fix: naive use of cstring pointer as a typed array buffer pointer resulting in a crash on gc in #739 - expose stringToBuffer#740
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saghul merged 10 commits intosaghul:masterfrom Jan 21, 2026
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…resulting in a crash on gc
saghul
approved these changes
Jan 21, 2026
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This is a fix for #739 . My assumption was that JS_ToCString was returning c managed memory buffer - so handing it over to the js runtime by using it as a backing buffer for a typed array would be fine.. but as it turns out JS_ToCString do actually return a memory buffer to a cstring, BUT this buffer is actually already a backing buffer of a JSString allocated in this function.. so GCing the JSString and the TypedArray resulted in double free and a crash. So the updated code now
This time I did my homework (hopefully) - I tested the code both for stability and if it is leaking memory with the help of
JS_SetDumpFlags(rt, JS_DUMP_LEAKS); JS_SetDumpFlags(rt, JS_DUMP_MEM);andENABLE_DUMPS- no difference in memory usage at the end of a test after no calls vs 10.. 100.. and 1000 calls toffi.bufferToString(ffi.stringToBuffer(longString)and no leaked objects and strings reported.