Case insensitive branch names

On the Git User's list, Diego J. reported that:

'When I "checkout" a branch using different Upper Case/Lower Case than the original, the branch doesn't show in "git branch [--list]"' [1]

While case sensitivity for filenames is a common issue on Windows and the like, I haven't seen any discussion regarding ref name sensitivity - any pointers to past discussions?

In particular, if I have a branch 'nocase', and ask to checkout 'NoCase', then git(-for-Windows) will happily say that 'NoCase' has been checked out, but then it gets confusing.

We are both, not on any branch, and yet not detached. In fact HEAD points to NoCase (which does not exist with that case setting). The checkout is actually of 'nocase', and 'git branch' does not mark any branch ref current (with the *). [see test script: 2].

While this is the way it is, should the 'git checkout' in some way check for the branch case sensitivity issue?

For example, maybe simply correcting the checkout name to that as recorded in the File System (but that has lots of code impact because the path and name are distinct elements of the branch struct), or maybe a warning could be emitted (config?), or even an err/die.

My gut feeling was that, at least for refs, that something should be done. My delving into the complexities of the code for 'git checkout' got me to refs.c ~#L1603 where the requested path is lstat'd. Perhaps this point is a special case for the mingw_lstat where the true pathname can be compared to the requested pathname (or at least the refs/heads/name part) to detect this mis-checkout case?

Thoughts? Is it a rabbit hole others have explored? Is it even worth pursuing?

-- Philip

[1] https://groups.google.com/forum/#!topic/git-users/EryCnwKL4_E [2] Script git init casetest cd casetest/

git add -A & git commit -m'first' git status git branch case git branch # two branches, * on master. git status git checkout Case # successful checkout, uses branch name as given! git branch # note that no branch is marked as current, but neither are we detached head.. git status cat .git/HEAD # HEAD records the requested name, not the branch that was actually checked out! # User left confused...

=== output Philip@PhilipOakley MINGW32 /c $ bash -v ./casetest.sh

git init casetest Initialized empty Git repository in C:/casetest/.git/ cd casetest/

git add -A & git commit -m'first'
[master (root-commit) 988c046] first
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 temp.txt
git status
On branch master
nothing to commit, working directory clean
git branch case
git branch
case
* master
# two branches, * on master.
git status
On branch master
nothing to commit, working directory clean
git checkout Case
Switched to branch 'Case'
# successful checkout, uses branch name as given!
git branch
case
master
# note that no branch is marked as current, but neither are we detached 
head..
git status
On branch Case
nothing to commit, working directory clean
cat .git/HEAD
ref: refs/heads/Case
# HEAD records the requested name, not the branch that was actually checked 
out!
# User left confused..