GitHub Issues search now supports nested queries and boolean operators: Here's how we (re)built it

GitHub has enhanced its Issues search functionality by introducing advanced search syntax that allows users to construct queries using logical AND/OR operators and nested parentheses, enabling more precise search results. This upgrade required replacing the existing search module with a new one capable of handling nested queries while ensuring backward compatibility and maintaining performance. The transition involved parsing user input into an Abstract Syntax Tree (AST) and transforming it into an Elasticsearch query document, allowing for complex query structures without degrading performance or user experience. The development process included extensive testing, internal trials, and gradual rollouts to minimize risk, ensuring that longstanding user requests were met while preserving existing functionality.