headroom/tests/test_transforms_content_detection.py
Raúl 7784bb1846
fix(transforms): stop folding datetime-prefixed user messages as search results (#3221)
## Description

Interactive `headroom wrap copilot` sessions intermittently lose the
user's message: the model answers "How can I help you today?" to a real
task prompt. Root cause: Copilot CLI prepends
`<current_datetime>…</current_datetime>` to every interactive user turn;
the ISO-8601 timestamp matches the grep `file:line:` detector, so a
datetime + one-line prompt (1 match / 2 non-empty lines = 50% ≥ 30%)
classifies as `SEARCH_RESULTS`, and `SearchCompressor` — which keeps
only detector-matching lines — deletes the prompt before upstream. On
the OpenAI chat streaming path there is no retrieval tool, so the loss
is unrecoverable.

Fix: `_try_detect_search` now (a) requires the pre-colon segment to look
like a file path (no `<`, `>`, `=`), and (b) requires at least two
matching lines, so one coincidental `word:digits:` line can no longer
classify a whole payload. A genuine one-line grep result loses nothing:
all its lines match, so the compressor would have kept it verbatim
anyway.

Closes #3220

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)

## Changes Made

- `headroom/transforms/content_detector.py`: new
`_is_search_result_line` helper (path-like prefix gate);
`_try_detect_search` gains a two-matching-line absolute floor.
- `tests/test_transforms_content_detection.py`: regression tests —
datetime-prefixed one-liner not search; two-line floor; tag-like /
`key=value` prefixes rejected; genuine grep output still detected.
- `tests/test_transforms_content_router.py`: router-level regression —
the incident payload never routes to SEARCH and the prose survives
`ContentRouter().compress()`.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [x] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [x] Manual testing performed

### Test Output

```text
$ .venv/bin/python -m pytest tests/test_transforms_content_detection.py tests/test_transforms_content_router.py tests/test_mixed_content_sections.py tests/test_text_compressors.py tests/test_transforms_tabular.py -q
135 passed in 21.06s

$ .venv/bin/ruff check headroom/transforms/content_detector.py tests/test_transforms_content_detection.py tests/test_transforms_content_router.py
All checks passed!

$ .venv/bin/mypy headroom/transforms/content_detector.py
Success: no issues found in 1 source file
```

## Real Behavior Proof

- Environment: macOS 26.5 arm64, Python 3.13, editable source build
0.37.0-dev; upstream `api.githubcopilot.com`, cheapest subscription
model `kimi-k2.7-code`.
- Exact command / steps: standalone copilot-routed proxy
(`OPENAI_TARGET_API_URL=https://api.githubcopilot.com headroom proxy
--port 8899`) + `.overlay/e2e-copilot-content-probe.sh --port 8899
--model kimi-k2.7-code`, which sends the real interactive wire shape
(`<current_datetime>…` + one-line sentinel prompt, streaming) and a
multi-line control.
- Observed result: BEFORE the fix, probe 1 FAIL — model replied "Hello!
I see the current datetime is … How can I assist you today?" with proxy
log `transforms=router:search:0.50` (prompt deleted). AFTER the fix,
both probes PASS — the sentinel echoes verbatim, proving the user
message reached upstream intact.
- Not tested: other harnesses' interactive wrappers (claude/droid/auggie
send different shapes; the detector fix is generic); the mixed-content
section splitter has its own grep pattern (out of scope — its 1-line
"search" sections are kept verbatim, no data loss).

## Runtime Rollout Safety

- Rollout-managed feature(s): none.
- Minimum rollout channel: N/A (no flag).
- Stable/default behavior changed: content with exactly one
`path:line:`-shaped line no longer classifies as search results (stays
uncompressed instead — safe direction; compression only ever engages on
≥2 matching lines now).
- Kill switch / disable path: N/A.
- Unsafe override required: no.
- Qualification impact: none.
- Rollback path: revert; prior behavior restores (with the bug).

## Review Readiness

- [x] I have performed a self-review
- [x] This PR is ready for human review

## Checklist

- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] I did **not** edit `CHANGELOG.md` — it is generated by
release-please from my Conventional Commit PR title (a CI guard enforces
this)

## Screenshots (if applicable)

N/A — proxy transform change; no UI.

