Git Line Ending

due to history reason, for different operation system, it has different line-ending,

  • for Windows, it is \r\n, CRLF named carriage return line feeding
  • for Unix, it is \n, LF named line feeding
  • for Mac, it is \r, CR named carriage return

in order to make end-of-line compatible and keep consistent, it comes to git-autocrlf setting.

generally speaking, it has two types of repos to handle, the commit and current (can be checked-out) repositories.

core.autocrlf

table to show difference:

| core.autocrlf |     false    |     input    |     true     |
|---------------|--------------|--------------|--------------|
|               | LF => LF     | LF => LF     | LF => LF     |
|  git commit   | CR => CR     | CR => CR     | CR => CR     |
|               | CRLF => CRLF | CRLF => LF   | CRLF => LF   |
|---------------|--------------|--------------|--------------|
|               | LF => LF     | LF => LF     | LF => CRLF   |
| git checkout  | CR => CR     | CR => CR     | CR => CR     |
|               | CRLF => CRLF | CRLF => CRLF | CRLF => CRLF |
|---------------|--------------|--------------|--------------|

explanations

  • when core.autocrlf is set to input and git commit is executed, if current line-ending is CRLF, then it will be transferred to LF.

  • when core.autocrlf is set to true and git checkout is executed, if you are using windows system, then the commit line-ending LF will be transferred to CRLF.

No matter what your setting is, your current-and-early working tree will not be influenced.

core.safecrlf

core.safecrlf only works when core.autocrlf is set to input or true

      core.autocrlf     |     input      |     true    
------------------------|----------------|-------------
      git commit        |   CRLF => LF   |   CRLF => LF
------------------------|----------------|-------------
               |  warn  |     Warning    |    Warning  
core.safecrlf  |--------|----------------|-------------
               |  true  |     Fatal      |    Fatal

explanations

  • when core.safecrlf is set to warn and git commit is executed, if current line-ending is CRLF, then it will be transferred to LF, at the same time, the warning message will be prompted like:
warning: CRLF will be replaced by LF in <FILEPATH>.
  • when core.safecrlf is set to true, any line-ending difference caused by git commit & git checkout will be rejected, the prompt message will be like:
fatal: CRLF would be replaced by LF in <FILEPATH>.

Why? Because it will cause inconsistence between files.

For example, if you are using windows system, and the line-ending for your working file is CRLF, if you set core.autocrlf = true, following this setting, git will make conversions between your working-tree and commit.

If it succeeded, then CRLF would be transferred to LF, however, this behavior is not allowed when core.safecrlf is set to true, it is like that you are explicitly telling git that you do not want to make this type of changes, and as a result, git, like it always does, will strictly execute your commands.