git diff-tree shows no output

Question

I have read that the following command allows you to see all changed files of the last commit:

git diff-tree --no-commit-id --diff-filter=d --name-only -r $(Build.SourceVersion)

Unfortunately I have no luck, the command does not show anything. How is that possible? I am currently on a branch called swagger-fix, so maybe the command is not able to see the branch? Thank you for your help.

Answer 1

torek's comment is spot on:

Carnac the Magnificent says: You're using a CI system and you've forgotten to turn off shallow clones in the CI system. Turn off shallow clones (or set the depth to be at least 2).

So make sure to include such crucial information in your future questions :)

The solution: unshallow your CI clone or turn of shallow clones altogether.

Answer 2

I also had similar problem, I was trying to run this command in docker-image.yml file and I found that when It clone repo for CI, it do a shellow copy.

to fix this is docker-image.yml you need to add following.

jobs:
  build-and-deploy:
    runs-on: [self-hosted]
    steps:
      
      - name: Checkout code
        uses: actions/checkout@v2
        with:
          fetch-depth: 0

This fetch-depth: 0, will ensure to fetch all commit history, so then you will be able to get changed file from commit.

Additionally, this might help you, who I'm getting changed files

- name: Get changed files
        id: changed-files
        run: |
          touch ${{ github.workspace }}/changed_files.txt
          echo ${{github.sha}}
          echo $(git diff-tree --no-commit-id --name-only ${{github.sha}} -r) > changed_files.txt
          cat ${{ github.workspace }}/changed_files.txt ; echo

Answer 3

Git's diffing will bypass merge commits unless you explicitly either ask for both/all parents with -m or --cc or specify which parent you're diffing against. Try specifying the first parent, $(Build.SourceVersion)~ $(Build.SourceVersion) This will have the added benefit of popping a complaint if you're inadvertently working with a shallow clone.