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Diffstat (limited to 'Documentation/gitattributes.txt')
| -rw-r--r-- | Documentation/gitattributes.txt | 235 |
1 files changed, 179 insertions, 56 deletions
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index a53d093ca1..b8392fc330 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -3,7 +3,7 @@ gitattributes(5) NAME ---- -gitattributes - defining attributes per path +gitattributes - Defining attributes per path SYNOPSIS -------- @@ -56,9 +56,16 @@ Unspecified:: 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. +attribute. + +The rules by which the pattern matches paths are the same as in +`.gitignore` files (see linkgit:gitignore[5]), with a few exceptions: + + - negative patterns are forbidden + + - patterns that match a directory do not recursively match paths + inside that directory (so using the trailing-slash `path/` syntax is + pointless in an attributes file; use `path/**` instead) When deciding what attributes are assigned to a path, Git consults `$GIT_DIR/info/attributes` file (which has the highest @@ -151,7 +158,10 @@ unspecified. This attribute sets a specific line-ending style to be used in the working directory. It enables end-of-line conversion without any -content checks, effectively setting the `text` attribute. +content checks, effectively setting the `text` attribute. Note that +setting this attribute on paths which are in the index with CRLF line +endings may make the paths to be considered dirty. Adding the path to +the index again will normalize the line endings in the index. Set to string value "crlf":: @@ -229,11 +239,8 @@ 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 add --renormalize . $ git status # Show files that will be normalized -$ git add -u -$ git add .gitattributes $ git commit -m "Introduce end-of-line normalization" ------------------------------------------------- @@ -272,6 +279,94 @@ few exceptions. Even though... catch potential problems early, safety triggers. +`working-tree-encoding` +^^^^^^^^^^^^^^^^^^^^^^^ + +Git recognizes files encoded in ASCII or one of its supersets (e.g. +UTF-8, ISO-8859-1, ...) as text files. Files encoded in certain other +encodings (e.g. UTF-16) are interpreted as binary and consequently +built-in Git text processing tools (e.g. 'git diff') as well as most Git +web front ends do not visualize the contents of these files by default. + +In these cases you can tell Git the encoding of a file in the working +directory with the `working-tree-encoding` attribute. If a file with this +attribute is added to Git, then Git reencodes the content from the +specified encoding to UTF-8. Finally, Git stores the UTF-8 encoded +content in its internal data structure (called "the index"). On checkout +the content is reencoded back to the specified encoding. + +Please note that using the `working-tree-encoding` attribute may have a +number of pitfalls: + +- Alternative Git implementations (e.g. JGit or libgit2) and older Git + versions (as of March 2018) do not support the `working-tree-encoding` + attribute. If you decide to use the `working-tree-encoding` attribute + in your repository, then it is strongly recommended to ensure that all + clients working with the repository support it. ++ +For example, Microsoft Visual Studio resources files (`*.rc`) or +PowerShell script files (`*.ps1`) are sometimes encoded in UTF-16. +If you declare `*.ps1` as files as UTF-16 and you add `foo.ps1` with +a `working-tree-encoding` enabled Git client, then `foo.ps1` will be +stored as UTF-8 internally. A client without `working-tree-encoding` +support will checkout `foo.ps1` as UTF-8 encoded file. This will +typically cause trouble for the users of this file. ++ +If a Git client, that does not support the `working-tree-encoding` +attribute, adds a new file `bar.ps1`, then `bar.ps1` will be +stored "as-is" internally (in this example probably as UTF-16). +A client with `working-tree-encoding` support will interpret the +internal contents as UTF-8 and try to convert it to UTF-16 on checkout. +That operation will fail and cause an error. + +- Reencoding content to non-UTF encodings can cause errors as the + conversion might not be UTF-8 round trip safe. If you suspect your + encoding to not be round trip safe, then add it to + `core.checkRoundtripEncoding` to make Git check the round trip + encoding (see linkgit:git-config[1]). SHIFT-JIS (Japanese character + set) is known to have round trip issues with UTF-8 and is checked by + default. + +- Reencoding content requires resources that might slow down certain + Git operations (e.g 'git checkout' or 'git add'). + +Use the `working-tree-encoding` attribute only if you cannot store a file +in UTF-8 encoding and if you want Git to be able to process the content +as text. + +As an example, use the following attributes if your '*.ps1' files are +UTF-16 encoded with byte order mark (BOM) and you want Git to perform +automatic line ending conversion based on your platform. + +------------------------ +*.ps1 text working-tree-encoding=UTF-16 +------------------------ + +Use the following attributes if your '*.ps1' files are UTF-16 little +endian encoded without BOM and you want Git to use Windows line endings +in the working directory. Please note, it is highly recommended to +explicitly define the line endings with `eol` if the `working-tree-encoding` +attribute is used to avoid ambiguity. + +------------------------ +*.ps1 text working-tree-encoding=UTF-16LE eol=CRLF +------------------------ + +You can get a list of all available encodings on your platform with the +following command: + +------------------------ +iconv --list +------------------------ + +If you do not know the encoding of a file, then you can use the `file` +command to guess the encoding: + +------------------------ +file foo.ps1 +------------------------ + + `ident` ^^^^^^^ @@ -327,6 +422,9 @@ 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`. +Note: Whenever the clean filter is changed, the repo should be renormalized: +$ git add --renormalize . + For example, in .gitattributes, you would assign the `filter` attribute for paths. @@ -389,46 +487,14 @@ Long Running Filter Process If the filter command (a string value) is defined via `filter.