Tests: ExternalProject tests with git update command disabled are fragile
The change in !5741 (merged) exposed a weakness in the git test cases defined in
Tests/ExternalProject/CMakeLists.txt. If you run the tests for the commit just before that change was merged to master, the tests pass. Then update to the commit where !5741 (merged) was merged and re-run the tests again. The
ExternalProject test fails because it sees the repo has already been cloned and skips re-downloading again. Since the update commands have been disabled, the repo is not updated, but !5741 (merged) rewrote the history in the repo and so test logic that requires the new repo fails. The test output is long, but the steps described will reproduce the failures for anyone interested. Probably we need to explicitly clear anything created by a previous run of the
I'm creating this issue primarily as a marker to record where the problem first occurred. Further ongoing work on the ExternalProject module may otherwise mask the underlying cause.