Syntax Highlighting

GitLab provides syntax highlighting on all files through the Rouge Ruby gem. It attempts to guess what language to use based on the file extension, which most of the time is sufficient.

note The Web IDE and Snippets use Monaco Editor for text editing, which internally uses the Monarch library for syntax highlighting.

If GitLab is guessing wrong, you can override its choice of language using the gitlab-language attribute in .gitattributes. For example, if you are working in a Prolog project and using the .pl file extension (which would normally be highlighted as Perl), you can add the following to your .gitattributes file:

*.pl gitlab-language=prolog

When you check in and push that change, all *.pl files in your project are highlighted as Prolog.

The paths here are Git’s built-in .gitattributes interface. So, if you were to invent a file format called a Nicefile at the root of your project that used Ruby syntax, all you need is:

/Nicefile gitlab-language=ruby

To disable highlighting entirely, use gitlab-language=text. Lots more fun shenanigans are available through common gateway interface (CGI) options, such as:

# json with erb in it
/my-cool-file gitlab-language=erb?parent=json

# an entire file of highlighting errors!
/other-file gitlab-language=text?token=Error

Please note that these configurations only take effect when the .gitattributes file is in your default branch (usually master).

note The Web IDE does not support .gitattribute files, but it’s planned for a future release.