467,7 @@ To define an external diff driver `jcdiff`, add a section to your command = j-c-diff ---------------------------------------------------------------- -When git needs to show you a diff for the path with `diff` +When Git needs to show you a diff for the path with `diff` 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. @@ -317,18 +517,28 @@ configuration file (you still need to enable this with the attribute mechanism, via `.gitattributes`). The following built in patterns are available: +- `ada` suitable for source code in the Ada language. + - `bibtex` suitable for files with BibTeX coded references. - `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. +- `matlab` suitable for source code in the MATLAB language. + - `objc` suitable for source code in the Objective-C language. - `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. @@ -341,7 +551,7 @@ patterns are available: Customizing word diff ^^^^^^^^^^^^^^^^^^^^^ -You can customize the rules that `git diff --color-words` uses to +You can customize the rules that `git diff --word-diff` uses to split words in a line, by specifying an appropriate regular expression in the "diff.*.wordRegex" configuration variable. For example, in TeX a backslash followed by a sequence of letters forms a command, but @@ -395,6 +605,90 @@ because it quickly conveys the changes you have made), you should generate it separately and send it as a comment _in addition to_ the usual binary diff that you might send. +Because text conversion can be slow, especially when doing a +large number of them with `git log -p`, Git provides a mechanism +to cache the output and use it in future diffs. To enable +caching, set the "cachetextconv" variable in your diff driver's +config. For example: + +------------------------ +[diff "jpg"] + textconv = exif + cachetextconv = true +------------------------ + +This will cache the result of running "exif" on each blob +indefinitely. If you change the textconv config variable for a +diff driver, Git will automatically invalidate the cache entries +and re-run the textconv filter. If you want to invalidate the +cache manually (e.g., because your version of "exif" was updated +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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -402,7 +696,7 @@ 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`. @@ -416,15 +710,15 @@ 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:: @@ -492,7 +786,8 @@ command to run to merge ancestor's version (`%O`), current version (`%A`) and the other branches' version (`%B`). These three tokens are replaced with the names of temporary files that hold the contents of these versions when the command line is -built. +built. Additionally, %L will be replaced with the conflict marker +size (see below). The merge driver is expected to leave the result of the merge in the file named with `%A` by overwriting it, and exit with zero @@ -506,6 +801,23 @@ When left unspecified, the driver itself is used for both internal merge and the final merge. +`conflict-marker-size` +^^^^^^^^^^^^^^^^^^^^^^ + +This attribute controls the length of conflict markers left in +the work tree file during a conflicted merge. Only setting to +the value to a positive integer has any meaningful effect. + +For example, this line in `.gitattributes` can be used to tell the merge +machinery to leave much longer (instead of the usual 7-character-long) +conflict markers when merging the file `Documentation/git-merge.txt` +results in a conflict. + +------------------------ +Documentation/git-merge.txt conflict-marker-size=32 +------------------------ + + Checking whitespace errors ~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -519,7 +831,9 @@ control per path. Set:: - Notice all types of potential whitespace errors known to git. + 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:: @@ -527,13 +841,13 @@ 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. @@ -549,7 +863,7 @@ archive files. `export-subst` ^^^^^^^^^^^^^^ -If the attribute `export-subst` is set for a file then git will expand +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 @@ -587,38 +901,44 @@ If this attribute is not set or has an invalid value, the value of the (See linkgit:git-config[1]). -USING ATTRIBUTE MACROS +USING MACRO ATTRIBUTES ---------------------- You do not want any end-of-line conversions applied to, nor textual diffs produced for, any binary file you track. You would need to specify e.g. ------------ -*.jpg -crlf -diff +*.jpg -text -diff ------------ but that may become cumbersome, when you have many attributes. Using -attribute macros, you can specify groups of attributes set or unset at -the same time. The system knows a built-in attribute macro, `binary`: +macro attributes, you can define an attribute that, when set, also +sets or unsets a number of other attributes at the same time. The +system knows a built-in macro attribute, `binary`: ------------ *.jpg binary ------------ -which is equivalent to the above. Note that the attribute macros can only -be "Set" (see the above example that sets "binary" macro as if it were an -ordinary attribute --- setting it in turn unsets "crlf" and "diff"). +Setting the "binary" attribute also unsets the "text" and "diff" +attributes as above. Note that macro attributes can only be "Set", +though setting one might have the effect of setting or unsetting other +attributes or even returning other attributes to the "Unspecified" +state. -DEFINING ATTRIBUTE MACROS +DEFINING MACRO ATTRIBUTES ------------------------- -Custom attribute macros can be defined only in the `.gitattributes` file -at the toplevel (i.e. not in any subdirectory). The built-in attribute -macro "binary" is equivalent to: +Custom macro attributes can be defined only in top-level gitattributes +files (`$GIT_DIR/info/attributes`, the `.gitattributes` file at the +top level of the working tree, or the global or system-wide +gitattributes files), not in `.gitattributes` files in working tree +subdirectories. The built-in macro attribute "binary" is equivalent +to: ------------ -[attr]binary -diff -crlf +[attr]binary -diff -merge -text ------------ @@ -644,7 +964,7 @@ abc -foo -bar the attributes given to path `t/abc` are computed as follows: 1. By examining `t/.gitattributes` (which is in the same - directory 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. @@ -671,6 +991,9 @@ frotz unspecified ---------------------------------------------------------------- +SEE ALSO +-------- +linkgit:git-check-attr[1]. GIT --- |