[johnnyreilly]

Summary

Removes the temporary fallback added in #1712. When the benchmark job's base branch had no package-lock.json, it installed that base with npx yarn@1. The fallback only existed so #1712's own benchmark could install the pre-migration main.

main now has package-lock.json, so every PR's base installs with plain npm ci, and the yarn branch can no longer be reached.

Testing

This PR's own benchmark job exercises the change, since its base is the post-migration main.

🤖 Generated with Claude Code

[github-actions]

Benchmark (Ubuntu)

Scenario	transpileOnly	PR branch median (ms)	base branch median (ms)	Δ vs base branch
Cold build	false	947.7	942.2	+0.6%
Incremental rebuild (leaf touch)	false	59.7	59.6	+0.2%
Incremental rebuild (hub touch)	false	370.4	368.5	+0.5%
Cold build	true	537.3	548.0	-2.0%
Incremental rebuild (leaf touch)	true	32.7	31.7	+3.2%
Incremental rebuild (hub touch)	true	32.1	32.9	-2.5%

PR branch = /home/runner/work/ts-loader/ts-loader, base branch = /home/runner/work/ts-loader/ts-loader-main. 2 warmup + 10 measured iterations per scenario, median reported. Report-only - no threshold fails this check.

[github-actions]

Benchmark (macOS)

Scenario	transpileOnly	PR branch median (ms)	base branch median (ms)	Δ vs base branch
Cold build	false	888.0	890.8	-0.3%
Incremental rebuild (leaf touch)	false	98.5	99.2	-0.7%
Incremental rebuild (hub touch)	false	429.7	426.1	+0.8%
Cold build	true	557.0	560.6	-0.6%
Incremental rebuild (leaf touch)	true	56.6	58.7	-3.6%
Incremental rebuild (hub touch)	true	58.4	56.9	+2.5%

PR branch = /Users/runner/work/ts-loader/ts-loader, base branch = /Users/runner/work/ts-loader/ts-loader-main. 2 warmup + 10 measured iterations per scenario, median reported. Report-only - no threshold fails this check.

[github-actions]

Benchmark (Windows)

Scenario	transpileOnly	PR branch median (ms)	base branch median (ms)	Δ vs base branch
Cold build	false	1343.7	1314.4	+2.2%
Incremental rebuild (leaf touch)	false	76.7	74.7	+2.7%
Incremental rebuild (hub touch)	false	552.4	535.7	+3.1%
Cold build	true	866.4	835.8	+3.7%
Incremental rebuild (leaf touch)	true	48.1	48.4	-0.5%
Incremental rebuild (hub touch)	true	48.6	47.6	+2.1%

PR branch = C:\source\ts-loader, base branch = C:\source\ts-loader-main. 2 warmup + 10 measured iterations per scenario, median reported. Report-only - no threshold fails this check.