## Additional Notes

Detection-precision tradeoff is documented in code comments: single-line
genuine grep output is no longer folded (no data loss either way — the
compressor keeps all-matching content verbatim). A residual edge (prose
with ≥2 coincidental `x:1:` lines in ≤6 lines) is accepted and
documented in the issue.
2026-08-23 11:53:17 -07:00

311 lines
12 KiB
Python

from __future__ import annotations
import json
from headroom.transforms.content_detector import (
ContentType,
_try_detect_code,
_try_detect_diff,
_try_detect_html,
_try_detect_json,
_try_detect_log,
_try_detect_search,
detect_content_type,
is_json_array_of_dicts,
normalize_concatenated_json,
)
from headroom.transforms.error_detection import (
ERROR_INDICATOR_KEYWORDS,
ERROR_KEYWORDS,
ERROR_PATTERN,
IMPORTANCE_KEYWORDS,
IMPORTANCE_PATTERN,
PRIORITY_PATTERNS_DIFF,
PRIORITY_PATTERNS_SEARCH,
PRIORITY_PATTERNS_TEXT,
SECURITY_KEYWORDS,
SECURITY_PATTERN,
WARNING_PATTERN,
content_has_error_indicators,
)
def test_detect_content_type_handles_empty_and_plain_text() -> None:
empty = detect_content_type(" ")
assert empty.content_type is ContentType.PLAIN_TEXT
assert empty.confidence == 0.0
plain = detect_content_type("just a normal paragraph with no strong patterns")
assert plain.content_type is ContentType.PLAIN_TEXT
assert plain.confidence == 0.5
def test_json_detection_distinguishes_dict_arrays_and_other_lists() -> None:
dict_result = _try_detect_json('[{"id": 1}, {"id": 2}]')
assert dict_result is not None
assert dict_result.content_type is ContentType.JSON_ARRAY
assert dict_result.confidence == 1.0
assert dict_result.metadata == {"item_count": 2, "is_dict_array": True}
scalar_result = _try_detect_json("[1, 2, 3]")
assert scalar_result is not None
assert scalar_result.confidence == 0.8
assert scalar_result.metadata == {"item_count": 3, "is_dict_array": False}
empty_result = _try_detect_json("[]")
assert empty_result is not None
assert empty_result.metadata == {"item_count": 0, "is_dict_array": False}
# JSON OBJECTS are recognized too (config/data files are ``{…}``, not arrays).
object_result = _try_detect_json('{"id": 1}')
assert object_result is not None
assert object_result.content_type is ContentType.JSON_ARRAY
assert object_result.metadata == {"is_dict_array": False, "is_object": True}
assert _try_detect_json("[not valid json") is None
assert is_json_array_of_dicts('[{"id": 1}]') is True
assert is_json_array_of_dicts('["value"]') is False
def test_space_separated_json_objects_detected_as_array() -> None:
# Typical web_search output: back-to-back JSON objects, no array brackets.
content = " ".join(
json.dumps({"title": f"Result {i}", "url": f"http://example.com/{i}"}) for i in range(3)
)
result = _try_detect_json(content)
assert result is not None
assert result.content_type is ContentType.JSON_ARRAY
assert result.confidence == 1.0
assert result.metadata == {"item_count": 3, "is_dict_array": True, "concatenated": True}
# Reaches the same verdict through the top-level detector (not PLAIN_TEXT).
assert detect_content_type(content).content_type is ContentType.JSON_ARRAY
assert is_json_array_of_dicts(content) is True
# Newline separation is just as common and must also be recognized.
newline_sep = "\n".join(json.dumps({"id": i, "snippet": "x"}) for i in range(2))
assert _try_detect_json(newline_sep).content_type is ContentType.JSON_ARRAY
def test_json_detection_is_liberal_but_bulk_gated() -> None:
# Liberal (parse-based): a lone JSON object IS structured data worth routing —
# config/data files are ``{...}`` (chosen over the earlier conservative stance
# when this PR merged with the concatenated-JSON detector, #1742).
assert _try_detect_json('{"id": 1}').content_type is ContentType.JSON_ARRAY
# But a JSON fragment that is only a minority of the content (prose or a loose
# scalar around it) is NOT claimed — the decoded value must be the bulk.
assert _try_detect_json('{"id": 1} then some prose {"id": 2}') is None
