On macOS (arm64) Tectonic 0.15.0 insists on writing to $HOME/Library/Caches/Tectonic after setting $TECTONIC_CACHE_DIR

[anjos]

The title says it all. Is this to be expected or is it an issue? For info, I'm using the build from conda-forge.

Reproducing:

1. Move or remove $HOME/Library/Caches/Tectonic
2. Re-create that directory and remove permissions mkdir $HOME/Library/Caches/Tectonic && chmod u-w $HOME/Library/Caches/Tectonic
3. export TECTONIC_CACHE_DIR=.cache-tectonic
4. Compile a document in the current directory

Output is:

export TECTONIC_CACHE_DIR=.cache-tectonic && tectonic -X compile test.tex
note: "version 2" Tectonic command-line interface activated
error: Permission denied (os error 13)
caused by: Permission denied (os error 13)

If I enable writing on $HOME/Library/Caches/Tectonic, the problem goes away, however Tectonic still writes a file inside that location:

tree ~/Library/Caches/Tectonic
/Users/andre/Library/Caches/Tectonic
└── formats
    └── 6ffe055852f8faf66c0acbe1a7fb27f87b869a90bad1204f3bf4d9683f597c7c-latex-33.fmt

2 directories, 1 file