Trust diffblue/cbmc tap so macOS Kani CI survives Homebrew 6.0+ - #688
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feliperodri merged 1 commit intoSep 17, 2026
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Homebrew 6.0 began refusing to load formulae from untrusted third-party taps, so the pinned Kani's scripts/setup/macos/install_cbmc.sh fails at `brew tap diffblue/cbmc`, leaving CBMC uninstalled and every macOS Kani job broken (e.g. `[Errno 2] No such file or directory: 'cbmc'`). Run `brew trust diffblue/cbmc` before invoking the macOS setup script so CBMC installs regardless of the Kani commit currently pinned. Mirrors the upstream fix model-checking/kani#4785 without requiring a toolchain bump. Guarded with `2>/dev/null || true` for older Homebrew lacking `brew trust`.
rajath-mk
approved these changes
Sep 17, 2026
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Problem
Homebrew 6.0 started refusing to load formulae from untrusted third-party taps. The pinned Kani's
scripts/setup/macos/install_cbmc.shrunsbrew tap diffblue/cbmc, which now fails onmacos-latestrunners, so CBMC never gets installed and every macOS Kani job dies with:This is currently red on all macOS jobs (see #685), and the fail-fast cancellation also takes down the ubuntu counterparts.
Fix
Run
brew trust diffblue/cbmc 2>/dev/null || trueinrun-kani.shright before it invokes the macOS setup script, so the tap is trusted before Kani taps it — regardless of which Kani commit is pinned. The guard makes it a no-op on older Homebrew that lacksbrew trust.This mirrors the upstream Kani fix model-checking/kani#4785, applied at the verify-rust-std layer so it does not require bumping the pinned Kani commit / toolchain.
Testing
Ubuntu path is unchanged; macOS CI on this PR exercises the fix.