Fix param expansion in inherited environment.

[hjoliver]

These changes close #4242

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• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• No dependency changes.
• Appropriate tests are included (extended an existing functional test).
• Appropriate change log entry included.
• No documentation update required (this branch conforms to advertised behaviour).

[hjoliver]

This is ready to go now.

[kinow]

Code and tests look good! Pending only CI to pass 👍

[kinow]

mypy error fixed in the merged #4251

[hjoliver]

Rebased.

[kinow]

@hjoliver can we ignore the macos failure?

2021-06-09T01:59:36.3004720Z TOTAL                                                20623   7211   8643      0    75.36%
2021-06-09T01:59:36.3005000Z 
2021-06-09T01:59:36.3005400Z =========================== short test summary info ============================
2021-06-09T01:59:36.3006860Z FAILED tests/integration/test_scan.py::test_scan_sigstop - AssertionError: as...
2021-06-09T01:59:36.3007580Z ================== 1 failed, 86 passed, 24 warnings in 33.58s ==================

2021-06-09T01:59:36.2794800Z E           AssertionError: assert [(20, '[one.1...05056910e93')] == [(30, 'Workfl...05056910e93')]
2021-06-09T01:59:36.2796570Z E             At index 0 diff: (20, '[one.1] -released from runahead') != (30, 'Workflow not running: 46dcaa6a-c8c6-11eb-8e68-005056910e93')
2021-06-09T01:59:36.2798370Z E             Left contains one more item: (30, 'Workflow not running: 46dcaa6a-c8c6-11eb-8e68-005056910e93')
2021-06-09T01:59:36.2799580Z E             Full diff:
2021-06-09T01:59:36.2800190Z E               [
2021-06-09T01:59:36.2800750Z E             +  (20,
2021-06-09T01:59:36.2801840Z E             +   '[one.1] -released from runahead'),
2021-06-09T01:59:36.2802600Z E                (30,
2021-06-09T01:59:36.2803850Z E                 'Workflow not running: 46dcaa6a-c8c6-11eb-8e68-005056910e93'),
2021-06-09T01:59:36.2804740Z E               ]

[hjoliver]

Yeah that MacOS scan test is failing on most PRs now, nothing to do with this change.

Issue for it: #4243

And ... the fix just got merged minutes ago: #4244

I'll rebase this again

[oliver-sanders]

Sadly this didn't work for my example workflow, took a bit of staring before I found the edge case that was causing the bug.

On this branch the following example fails:

[task parameters]
    a = 1..3
    b = 1

[scheduling]
    [[graph]]
        R1 = x<b>

[runtime]
    [[FAM<a>]]
        [[[environment]]]
            param = %(a)s

    [[x<b=1>]]
        inherit = FAM<a=1>
        script = test $param -eq 1

    [[x<b>]]
        pre-script = echo pre

However, if you comment out the last task:

    # [[x<b>]]
    #    pre-script = echo pre

It will pass on this branch (but not on master).

[hjoliver]

God damn it. Sadly indeed!

[hjoliver]

It certainly works for your original example, on #4242

[hjoliver]

Interestingly, it works if I swap the order:

    [[x<b>]]
        pre-script = echo pre

    [[x<b=1>]]
        inherit = FAM<a=1>
        script = test $param -eq 1

[hjoliver]

Fixed now, and test extended to cover this case.

[oliver-sanders]

My example now passes, thanks.