roachtest: fix crash on cluster creation failure

[andreimatei]

Before this patch, we'd segfault if cluster creation fails and we're running with --debug-always.

This patch is a small protection against the problem, but I don't think it's the right fix. The structure of the code makes similar bugs very likely to introduce -- I've made the same mistake myself. The issue is that, since #73706, the point where the cluster creation fails is disconnected from the point where that error is handled. It's very easy for code in between to assume that there is a cluster. Besides the bug being fixed here, there are some other awkward protections against a nil cluster around that seem surprising.

Epic: None Release note: None

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[andreimatei]

cc @srosenberg @DarrylWong

[srosenberg]

Before this patch, we'd segfault if cluster creation fails and we're running with --debug-always.

This patch is a small protection against the problem, but I don't think it's the right fix. The structure of the code makes similar bugs very likely to introduce -- I've made the same mistake myself. The issue is that, since #73706, the point where the cluster creation fails is disconnected from the point where that error is handled. It's very easy for code in between to assume that there is a cluster. Besides the bug being fixed here, there are some other awkward protections against a nil cluster around that seem surprising.

Thanks for the fix! Indeed, that code is overdue for restructuring. At some point, I'm still hoping to revisit a previous attempt [1].

[1] https://github.com/cockroachdb/cockroach/pull/101814

[DarrylWong]

bors r=srosenberg,darrylwong,herkolategan

[craig[bot]]

Build succeeded:

• acceptance
• macos_amd64_build
• linux_amd64_build
• local_roachtest
• examples_orms
• windows_build
• local_roachtest_fips
• linux_arm64_build
• lint
• docker_image_amd64
• unit_tests
• linux_amd64_fips_build
• check_generated_code
• macos_arm64_build