Don't crash when consuming arbitrary random data. - #210
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[scratchpad] Fix crash: VPA/DSR under DECOM without scrolling margins (Bug D)
org-ai-assisted/pyte#3
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- erase_in_line and erase_in_display bind `interval` only for the `how` values they handle, then use it unconditionally. Any other value leaves it unbound -> UnboundLocalError out of Stream.feed(). - Stream passes CSI parameters through unvalidated, so any `how` in 3..9999 is reachable from untrusted terminal output. That crashes the hosting application on `cat` of arbitrary binary data. - Add an `else: return` to both, matching how a real terminal ignores an erase mode it does not implement. Regression test: tests/test_screen.py::test_erase_unhandled_how_is_a_noop, covering both direct calls and the end-to-end parser path. Verified 1 fail on the pre-fix code (UnboundLocalError at screens.py:792), 118 pass / 0 fail / 0 skip / 1 xfail on the fix. Tracked as Bug C in org-ai-assisted/pyte-audit; CodeQL flags the same two sites as py/uninitialized-local-variable. Upstream PR selectel#210 fixes this class with an identical `else: return`, so this is not for upstream submission. Style follows upstream pyte (comment style, test layout), not the org convention, per the fork rule. Co-Authored-By: Claude <noreply@anthropic.com>
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Right now, when consuming random, invalid ANSI escape codes, the parser crashes.
See: #209
This PR ensures that the parser never crashes.
(It would be nice if we could verify this statically through a type checker, but that's probably not feasible without breaking changes, and a lot more work.)