<driver>.process` then Git can process all blobs with a single filter invocation for the entire life of a single Git -command. This is achieved by using a packet format (pkt-line, -see technical/protocol-common.txt) based protocol over standard -input and standard output as follows. All packets, except for the -"*CONTENT" packets and the "0000" flush packet, are considered -text and therefore are terminated by a LF. - -Git starts the filter when it encounters the first file -that needs to be cleaned or smudged. After the filter started -Git sends a welcome message ("git-filter-client"), a list of supported -protocol version numbers, and a flush packet. Git expects to read a welcome -response message ("git-filter-server"), exactly one protocol version number -from the previously sent list, and a flush packet. All further -communication will be based on the selected version. The remaining -protocol description below documents "version=2". Please note that -"version=42" in the example below does not exist and is only there -to illustrate how the protocol would look like with more than one -version. - -After the version negotiation Git sends a list of all capabilities that -it supports and a flush packet. Git expects to read a list of desired -capabilities, which must be a subset of the supported capabilities list, -and a flush packet as response: ------------------------- -packet: git> git-filter-client -packet: git> version=2 -packet: git> version=42 -packet: git> 0000 -packet: git< git-filter-server -packet: git< version=2 -packet: git< 0000 -packet: git> capability=clean -packet: git> capability=smudge -packet: git> capability=not-yet-invented -packet: git> 0000 -packet: git< capability=clean -packet: git< capability=smudge -packet: git< 0000 ------------------------- -Supported filter capabilities in version 2 are "clean" and -"smudge". +command. This is achieved by using the long-running process protocol +(described in technical/long-running-process-protocol.txt). + +When Git encounters the first file that needs to be cleaned or smudged, +it starts the filter and performs the handshake. In the handshake, the +welcome message sent by Git is "git-filter-client", only version 2 is +suppported, and the supported capabilities are "clean", "smudge", and +"delay". Afterwards Git sends a list of "key=value" pairs terminated with a flush packet. The list will contain at least the filter command @@ -514,11 +580,66 @@ the protocol then Git will stop the filter process and restart it with the next file that needs to be processed. Depending on the `filter.<driver>.required` flag Git will interpret that as error. -After the filter has processed a blob it is expected to wait for -the next "key=value" list containing a command. Git will close -the command pipe on exit. The filter is expected to detect EOF -and exit gracefully on its own. Git will wait until the filter -process has stopped. +Delay +^^^^^ + +If the filter supports the "delay" capability, then Git can send the +flag "can-delay" after the filter command and pathname. This flag +denotes that the filter can delay filtering the current blob (e.g. to +compensate network latencies) by responding with no content but with +the status "delayed" and a flush packet. +------------------------ +packet: git> command=smudge +packet: git> pathname=path/testfile.dat +packet: git> can-delay=1 +packet: git> 0000 +packet: git> CONTENT +packet: git> 0000 +packet: git< status=delayed +packet: git< 0000 +------------------------ + +If the filter supports the "delay" capability then it must support the +"list_available_blobs" command. If Git sends this command, then the +filter is expected to return a list of pathnames representing blobs +that have been delayed earlier and are now available. +The list must be terminated with a flush packet followed +by a "success" status that is also terminated with a flush packet. If +no blobs for the delayed paths are available, yet, then the filter is +expected to block the response until at least one blob becomes +available. The filter can tell Git that it has no more delayed blobs +by sending an empty list. As soon as the filter responds with an empty +list, Git stops asking. All blobs that Git has not received at this +point are considered missing and will result in an error. + +------------------------ +packet: git> command=list_available_blobs +packet: git> 0000 +packet: git< pathname=path/testfile.dat +packet: git< pathname=path/otherfile.dat +packet: git< 0000 +packet: git< status=success +packet: git< 0000 +------------------------ + +After Git received the pathnames, it will request the corresponding +blobs again. These requests contain a pathname and an empty content +section. The filter is expected to respond with the smudged content +in the usual way as explained above. +------------------------ +packet: git> command=smudge +packet: git> pathname=path/testfile.dat +packet: git> 0000 +packet: git> 0000 # empty content! +packet: git< status=success +packet: git< 0000 +packet: git< SMUDGED_CONTENT +packet: git< 0000 +packet: git< 0000 # empty list, keep "status=success" unchanged! +------------------------ + +Example +^^^^^^^ A long running filter demo implementation can be found in `contrib/long-running-filter/example.pl` located in the Git @@ -688,6 +809,8 @@ patterns are available: - `fountain` suitable for Fountain documents. +- `golang` suitable for source code in the Go language. + - `html` suitable for HTML/XHTML documents. - `java` suitable for source code in the Java language. @@ -1106,8 +1229,8 @@ to: ------------ -EXAMPLE -------- +EXAMPLES +-------- If you have these three `gitattributes` file: |