Guard string VALUEs while parsing their C string - #556
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StringValueCStr may replace the local VALUE with the result of to_str, leaving the converted String referenced only from a C local. VpAlloc allocates a temporary buffer with rb_str_tmp_new before it scans the C string, so a GC triggered there could free the String while its contents are still being read. Add RB_GC_GUARD after the last use of the pointer in the three places that parse a String argument. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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StringValueCStrmay replace the local VALUE with the result ofto_str, leaving the converted String referenced only from a C local.VpAllocallocates a temporary buffer withrb_str_tmp_newbefore it scans the C string, so a GC triggered there could free the String while its contents are still being read.This adds
RB_GC_GUARDafter the last use of the pointer in the three places that parse a String argument:rb_str_convert_to_BigDecimal(BigDecimal(obj)with ato_strobject)BigDecimal_s_interpret_loosely(String#to_d)BigDecimal_loadWith the current compiler output the VALUE happens to stay in a stack slot that the conservative GC scans, so this is not reproducible today, but it depends on register/stack allocation choices rather than on anything guaranteed.
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