assert _try_detect_json('{"id": 1} "loose string"') is None
def test_normalize_concatenated_json_roundtrips_to_array() -> None:
content = '{"a": 1} {"b": 2}'
normalized = normalize_concatenated_json(content)
assert normalized is not None
assert json.loads(normalized) == [{"a": 1}, {"b": 2}]
# Already-valid arrays and single objects are left for the caller as-is.
assert normalize_concatenated_json('[{"a": 1}]') is None
assert normalize_concatenated_json('{"a": 1}') is None
def test_diff_detection_tracks_headers_and_changes() -> None:
diff = "\n".join(
[
"diff --git a/app.py b/app.py",
"--- a/app.py",
"@@ -1,2 +1,2 @@",
"-old line",
"+new line",
]
)
result = _try_detect_diff(diff)
assert result is not None
assert result.content_type is ContentType.GIT_DIFF
assert result.metadata["header_matches"] == 3
assert result.metadata["change_lines"] == 2
assert result.confidence == 1.0
assert detect_content_type(diff).content_type is ContentType.GIT_DIFF
assert _try_detect_diff("+not enough by itself") is None
def test_html_detection_requires_real_structure() -> None:
html = """
<!DOCTYPE html>
<html>
<head><meta charset="utf-8"></head>
<body><main><section><div>Hello</div><nav>Links</nav></section></main></body>
</html>
"""
result = _try_detect_html(html)
assert result is not None
assert result.content_type is ContentType.HTML
assert result.metadata["has_doctype"] is True
assert result.metadata["has_html_tag"] is True
assert result.metadata["structural_tags"] >= 3
assert detect_content_type(html).content_type is ContentType.HTML
assert _try_detect_html("<div>only one tag</div>") is None
assert _try_detect_html("<html><title>too sparse</title></html>") is None
def test_search_detection_uses_match_ratio() -> None:
search_output = "\n".join(
[
"src/app.py:10:def main():",
"src/app.py:20:print('hello')",
"README.md:5:usage docs",
"plain text footer",
]
)
result = _try_detect_search(search_output)
assert result is not None
assert result.content_type is ContentType.SEARCH_RESULTS
assert result.metadata == {"matching_lines": 3, "total_lines": 4}
assert result.confidence == 0.85
assert detect_content_type(search_output).content_type is ContentType.SEARCH_RESULTS
assert _try_detect_search("one:1:match\nplain\nplain\nplain") is None
assert _try_detect_search("\n\n") is None
def test_search_detection_rejects_datetime_prefixed_user_message() -> None:
"""Regression: wrap-copilot ate one-line interactive prompts (2026-08-23).
Copilot CLI prepends ``<current_datetime>…</current_datetime>`` to every
interactive user turn. The ISO-8601 ``T09:57:59`` matched the grep
``file:line:`` pattern, so a datetime + one-line prompt classified as
SEARCH_RESULTS (1 match / 2 lines = 50% ≥ 30%) and the SearchCompressor
deleted the prompt line — the model received only the timestamp.
"""
incident = (
"<current_datetime>2026-08-23T09:57:59.792+02:00</current_datetime>\n"
"\n"
"Please update the PR desc and check .overlay/ for hints."
)
assert _try_detect_search(incident) is None
assert detect_content_type(incident).content_type is not ContentType.SEARCH_RESULTS
def test_search_detection_requires_two_matching_lines() -> None:
"""A single coincidental ``word:digits:`` line must not classify prose."""
assert _try_detect_search("src/foo.py:12:def foo():") is None
assert (
_try_detect_search(
"Meeting at 09:30:00 tomorrow.\nBring the reports.\nDo not forget coffee."
)
is None
)
# Two genuine grep lines still classify.
two = "src/foo.py:12:def foo():\nsrc/bar.py:34: foo()"
result = _try_detect_search(two)
assert result is not None
assert result.content_type is ContentType.SEARCH_RESULTS
def test_search_detection_rejects_tag_like_and_key_value_prefixes() -> None:
"""Markup / key=value lines are not file paths even with ``:\\d+:`` inside."""
assert (
_try_detect_search('<log time="10:00:00">started</log>\n<log time="10:00:01">stopped</log>')
is None
)
assert _try_detect_search("timeout=30:12:retried\ntimeout=31:12:retried") is None
