fatal: git-write-tree: error building trees

Question

I did a git pull from a shared git repository, but something went really wrong, after I tried a git revert. Here is the situation now:

$ git stash
Source/MediaStorageAndFileFormat/gdcmImageCodec.cxx: needs merge
Source/MediaStorageAndFileFormat/gdcmJPEGLSCodec.cxx: needs merge
Source/MediaStorageAndFileFormat/gdcmPNMCodec.cxx: needs merge
Testing/Source/DataStructureAndEncodingDefinition/Cxx/TestDS.cxx: needs merge
Utilities/socketxx/socket++/sockstream.cpp: needs merge
Source/MediaStorageAndFileFormat/gdcmImageCodec.cxx: needs merge
Source/MediaStorageAndFileFormat/gdcmJPEGLSCodec.cxx: needs merge
Source/MediaStorageAndFileFormat/gdcmPNMCodec.cxx: needs merge
Testing/Source/DataStructureAndEncodingDefinition/Cxx/TestDS.cxx: needs merge
Utilities/socketxx/socket++/sockstream.cpp: needs merge
Source/MediaStorageAndFileFormat/gdcmImageCodec.cxx: unmerged (2aafac967c35fa4e77c3086b83a3c102939ad168)
Source/MediaStorageAndFileFormat/gdcmImageCodec.cxx: unmerged (78cc95e8bae85bf8345a7793676e878e83df167b)
Source/MediaStorageAndFileFormat/gdcmImageCodec.cxx: unmerged (2524db713fbde0d7ebd86bfe2afc4b4d7d48db33)
Source/MediaStorageAndFileFormat/gdcmJPEGLSCodec.cxx: unmerged (4bb4ba78973091eaa854b03c6ce24e8f4af9e7cc)
Source/MediaStorageAndFileFormat/gdcmJPEGLSCodec.cxx: unmerged (ad0982b8b8b4c4fef23e69bbb639ca6d0cd98dd8)
Source/MediaStorageAndFileFormat/gdcmJPEGLSCodec.cxx: unmerged (4868371b7218c6e007fb6c582ad4ab226167a80a)
Source/MediaStorageAndFileFormat/gdcmPNMCodec.cxx: unmerged (f7a1b386b5b13b8fa8b6a31ce1258d2d5e5b13c5)
Source/MediaStorageAndFileFormat/gdcmPNMCodec.cxx: unmerged (6ce299c416fbb3bb60e11ef1e54962ffd3449a4c)
Source/MediaStorageAndFileFormat/gdcmPNMCodec.cxx: unmerged (75c8043a60a56a1130a34cdbd91d130bc9343c1c)
Testing/Source/DataStructureAndEncodingDefinition/Cxx/TestDS.cxx: unmerged (79c2843f2649ea9c87fa57662dafd899a5fa39ee)
...
fatal: git-write-tree: error building trees
Cannot save the current index state

Is there a way to reset all that ?

Thanks

Quack

Answer 1

Use

git reset --mixed

instead of git reset --hard. You will not lose any changes.

Allurement

Note that the --mixed argument is also git reset's default behavior, when not given an argument. manpage for reference. – Tuberculin

Valid answer, but would be nice to have an explanation for what happened and why this was necessary. – Disorderly

@Disorderly Yeah - I'd like to see an explanation of why git reset with the (default) --mixed option is appropriate and effective here also. According to merge - Git unmerged path issue: This will switch to HEAD, and tell git to forget any merge conflicts, and leave the working directory as is. heracek, is that what's going on? – Santoro

Doesn't work. I get git: 'reset--mixed' is not a git command. See 'git --help'. – Bois

@Bois Months late, but note the space between reset and the hyphens. – Venter

FWIW I ran into this issue when I was doing git stash. Doing git reset --mixed resolved it. – Philana

Answer 2

This worked for me:

Do

$ git status

And check if you have Unmerged paths

# Unmerged paths:
#   (use "git reset HEAD <file>..." to unstage)
#   (use "git add <file>..." to mark resolution)
#
#   both modified:      app/assets/images/logo.png
#   both modified:      app/models/laundry.rb

Fix them with git add to each of them and try git stash again.

git add app/assets/images/logo.png

Proscenium

This worked for me. git reset --mixed may be better than world peace, but without some explanation of what it does, I ain't touching it. In my case, there was a collision in an earlier pull that I didn't notice. The stash failed because of the unresolved pull. – Conclusion

I don't understand this strategy any better than git reset --mixed, but it worked, and seemed like a better fit for my case because I got the error after git stash rather than git revert. – Induration

An unmerged path means you have run git merge, or the equivalent of git merge, and it tried to merge two different sets of changes to that file, but failed. – Tiernan

This worked for me, too, after attempting to do a git stash. I had to do a git add <file> first, then the stash succeeded. – Herbert

Answer 3

To follow up on malat's response, you can avoid losing changes by creating a patch and reapply it at a later time.

git diff --no-prefix > patch.txt
patch -p0 < patch.txt

Store your patch outside the repository folder for safety.

Animation

This gave me: SDGL132d9f4b4:glitch-common dstromberg$ patch -p0 < /tmp/patch.txt patch: **** Only garbage was found in the patch input. – Batik

I think you should mv the patch back again into the directory where you created it from. 1. git diff 2. mv patch.txt /tmp3. git stash 4. mv /tmp/patch.txt . 5. patch -p0 – Rickets

Answer 4

I used:

 git reset --hard

I lost some changes, but this is ok.

Quack

Just a note: git revert attempts to merge changes from the past; you have correctly used git reset to simply rewind the clock. It is unfortunate that git stash does not work with merge conflicts. – Exotoxin

If you lose changes, this is not a fix ;) – Flit

Answer 5

maybe there are some unmerged paths in your git repository that you have to resolve before stashing.

Kort

This helped me so I will give it a +1. But I put a more extended answer. – Proscenium

Answer 6

This happened to me when trying to merge another branch. The merge failed with fatal: git-write-tree: error building trees and complained about a different file that had nothing to do with the merge. My branch then contained the files it had tried to merge, as uncommitted changes.

I cleared the changes it had attempted to merge, then removed the problem file and rebuilt the hash:

git reset --hard;

git rm --cache problem_file.txt;

git hash-object -w problem_file.txt;

The merge then worked.

Impressment

Answer 7

This happened for me when I was trying to stash my changes, but then my changes had conflicts with my branch's current state.

So I did git reset --mixed and then resolved the git conflict and stashed again.

Philana