`./tools/dope./sh` fails for MacOS

[FranjoMindek]

I've followed readme's MacOS instructions for opensaas-sh but running the patch.sh fails when it calls the dope.sh script.

Error message:

patch: unrecognized option `--merge'
usage: patch [-bCcEeflNnRstuv] [-B backup-prefix] [-D symbol] [-d directory]
             [-g vcs-option] [-F max-fuzz] [-i patchfile] [-o out-file]
             [-p strip-count] [-r rej-name] [-T | -Z]
             [-V t | nil | never | none] [-x number] [-Y prefix]
             [-z backup-ext] [--quoting-style style] [--posix]
             [origfile [patchfile]]
       patch <patchfile

[Failed with exit code 1]

On my latests favicon changes PR I'm doing I tried to just remove the flag, it didn't break anything:

        patch_output=$(patch --no-backup-if-mismatch --merge "${DERIVED_DIR}/${derived_filepath}" < "${diff_filepath}")

->

        patch_output=$(patch --no-backup-if-mismatch "${DERIVED_DIR}/${derived_filepath}" < "${diff_filepath}")

Though, that might not be case for all situations.
We need to explore an alternative.

[Martinsos]

@vincanger uses dope.sh a lot on Mac and had some trouble but fixed it, he will know more probably! Or you should at least compare your setups, to see what is the difference.

[infomiho]

@FranjoMindek did you follow the README and installed the Mac specific packages? What versions do you have for those packages?

Here are mine:

gpatch --version
GNU patch 2.8
diff -version
diff (GNU diffutils) 3.10
realpath --version
realpath (GNU coreutils) 9.5

[FranjoMindek]

Yep, followed all of them:

➜  ~ gpatch --version
GNU patch 2.8
➜  ~ diff -version
diff (GNU diffutils) 3.12
➜  ~ realpath --version
realpath (GNU coreutils) 9.7

[infomiho]

For me, it broke down as well. I diagnosed it to be because the script didn't pick up my alias defined in .zshrc. I verified that by running patch --version from the script. It said that I'm using the built in patch and not GNU patch.

Doing something like this helped:

PATCH_CMD="patch"
if [[ "$(uname)" == "Darwin" ]]; then
    # We're on macOS, check if gpatch exists
    if command -v gpatch &> /dev/null; then
        PATCH_CMD="gpatch"
    fi
fi

[FranjoMindek]

Explore a bit and confirmed "Aliases and functions do not propagate to shell scripts. This is by design".
We will need to handle OS differences in the script itself.