./bin/build.sh does not automatically set ROOT_DIR outside of tipc directory

[thepetertessier]

I don't know if this counts as a "bug", but when using build.sh outside of the tipc directory, I get the strange error message:

fatal: not a git repository (or any parent up to mount point /u)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

See the full example of what I'm getting (on portal, after the aforementioned git pull):

# Just entered portal, go to my desired directory and load the module:
fpv5gr@portal10:~$ cd CS_4620/
fpv5gr@portal10:~/CS_4620$ module load /u/fpv5gr/CS_4620/tipc/conf/modulefiles/tipc/F24
Loading /u/fpv5gr/CS_4620/tipc/conf/modulefiles/tipc/F24
  Loading requirement: /u/fpv5gr/CS_4620/tipc/conf/modulefiles/java/11 clang-llvm-17.0.6 cmake-3.26.4

# An example tip program:
fpv5gr@portal10:~/CS_4620$ cat exercise_01/hello.tip
main(x) {
    return x+13;
}

# I try to use build.sh outside of tipc:
fpv5gr@portal10:~/CS_4620$ tipc/bin/build.sh exercise_01/hello.tip
fatal: not a git repository (or any parent up to mount point /u)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

# I try again, inside of tipc:
fpv5gr@portal10:~/CS_4620$ cd tipc/
fpv5gr@portal10:~/CS_4620/tipc$ bin/build.sh ../exercise_01/hello.tip

# No error message now, and indeed it worked:
fpv5gr@portal10:~/CS_4620/tipc$ ./hello 1
Program output: 14

I believe this is due to line 5 of build.sh:

ROOT_DIR=${TIPDIR:-$(git rev-parse --show-toplevel)}

If I still want to run build.sh outside of the tipc directory, I can just export TIPDIR=.../tipc. However, I had to do some digging to figure this out. Perhaps we can add some validation before setting ROOT_DIR, such as:

# Check if we can set the ROOT_DIR as TIPDIR or as the root of the git repo
if [ -z "${TIPDIR}" ] && ! git rev-parse --is-inside-work-tree > /dev/null 2>&1; then
    echo "error: Not in a git repository and TIPDIR is not set. Please export TIPDIR=.../tipc"
    exit 1
fi

That will at least make the issue more diagnosable for the user.

The method of automatically setting ROOT_DIR based on what git repo we are in could have another potential problem of quietly setting it to another git repo we are currently in. But perhaps for the scope of this project, it is fine to assume this edge case won't happen.

[thepetertessier]

Related, I see that tipc/bin/cleancov.sh uses GITHUB_WORKSPACE instead of TIPDIR:

ROOT_DIR=${GITHUB_WORKSPACE:-$(git rev-parse --show-toplevel)}

It seems like all the other files in bin use GITHUB_WORKSPACE as well, so for consistency, TIPDIR in build.sh should probably change to GITHUB_WORKSPACE. That way, if a user wants to set that variable manually, they only have to set GITHUB_WORKSPACE, not TIPDIR as well. If this change is made, the README's in tipc and tipc/bin would have to be updated as well to change TIPDIR to GITHUB_WORKSPACE.