Preserve explicit ground connections instead of redundant GND branches

[imrishabh18]

Context

The PGA300 reproduction from #930 is now merged into main. This PR is rebased onto the latest main (5091d2f) and contains one fix commit.

The global ground spanning tree was replacing the circuit's explicit PGA300 COMP–R1 ground wire with two unnecessary branches: COMP–U1.GND and COMP–C3.

Fix

• Extend the existing getGroundConnectionPolicy path used by both the MSP and long-distance solvers.
• For nets explicitly marked isGround, preserve physical islands defined by explicit pin-to-pin traces.
• Treat label-only ground pins as separate physical islands and connect those islands electrically through labels rather than new routed traces.
• Prevent long-distance recovery from recreating the redundant ground branches.
• Keep existing automatic ground-bus behavior for unannotated nets and marked ground nets without explicit wires.
• Avoid circuit-specific pin IDs or coordinates in production code.

The full-circuit regression now requires the explicit COMP–R1 connection, rejects both redundant branches, verifies all source GND pins remain electrically connected through traces and labels, and preserves the vertical Q1–R1 connection.

Before / after

Before — merged reproduction

After — generated by this PR

Validation

• bun test: 280 passed, 4 existing skips, 0 failures
• bunx tsc --noEmit
• bun run build
• Focused Biome formatting check
• git diff origin/main...HEAD --check

All checks above pass.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
schematic-trace-solver	Ready	Preview	Aug 27, 2026 12:34pm

[tscircuitbot]

---

Thank you for your contribution! 🎉

PR Rating: ⭐⭐⭐
Impact: Major

Track your contributions and see the leaderboard at: tscircuit Contribution Tracker

---