diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/config.txt | 45 | ||||
| -rw-r--r-- | Documentation/gitattributes.txt | 20 |
2 files changed, 65 insertions, 0 deletions
diff --git a/Documentation/config.txt b/Documentation/config.txt index f9bdb16..f2f6a77 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -139,6 +139,51 @@ core.autocrlf:: "text" (i.e. be subjected to the autocrlf mechanism) is decided purely based on the contents. +core.safecrlf:: + If true, makes git check if converting `CRLF` as controlled by + `core.autocrlf` is reversible. Git will verify if a command + modifies a file in the work tree either directly or indirectly. + For example, committing a file followed by checking out the + same file should yield the original file in the work tree. If + this is not the case for the current setting of + `core.autocrlf`, git will reject the file. The variable can + be set to "warn", in which case git will only warn about an + irreversible conversion but continue the operation. ++ +CRLF conversion bears a slight chance of corrupting data. +autocrlf=true will convert CRLF to LF during commit and LF to +CRLF during checkout. A file that contains a mixture of LF and +CRLF before the commit cannot be recreated by git. For text +files this is the right thing to do: it corrects line endings +such that we have only LF line endings in the repository. +But for binary files that are accidentally classified as text the +conversion can corrupt data. ++ +If you recognize such corruption early you can easily fix it by +setting the conversion type explicitly in .gitattributes. Right +after committing you still have the original file in your work +tree and this file is not yet corrupted. You can explicitly tell +git that this file is binary and git will handle the file +appropriately. ++ +Unfortunately, the desired effect of cleaning up text files with +mixed line endings and the undesired effect of corrupting binary +files cannot be distinguished. In both cases CRLFs are removed +in an irreversible way. For text files this is the right thing +to do because CRLFs are line endings, while for binary files +converting CRLFs corrupts data. ++ +Note, this safety check does not mean that a checkout will generate a +file identical to the original file for a different setting of +`core.autocrlf`, but only for the current one. For example, a text +file with `LF` would be accepted with `core.autocrlf=input` and could +later be checked out with `core.autocrlf=true`, in which case the +resulting file would contain `CRLF`, although the original file +contained `LF`. However, in both work trees the line endings would be +consistent, that is either all `LF` or all `CRLF`, but never mixed. A +file with mixed line endings would be reported by the `core.safecrlf` +mechanism. + core.symlinks:: If false, symbolic links are checked out as small plain files that contain the link text. linkgit:git-update-index[1] and diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 35a29fd..84ec962 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -133,6 +133,26 @@ When `core.autocrlf` is set to "input", line endings are converted to LF upon checkin, but there is no conversion done upon checkout. +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 +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 + next checkout would, so the safety triggers; + +- "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 + catch potential problems early, safety triggers. + `ident` ^^^^^^^ |