Steps to git-bisect

dask-git-bisect.md

Git bisect to identify bad commit (here dask is used as an example)

Prerequisites to git bisect:

• Know how to build dask from source
• Known good commit eg: Dask version 2.4
• Known bad commit eg: Dask version 2.5
• Have a script/test that fails with bad commit but works with good commit
• Ensure that the test indeed fails with dask built from source with bad commit and passes for dask built from source with good commit. (In the existing environment)

Git-bisect:

1. $ git bisect start
2. $ git bisect good <good-commit-hash>
3. $ git bisect bad <bad-commit-hash>
4. Git automatically chooses a commit between the good and bad state.
5. Build dask
6. Run the test
7. Two possibilities:

• If the test fails: $ git bisect bad
• If the test passes: $ git bisect good

8. Keep repeating steps 5-7 till you narrow down the specific commit that broke things
9. $ git bisect reset to stop git bisect.