def test_log_detection_prefers_build_output_patterns() -> None:
log_output = "\n".join(
[
"2025-01-01 Starting run",
"ERROR failed to compile",
"WARNING retrying build",
"PASSED unit test",
"Traceback (most recent call last)",
"plain footer",
]
)
result = _try_detect_log(log_output)
assert result is not None
assert result.content_type is ContentType.BUILD_OUTPUT
assert result.metadata == {"pattern_matches": 5, "error_matches": 2, "total_lines": 6}
assert result.confidence == 0.8166666666666667
assert detect_content_type(log_output).content_type is ContentType.BUILD_OUTPUT
assert _try_detect_log("plain\ntext\nonly") is None
assert _try_detect_log("\n\n") is None
assert _try_detect_log("\n".join(["ERROR one", *["plain"] * 15])) is None
def test_code_detection_identifies_language_and_thresholds() -> None:
python_code = "\n".join(
[
"import os",
"from pathlib import Path",
"",
"@cached",
"class App:",
" pass",
"def main():",
' """Run."""',
]
)
result = _try_detect_code(python_code)
assert result is not None
assert result.content_type is ContentType.SOURCE_CODE
assert result.metadata == {"language": "python", "pattern_matches": 6}
assert result.confidence == 0.8628571428571429
assert detect_content_type(python_code).content_type is ContentType.SOURCE_CODE
assert _try_detect_code("function maybe() {}\nplain text") is None
assert _try_detect_code("import os\ndef main():") is None
assert _try_detect_code("\n\n") is None
def test_detect_content_type_respects_priority_order() -> None:
diff_like_search = "\n".join(
[
"diff --git a/src/app.py b/src/app.py",
"@@ -1,1 +1,1 @@",
"+src/app.py:10:def still_diff_first()",
]
)
assert detect_content_type(diff_like_search).content_type is ContentType.GIT_DIFF
def test_error_detection_keywords_patterns_and_indicator_helper() -> None:
assert {"error", "failed", "critical"} <= ERROR_KEYWORDS
# fixed_in_3e1: ERROR_KEYWORDS canonically had timeout/abort/denied/rejected
# but the regex omitted them; the Rust port + Python shim now align.
assert {"timeout", "abort", "denied", "rejected"} <= ERROR_KEYWORDS
assert {"warning", "todo", "fix"} <= IMPORTANCE_KEYWORDS
# fixed_in_3e1: 'token' was dropped from SECURITY_KEYWORDS because it
# false-positived on every LLM-token reference (input_tokens, etc.) in
# an LLM-proxy product. 'auth' carries the real security signal.
assert {"security", "password", "auth", "secret"} <= SECURITY_KEYWORDS
assert "token" not in SECURITY_KEYWORDS
assert ERROR_INDICATOR_KEYWORDS[0] == "error"
assert ERROR_PATTERN.search("Fatal error occurred")
# fixed_in_3e1: timeout now matched by ERROR_PATTERN regex.
assert ERROR_PATTERN.search("Connection timeout occurred")
assert WARNING_PATTERN.search("warning: be careful")
assert IMPORTANCE_PATTERN.search("TODO fix this hack")
# fixed_in_3e1: pre-3e1 this matched via 'token'; now matches via 'auth'.
assert SECURITY_PATTERN.search("rotate the auth header")
# fixed_in_3e1: lone 'token' references no longer trigger security routing.
assert SECURITY_PATTERN.search("input_tokens=512 output_tokens=128") is None
assert PRIORITY_PATTERNS_SEARCH[:3] == [ERROR_PATTERN, WARNING_PATTERN, IMPORTANCE_PATTERN]
assert PRIORITY_PATTERNS_DIFF == [ERROR_PATTERN, IMPORTANCE_PATTERN, SECURITY_PATTERN]
assert PRIORITY_PATTERNS_TEXT[0] is ERROR_PATTERN
assert PRIORITY_PATTERNS_TEXT[1] is IMPORTANCE_PATTERN
# The Rust-supplied markdown_prefixes order is `# `, `## `, `### `, `#### `,
# `**`, `> ` (see KeywordRegistry::default_set). Index 2 is `# ` not `## `,
# so anchor each assertion on the prefix it actually owns.
assert PRIORITY_PATTERNS_TEXT[2].match("# Top-level heading")
assert PRIORITY_PATTERNS_TEXT[3].match("## Subheading")
assert PRIORITY_PATTERNS_TEXT[6].match("**Bold")
assert PRIORITY_PATTERNS_TEXT[7].match("> quote")
assert content_has_error_indicators("TRACEBACK: Fatal crash in worker") is True
assert content_has_error_indicators("Everything completed successfully") is False