Bug 1787398 - Prevent use-sccache to be set when use-pgo is set. r=taskgraph-reviewers,jmaher

Differential Revision: https://phabricator.services.mozilla.com/D156037

taskcluster/gecko_taskgraph/transforms/build.py

@@ -178,6 +178,11 @@ def use_profile_data(config, jobs):
             # LTO linkage needs more open files than the default from run-task.
             job["worker"]["env"].update({"MOZ_LIMIT_NOFILE": "8192"})
 
+        if job.get("use-sccache"):
+            raise Exception(
+                "use-sccache is incompatible with use-pgo in {}".format(job["name"])
+            )
+
         yield job