Supporting RooUtil in Dask

[AndrewEdmonds11]

This PR adds a roodask.py script for running RooUtil macros using dask. This is mostly vibe-coded with Claude Opus 4.6. There is a README (generated by the AI).

[AndrewEdmonds11]

Prompt: "Please review this PR for critical bugs"
Model: Claude Sonnet 4.6
Output:

Here's a review of critical bugs found in rooutil/roodask/roodask.py:

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🐛 Critical Bugs

1. TypeError in hadd_target path resolution

File: roodask.py, in the hadd section of main()

hadd_target = Path(args.hadd)
if not hadd_target.is_absolute():
    hadd_target = output_dir / hadd_target  # ❌ BUG

Problem: output_dir is a str (set via str(Path(...).resolve()) earlier), not a Path. The / operator only works when the left-hand side is a Path. This will raise a TypeError: unsupported operand type(s) for /: 'str' and 'PosixPath' at runtime whenever --hadd is given a relative path.

Fix:

hadd_target = Path(output_dir) / hadd_target

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2. work_dir inconsistency between submitter and workers

File: roodask.py, in client.submit(...) call

work_dir=args.work_dir,   # ❌ passes the raw/relative CLI string

Problem: args.work_dir is passed as-is (e.g. "./work") to the workers, but the resolved work_dir (a Path) is what the submitter uses locally. On a shared filesystem this is fine if workers share the CWD, but if workers resolve paths differently or the scheduler runs from a different CWD, per-job filelist files will be written to the wrong location (or fail to be found by the binary). The resolved absolute path should be passed instead.

Fix:

work_dir=str(work_dir),   # work_dir is already resolved to an absolute Path

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3. --skip-compile / --force-compile mutual exclusion not enforced

File: roodask.py, parse_args()

Problem: Both --skip-compile and --force-compile can be specified simultaneously. Their combination is contradictory, and the code gives no error. Whichever branch is checked first (skip_compile is checked before force_compile) will silently "win" — --skip-compile takes priority and --force-compile is silently ignored, which is surprising and potentially confusing.

Fix: Add a mutual-exclusion check after parse_args():

if args.skip_compile and args.force_compile:
    print("ERROR: --skip-compile and --force-compile are mutually exclusive", file=sys.stderr)
    sys.exit(1)

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4. Stale config_template.txt references removed concept

File: rooutil/roodask/config_template.txt

The copilot instructions file explicitly states: "config_template field was removed — the script generates the wrapper automatically". However, config_template.txt is still committed. It won't break execution, but it's dead/confusing artifact that the AI generated and forgot to clean up.

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⚠️ Minor Issues (non-critical)

• import math is placed mid-function (after reading the filelist). While valid Python, it's against convention and should be at the top of the file with the other imports.
• "Error" stderr check is fragile: Any job that prints "Error" to stderr (e.g. a normal ROOT warning that contains the word) will be marked as failed, including messages like TError: no error. A regex check like re.search(r'\bError\b', ...) might be more precise.
• No validation that source file actually exists before attempting compilation — a missing file would result in a cryptic g++ error rather than a clear message.

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The most urgent fix is bug #1 — it will always crash when --hadd is given a relative path. Bug #2 is important for correctness in distributed (non-local) scheduler setups.

[AndrewEdmonds11]

Fixed bugs found by Copilot. Also added a validation script with example commands. Merging now...