GitLab

Stop processing the commit message text at a "diff --git" line.  Such
lines occur when the user commits with the "-v" option.  We should not
check the patch content; it will be stripped by Git anyway.

Commit "Reject leading TABs" added use of shell syntax of the form

  $(case "..." in
     a) ... ;;
    esac)

Some shell implementations fail to recognize that the ')' in the case
label is not the end of the '$(' expression.  Work around the problem
by moving the case block into a separate function outside the '$()'
expression.

Our style guidelines do not permit indentation by TABs.

Store a backup copy of the input message.  Remove the backup only on
success.  On failure, tell the user how to use and edit the message
without having to enter it from scratch.

These hooks perform some basic commit-time checks to keep history clean.