fix: extension registration uses original AWS_LAMBDA_RUNTIME_API#737
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apply_runtime_proxy_config() overwrites AWS_LAMBDA_RUNTIME_API with the proxy address before the Adapter is created. register_extension_internal() then read the overwritten value, so extension register/next calls were sent through the proxy instead of the real Lambda Runtime API. Capture the original value in a process-wide OnceLock before the overwrite and prefer it in register_extension_internal(). No public API change.
seshubaws
reviewed
May 27, 2026
When apply_runtime_proxy_config() runs with AWS_LAMBDA_RUNTIME_API unset, ORIGINAL_LAMBDA_RUNTIME_API holds Some(None). The previous fallback chain collapsed Some(None) and None together, so the code fell through to env::var() — which by that point had been overwritten to the proxy address, defeating the fix. Use a match to keep the two cases distinct: when capture happened, never read the (now-overwritten) env var.
seshubaws
approved these changes
May 27, 2026
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Summary
Adapter::apply_runtime_proxy_config()overwritesAWS_LAMBDA_RUNTIME_APIwith the proxy address before the adapter is constructed.register_extension_internal()then read the (overwritten) env var, so extensionregisterandevent/nextcalls were routed through the proxy instead of the real Lambda Runtime API.AWS_LAMBDA_RUNTIME_APIvalue in a process-wideOnceLock<Option<String>>before the overwrite, and prefer it inregister_extension_internal(). Falls back to the env var (and then127.0.0.1:9001) when no original was captured.Test plan
cargo build --libcargo test --lib— 21/21 passtest_apply_runtime_proxy_configextended to assert the captured original value (folded into one test because theOnceLockis process-wide and only settable once)