🐛 Clear classical bits in resetSimulationState

[rturrado]

Description

🤖 AI text below 🤖

resetSimulationState in src/backend/dd/DDSimDebug.cpp rebuilt the quantum state on reset but left ddsim->variables (the map of classical bit values) untouched. After a first run followed by reset, reading c[k] returned the value from the previous run rather than the initial false, and the next measure on the same bit looked like a no-op because the bit already held the value it would receive.

This PR iterates ddsim->variables with std::ranges::for_each over std::views::values after the quantum state rebuild and sets each boolValue back to false, matching how the quantum side is reset. Includes an end-to-end test that runs a program, verifies c[0] is true, calls resetSimulation, and verifies c[0] is false.

AI assistance

Commit messages, code changes, and this PR body were drafted with Claude Opus 4.7 via Claude Code. All content was reviewed and edited manually before submission.

Fixes #464.

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

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[rturrado]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 061ec7d and e077116.

📒 Files selected for processing (2)

• src/backend/dd/DDSimDebug.cpp
• test/test_custom_code.cpp

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📝 Summary

Summary by CodeRabbit

• Bug Fixes

  • Resetting a simulation now also clears all classical variables, setting them to false alongside the quantum state.
  • This ensures classical measurement results do not persist after a simulation reset.

• Tests

  • Added coverage verifying that measured classical bits are cleared when the simulation is reset.

Walkthrough

The reset operation now clears all classical variables after rebuilding the quantum state. A regression test verifies that a measured classical bit returns to false.

Changes

Classical State Reset

Layer / File(s)	Summary
Reset classical variables and verify behavior src/backend/dd/DDSimDebug.cpp, test/test_custom_code.cpp	resetSimulationState sets every classical variable to false. The new test verifies this after a measurement.

Priority: ➖ Normal — Schedule the reset fix because it restores classical bits to false for the CLI reset command and adds regression coverage for this medium-severity issue.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to e0771

Simulation reset now restores classical bits to false alongside quantum state, with regression coverage confirming a measured true bit is cleared. The change is ready to merge.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The implementation resets all classical bit values to false after rebuilding the quantum state, and the added end-to-end test verifies this behavior. These changes satisfy issue #464 and remain within…
Out of Scope Changes check	✅ Passed	The source change and corresponding test are directly related to clearing classical bits during resetSimulationState. No unrelated changes are identified.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 2 files.
Title check	✅ Passed	The title clearly and concisely identifies the main change: clearing classical bits in resetSimulationState.
Description check	✅ Passed	The description explains the bug, motivation, implementation, linked issue, test coverage, AI assistance, and checklist status. It does not list dependencies explicitly, but this is non-critical and t…

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_{A rabbit measured one,
Then watched the reset run.
The quantum state turned new,
Classical bits did too.
False now waits in every slot.
Reset leaves no stale thought.}

_{Comment @coderabbitai help to get the list of available commands.}

[DRovara]

LGTM, thanks a lot! This is an interesting little slip.

Since we have been working on the VSCode integration of the Debugger that constantly displays the classical values, it's actually surprising that we never noticed this.