how to resolve brew update for Error " Failed to traverse parents of commit"

Error:

➜ local git:(master) brew update
Auto packing the repository in background for optimum performance.
See "git help gc" for manual housekeeping.
error: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

error: Could not read b1f1deb40aa1a9e22e1242ddc70f1e1c2d6ba9fa
fatal: Failed to traverse parents of commit 23ef4134e7ec6d829dd5a424e8820fb54aede480
error: failed to run repack

 

 

 

1.  go to brew git folder

#cd $(brew --prefix)

 

2.tree .git to see all git tree

 

3.

#git prune && git gc