ci-wrapper: grep for errors at the end

dev/ci/ci-wrapper.sh

@@ -17,5 +17,21 @@ export TIMED=1
 bash "${DIR}/${CI_SCRIPT}" 2>&1 | tee "$CI_NAME.log"
 code=$?
 echo 'Aggregating timing log...'
+echo
 python ./tools/make-one-time-file.py --real "$CI_NAME.log"
+if true || ! [ $code = 0 ]; then
+  echo
+  echo "Error list (may be incomplete):"
+
+  # -P: perl-like
+  # -z: multiline using \0 chars (which is why we have to tr to cleanup the output)
+  # -o: print only matched (otherwise it prints the whole file due to -z)
+  # Pattern:
+  # - File ".*
+  # - maybe some lines starting with a number and a line containing only spaces and ^ (ocaml errors)
+  # - the error line (common between ocaml and coq)
+  # we only get the first line of the error message (too hard to figure out where it ends)
+  # || true: if the error isn't matched by this pattern, we still want to use the error code from the build
+  grep -Pzo 'File ".*\n([0-9].*\n)*([ ^]*\n)?Error.*\n' "$CI_NAME.log" | tr -d '\0' || true
+fi
 exit $code