* fix(middlewares): include file line count in read-before-write block message and clarify read_file range error
* fix(middlewares): address review feedback on line count pluralization and readability
* fix(middlewares): address round-2 review feedback for PR #6020
Stamping bug (_attach_read_mark, ggnnggez item 1):
Originally planned as a standalone issue; folded here since it is the exact mechanism behind the #6019 gate bypass. _attach_read_mark now returns early when message.content is in READ_FILE_NO_CONTENT_RESULTS - {READ_FILE_EMPTY}. In-band errors (invalid range, start_line exceeds file length, etc.) are returned with status='success' by LangChain so the existing message.status == 'error' guard did not catch them.
HTTP code collision [P3] (willem-bd):
Pre-stamp TOOL_META_KEY on the blocked ToolMessage before normalize_tool_result so files with 401, 403, 404, or 500 lines are not misclassified as auth/server errors by _classify_error_text. normalize_tool_message returns early when an existing TOOL_META_KEY entry is found.
Line-count parity (ggnnggez, inline L317):
Replace splitlines() with count_file_lines() in read_file_contract.py using count('\n'), matching LocalSandbox text-mode iteration and the _truncate_read_file_output formula. splitlines() over-counts for files with \f or \u2028 separators (e.g. pdftotext output).
Read hint (ggnnggez, inline _BLOCK_MESSAGE):
For empty files the ranged-read suggestion is omitted. For non-empty files the hint gives a concrete start_line=max(1, N-29), end_line=N.
Constant rename (ggnnggez, read_file_contract.py):
READ_FILE_INVALID_RANGE is the new canonical name; READ_FILE_EMPTY_RANGE kept as a backward-compat alias. _LEGACY_READ_FILE_EMPTY_RANGE removed (unreachable after the #6019 contract update).
Tests:
- TestBlockMessageLineCount parametrized with \f and \u2028 parity cases
- TestStampingGateBugFix: 4 no-content variants, gate-closed integration probe, empty-file-still-stamps assertion
- test_gate_block_on_numeric_line_count_is_recoverable: 401/403/404/500
- test_contract_constants_membership replaced with test_contract_constants_parity_with_localsandbox
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NOT INCLUDED: ggnnggez item 2 (file length in read_file range error strings). READ_FILE_NO_CONTENT_RESULTS uses exact string membership and is also consumed by build_skill_usage for skill-read detection; making those strings dynamic requires a dedicated contract refactor. Deferred to a follow-up PR.
Note: test_web_fetch_relative_links failures in the full suite are pre-existing on upstream/main and unrelated to this change.
* test: clarify blank ranged reads in the write gate
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
read_file decodes with UTF-8. Binary uploads (.xlsx, images, ...) raise
UnicodeDecodeError in the sandbox layer. UnicodeDecodeError is a ValueError
subclass, not an OSError, so it bypassed the typed handlers and fell through
to the generic except, surfacing a vague "Unexpected error reading file"
message. The model could not tell the file was binary, so it retried
read_file instead of switching to bash + pandas/openpyxl, burning LLM
round-trips and bloating context with repeated failures.
Add a dedicated UnicodeDecodeError handler that tells the model the file is
binary and to use bash with a suitable library (or view_image for images).
