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SyntaxError: Unexpected end of JSON input
after POST /rest/api/3/issue/{key}/transitions (also POST /rest/agile/1.0/backlog/issue and most PUTs); the request itself succeeded with 204
Cause
those endpoints answer 204 No Content with an empty body, so calling res.json() on the Response throws even though the write went through.
Fix
-const body = await res.json();+if (res.status === 204) return null; // success with an empty body: nothing to parse+const body = await res.json();Don’t try
catch the parse error and treat it as a failed request — the write already succeeded; compensating logic then runs against a success (here it deleted a loop guard and started an infinite revert loop).