fix: validate contact surface parameters to prevent LCP solver crashes (DART 7)

[jslee02]

Summary

• Add validation for NaN/Inf/negative friction, restitution, and slip compliance values in ContactSurface and SoftContactConstraint
• Invalid values now log a warning and fall back to defaults, preventing assertion failures in the LCP solver

Problem

When malformed SDF files contain invalid friction values (e.g., <mu>NaN</mu>), these propagate through DART's constraint system and cause an assertion failure in dSolveLCP:

lo[k] <= 0 && hi[k] >= 0

This crashes simulations in gz-physics and any other downstream consumers.

Solution

Validate contact surface parameters at extraction time in:

• DefaultContactSurfaceHandler::computeFrictionCoefficient()
• DefaultContactSurfaceHandler::computePrimaryFrictionCoefficient()
• DefaultContactSurfaceHandler::computeSecondaryFrictionCoefficient()
• DefaultContactSurfaceHandler::computePrimarySlipCompliance()
• DefaultContactSurfaceHandler::computeSecondarySlipCompliance()
• DefaultContactSurfaceHandler::computeRestitutionCoefficient()
• SoftContactConstraint::computeFrictionCoefficient()
• SoftContactConstraint::computeRestitutionCoefficient()

Invalid values are rejected with a warning and replaced with safe defaults.

Testing

• Added 21 new unit tests covering NaN, Inf, negative, and valid value cases
• All 137 existing tests pass
• LCP solver benchmarks show no performance regression

Related Issues

Related to gazebosim/gz-physics#841

Checklist

• Code compiles without errors
• All tests pass
• Added new tests for the fix
• Updated CHANGELOG.md

[codecov]

Codecov Report

❌ Patch coverage is 58.82353% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.49%. Comparing base (a15166f) to head (12529fc).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
dart/constraint/SoftContactConstraint.cpp	0.00%	10 Missing ⚠️
dart/constraint/ContactSurface.cpp	83.33%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2434   +/-   ##
=======================================
  Coverage   66.49%   66.49%           
=======================================
  Files         407      407           
  Lines       37254    37278   +24     
  Branches     4901     4906    +5     
=======================================
+ Hits        24772    24788   +16     
- Misses      12482    12490    +8     

Flag	Coverage Δ
unittests	66.49% <58.82%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
dart/constraint/ContactSurface.cpp	86.13% <83.33%> (+1.00%)	⬆️
dart/constraint/SoftContactConstraint.cpp	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

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[jslee02]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Can't wait for the next one!

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[jslee02]

@codex review

This PR has been rebased on main to incorporate the new error handling infrastructure from #2445. The validation approach using DART_WARN with fallback to default values is appropriate for this use case (expected failures from malformed SDF data).

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep them coming!

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

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