The EINTR loop around getline was added to fix an issue with mac gdb, but seems
to loop infinitely in rare cases on linux where the parent editor exits (most
reports with VSCode).
I can't work out how to fix this in a portable way with std::istream, but the
C APIs have clearer contracts and LLVM has a RetryAfterSignal function for use
with them which seems battle-tested.
While here, clean up some log() usages to avoid double-newlines (except after large JSON payloads)