docker-entrypoint.sh uses a .sh file's executable mode to decide whether to source or exec the shell script. Due to a long-standing issue on Docker Desktop for macOS when VirtioFS or gRPC FUSE are used all files mounted into the container from the host are executable according to test -x even if the executable bit is not set, so this test is unreliable. As a result non-executable scripts in /docker-entrypoint-initdb.d are executed, giving a Permission denied error and the script does not run.

Although this really needs fixing in Docker Desktop, it's potentially going to lead to hard-to-diagnose issues in Postgres initialisation so I thought it at least worth reporting here for visibility. A possible workaround for the Docker issue could be to use stat and grep: something like if stat -c '%A' "$f" | grep -q '^-..x'; then ....