tls: add CHECK for impossible condition

Backport-PR-URL: #27967 PR-URL: #26843 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Minwoo Jung <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>

Author: addaleax

src/tls_wrap.cc

@@ -680,10 +680,10 @@ void TLSWrap::OnStreamRead(ssize_t nread, const uv_buf_t& buf){
 return;
  }
 
-if (ssl_ == nullptr){
-EmitRead(UV_EPROTO);
-return;
-}
+// DestroySSL() is the only thing that un-sets ssl_, but that also removes
+// this TLSWrap as a stream listener, so we should not receive OnStreamRead()
+// calls anymore.
+CHECK(ssl_);
 
 // Commit the amount of data actually read into the peeked/allocated buffer
 // from the underlying stream.