unwrapped DAGCircuit::collect_runs() to not return an Option

[cameron-d28]

Summary

This change updates the collect_runs function to return a PyResult instead of an Option so that error can be routed by to DAGCircuit when invalid states are present.

Details and comments

fixes #13109

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[kevinhartman]

Thanks for the contribution, @cameron-d28!

This looks like a good start. I've left a few comments inline, primarily regarding the way we ought to handle the cycle error case. After addressing that, you'll need to adjust py_collect_runs as well for the new return type.

[cameron-d28]

thank you for the feedback @kevinhartman! i have improved my changes. please let me know how they look 🙂

[kevinhartman]

Thanks for the updates, @cameron-d28!

This is looking good to me now. I like the change you made to use a single for-loop rather than a map followed by a for-loop when adding runs to the out_set in DAGCircuit::py_collect_runs.

[coveralls]

Pull Request Test Coverage Report for Build 11077292777

Details

• 14 of 15 (93.33%) changed or added relevant lines in 2 files are covered.
• 5 unchanged lines in 2 files lost coverage.
• Overall coverage remained the same at 88.883%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/circuit/src/dag_circuit.rs	12	13	92.31%

Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/expr.rs	1	94.02%
crates/qasm2/src/lex.rs	4	92.98%

Totals
Change from base Build 11076723215:	0.0%
Covered Lines:	74138
Relevant Lines:	83411

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💛 - Coveralls

[cameron-d28]

glad to see the update made sense @kevinhartman! i didn't see why the mapping would still be needed - (maybe for lazy eval?? not sure).