fix(lcb): expose sys.stdin.buffer so binary-stdin solutions are graded correctly#1256
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fix(lcb): expose sys.stdin.buffer so binary-stdin solutions are graded correctly#1256avalyset wants to merge 1 commit into
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The LiveCodeBench code grader patched sys.stdin with a StringIO, which has no .buffer, so a correct solution reading binary stdin (sys.stdin.buffer) raised AttributeError and was scored as failing. Replace the StringIO + per-method patches with a small stdin stand-in that preserves the exact text behaviour and additionally exposes .buffer. Add a regression test. Fixes huggingface#1255
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What
LiveCodeBench grades solutions by running them with
sys.stdinpatched to feed the test input. That patch was aStringIO, which has no.buffer— so any correct solution reading binary stdin viasys.stdin.buffer.read(), a common competitive fast-I/O idiom, raisedAttributeErrorinsidecall_methodand was scored as failing.Fix
Replace the
StringIO+ per-methodsys.stdin.read*patches with a small stand-in,_StdinWithBuffer, that keeps the existing text behaviour byte-for-byte (read/readline/readlines) and adds a.bufferbacked by aBytesIO. AStringIOcan't carry a.buffer(readonly C type), so a dedicated object is the minimal way to add binary stdin without touching the text path.Test
tests/unit/metrics/test_lcb_codegen_stdin.pyadds two cases: a solution readingsys.stdin.buffer(fails onmain, passes here) and one reading text stdin (unchanged). Both green;ruffclean.Fixes #1255