rb_trilogy_connect: add GC guard for all string configs - #313
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Fix: trilogy-libraries#312 Since we're initializing `connopt` with pointers inside the user provided strings, we must ensure that they are pinned until we return from `rb_trilogy_connect`, otherwise if compaction happens concurrently, or another thread clears the `opts` hash, they could be guarbage collected or moved. To achieve that, every string option has an associated local variables that is guarded to ensure it isn't optimized out by the compiler.
Methods that take a string and release the GVL should handle concurrent modification of the string and concurrent compaction. For compaction the solution is to ensure they are pinned by virtue of being present on the stack, which is normally the case but compilers may optimize that out, so we should explictly use `RB_GC_GUARD`. As for concurrent modification, the intended API for that is `rb_str_locktmp` but it's quite incovenient to use when the method may raise, so a more ergonomic API is to acquire our own frozen copy with `rb_str_new_frozen`. That means an extra allocation but it's an acceptable tradeoff.
jeremy
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Aug 5, 2026
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Also noting that handle_trilogy_error is NORETURN and the guards sit after it… in principle the compiler could treat those VALUEs as dead on a branch that never reaches the guard. Kept live on the clang I checked, but leans on compiler behavior rather than a guarantee.
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Fix: #312
Since we're initializing
connoptwith pointers inside the user provided strings, we must ensure that they are pinned until we return fromrb_trilogy_connect, otherwise if compaction happens concurrently, or another thread clears theoptshash, they could be guarbage collected or moved.To achieve that, every string option has an associated local variables that is guarded to ensure it isn't optimized out by the compiler.