git diff-tree ignores --textconv

Hi,

I'm using a 3rd party application that internally uses 'git diff-tree' instead of 'git diff'. I'm trying to add filter and it works with 'git diff' but it gets ignored with 'git diff-tree' despite having --textconv.

I was able to reproduce the problem with the following much more simplified setup:

$ git check-attr diff test/test.ipynb test/test.ipynb: diff: jupyternotebook

$ git config --get diff.jupyternotebook.command git-nbdiffdriver diff

$ GIT_TRACE=1 git diff test/test.ipynb [...] run_command: GIT_DIFF_PATH_COUNTER=1 GIT_DIFF_PATH_TOTAL=1 'git-nbdiffdriver diff' [...] <shows nbdiff output as desired>

$ GIT_TRACE=1 git diff-tree -p HEAD --textconv test/test.ipynb <shows normal diff, ignoring nbdiff>

Git tracing shows nothing relevant as in the command above.

According to https://git-scm.com/docs/git-diff-tree adding --textconv should have respected the configured diff filter, but it does nothing.

Is this a bug or do I have something misconfigured?

Thank you.

git version 2.17.1