CI flake: internal compiler error building libssh

[clockwork-labs-bot]

Detected by CI Gremlin after a failed merge-queue run succeeded in a later merge-queue run without a new PR head commit.

Tests:

• TypeScript - Tests

Error:
error: failed to run custom build command for libssh2-sys v0.3.1
note: To improve backtraces for build dependencies, set the CARGO_PROFILE_DEV_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation.

Failed job runs:

• https://github.com/clockworklabs/SpacetimeDB/actions/runs/30316929206/job/90144405355 (TypeScript - Tests, attempt merge queue run 30316929206 -> merge queue run 30319055901)

Timeout detection:

• none

Context:

• Merge queue PR: Scheduled reducer: use timestamp from reducer params for next run #5574
• PR head SHA: 0935d32
• Later successful run: https://github.com/clockworklabs/SpacetimeDB/actions/runs/30319055901

[clockwork-labs-bot]

Diagnosis for the linked exact job/attempt:

• Public run/job: clockworklabs/SpacetimeDB run 30316929206, job 90144405355, TypeScript - Tests, attempt 1.
• Context from the ticket/run: merge queue for PR Scheduled reducer: use timestamp from reducer params for next run #5574, PR head SHA 0935d323c64d9efd576bdf210982b8f4d7047883; the failed merge-group run head SHA was 9aebf24d8a040268cb0549f2cfbc71fbe9e7c0e9.
• The job got past checkout and into the TypeScript test workflow. During the workflow's Rust build step, Cargo compiled libssh2-sys v0.3.1 and the C compiler failed while compiling libssh2/src/kex.c.
• Terminal signature:
  • internal compiler error: in try_forward_edges, at cfgcleanup.cc:580
  • source location: libssh2/src/kex.c:2373:1, function ecdh_sha2_nistp
  • error: failed to run custom build command for libssh2-sys v0.3.1
  • Error: Command failed: "cargo" ["build"] (exit exit status: 101)

Root cause for this exact attempt: the TypeScript test job failed before TypeScript test assertions because GCC internally crashed while compiling the vendored libssh2 C source used by libssh2-sys. This is a compiler/toolchain build flake in the merge-queue runner, not a TypeScript SDK test failure.

Suggested updated title:

CI build flake: TypeScript tests hit GCC ICE compiling libssh2-sys kex.c

Duplicate check in the Test Flakes tickets:

• I did not find an existing public or private Test Flakes ticket matching libssh2-sys v0.3.1 plus GCC internal compiler error: in try_forward_edges, at cfgcleanup.cc:580.
• CI flake: Smoketests (Linux) #5597, CI flake: Test Suite #5598, and CI flake: Keynote Bench #5599 are from the same failed merge-queue run, but those failed later in checkout because the merge-queue ref disappeared. They are not duplicates of this libssh2-sys compiler ICE.

Top duplicate candidate: none. Similar tickets in this batch exist for the same merge-queue run, but none are close enough to mark as duplicates of this compiler ICE.