catch CI job name / Coq version mismatches

prepare-opam.sh

@@ -82,6 +82,14 @@ while (( "$#" )); do # while there are arguments left
     status "[prepare-opam] $KIND-pinning $PACKAGE to $VERSION"
     opam pin add -y -n -k "$KIND" "$PACKAGE" "$VERSION"
     PINNED_PACKAGES="$PINNED_PACKAGES $PACKAGE"
+
+    # Special treatment for "coq" package: make sure its version matches the CI job name.
+    if [[ "$PACKAGE" == "coq" ]]; then
+        # If the job name contains `coq.SOMETHING` but not `coq.$VERSION`, then it is wrong.
+        if fgrep -q -- "-coq." <<<"$CI_JOB_NAME" && ! fgrep -q -- "-coq.$VERSION" <<<"$CI_JOB_NAME"; then
+            panic "CI job name ($CI_JOB_NAME) does not match Coq version ($VERSION)"
+        fi
+    fi
 done
 echo