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RUNTIME-005: Binary file write mode ('wb') not supported — no byte array type #170
Description
Activity
Triage 2026-08-17 (against v5.0.2). Still reproduces — there is no binary write path:
$ nodus run b1.nd Key error: Missing module export: write_bytesstd:fsexposes nowrite_bytes, and there is still no byte-array type.
Unchanged through 5.0.2.Re-verified 2026-08-30 against 5.7.1 dev source — still valid, as part of a sweep over the 2026-06-07 audit batch.
No
write_file_bytes/read_file_bytesbuiltin exists, and there is still no byte type. Every"wb"open in the tree is internal Python —bytecode_cache.py,snapshots.py,registry_client.py,subprocess_module.py— and none is reachable from.nd.Still the bootstrap gap this describes:
examples/expr_compiler.ndis a lexer/parser/evaluator already written in Nodus, and it cannot write its output.Cross-reference for whoever picks this up: #173, the other named blocker on the same axis, has moved — throughput measured ~477K instr/sec after #522, roughly double the figure still in that issue's title. This one has not moved at all.
- added a commit that references this issue
on Aug 31, 2026 - added a commit that references this issue
on Sep 1, 2026
Summary
builtin_write_fileinio.pyalways opens files withencoding='utf-8'— there is no binary write mode. Scripts that need to write binary data (compiled bytecode, image files, protocol buffers) cannot do so viastd:fs.Additionally, there is no byte array type in Nodus. Binary data from
subprocess.stdoutis a string (decoded), and there is no way to construct or manipulate raw byte sequences from within a script.Impact
This is a Stage 3 bootstrap gap: to write a Nodus compiler in Nodus itself, the compiler must be able to write compiled bytecode files. Without binary write and a byte array type, this is not possible.
Fix direction (v5)
write_file_bytes(path, bytes_list)builtin that opens with'wb'mode and writes a list of integers (0–255) as bytesread_file_bytes(path)that reads a file in binary mode and returns a list of integersBytesvalue type for more ergonomic binary handlingAs a stopgap,
std:subprocesscan write binary files by invoking system tools, but that's a workaround, not a solution.Affected versions
v4.0.0 (current when filed). Noted in Runtime Readiness Audit bootstrap table as MISSING.