  As the adoption of proof assistants increases, there is a need for efficiency
in identifying, documenting, and fixing compatibility issues that arise from
proof assistant evolution. We present the Coq Bug Minimizer, a tool for
reproducing buggy behavior with minimal and standalone files, integrated with
coqbot to trigger automatically on Coq reverse CI failures. Our tool eliminates
the overhead of having to download, set up, compile, and then explore and
understand large developments: enabling Coq developers to easily obtain modular
test-case files for fast experimentation. In this paper, we describe insights
about how test-case reduction is different in Coq than in traditional
compilers. We expect that our insights will generalize to other proof
assistants. We evaluate the Coq Bug Minimizer on over 150 CI failures. Our tool
succeeds in reducing failures to smaller test cases in roughly 75% of the time.
The minimizer produces a fully standalone test case 89% of the time, and it is
on average about one-third the size of the original test. The average reduced
test case compiles in 1.25 seconds, with 75% taking under half a second.
