When you use git apply to apply a patch, and some hunks fail to apply, Git does not show which specific hunks failed by default. However, you can use the --reject option to save the rejected hunks to .rej files, which helps you identify which parts of the patch failed.

Steps to Identify Failed Hunks:

1. Use the --reject Option: Run the following command to apply the patch and save rejected hunks to .rej files:

   bash

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   git apply --reject <patch_file>

   • This will apply the parts of the patch that succeed and save the failed hunks to .rej files.

2. Check the .rej Files:

   • After running the command, look for .rej files in your working directory. These files will contain the hunks that failed to apply.
   • Each .rej file corresponds to a file in your repository and will show the context of the failed hunk.

3. Review the Output:

   • The terminal output will also indicate which files had conflicts or failed hunks.

Example Workflow:

git apply --reject my_patch.patch

• If there are conflicts, Git will create .rej files (e.g., file1.txt.rej, file2.txt.rej).
• Open these .rej files to see the exact hunks that failed to apply.

Additional Tips:

• Use git apply --check to test if a patch applies cleanly before actually applying it.
• If you want to see more detailed output, you can use the -v (verbose) flag:
  bash

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  git apply -v --reject my_patch.patch

This approach ensures you can identify and manually resolve the failed hunks.