Files
hermes-agent/tools/fuzzy_match_strategies.py
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Teknium d4cec15b47 refactor(tools): first-wave simplification of tools/ (file ops split, lazy_deps, code_exec, approval, browser, delegate, mcp, skills, terminal, voice, media)
Behavior-neutral structural pass over tools/*: god-file extractions into
sibling modules (file_operations_common/lint/search, file_tools_paths/
read_tracking/write, code_execution_env/rpc, tool_search_catalog/names/
validation, tts_command_provider, ...), duplicate helper unification,
if/elif -> dispatch tables, dead-code removal, docstring compaction.
Tool schemas (get_tool_definitions) verified byte-identical to base.
2026-09-02 14:43:45 -07:00

335 lines
14 KiB
Python

"""Matching strategies for :mod:`tools.fuzzy_match`.
Each strategy takes ``(content, pattern)`` and returns a list of
``(start, end)`` spans in the ORIGINAL content. ``STRATEGIES`` is the ordered
chain the orchestrator tries; ``SIMILARITY_STRATEGIES`` names the ones whose
matches are approximate and therefore unsafe under ``replace_all``.
"""
import re
from difflib import SequenceMatcher
from typing import Callable, Dict, List, Tuple
UNICODE_MAP = {
"\u201c": '"', "\u201d": '"', # smart double quotes
"\u2018": "'", "\u2019": "'", # smart single quotes
"\u2014": "--", "\u2013": "-", # em/en dashes
"\u2026": "...", "\u00a0": " ", # ellipsis and non-breaking space
"\u2212": "-", # typographic minus (math/scientific docs)
# Space-separator family (Zs) beyond NBSP: files with typographic spacing
# otherwise miss every precise strategy and fall through to the
# similarity fallback, which can pick the wrong region.
"\u2000": " ", "\u2001": " ", "\u2002": " ", "\u2003": " ",
"\u2004": " ", "\u2005": " ", "\u2006": " ", "\u2007": " ",
"\u2008": " ", "\u2009": " ", "\u200a": " ", "\u202f": " ",
"\u205f": " ", "\u3000": " ",
}
Span = Tuple[int, int]
def _unicode_normalize(text: str) -> str:
"""Map typographic Unicode variants to ASCII equivalents."""
for char, repl in UNICODE_MAP.items():
text = text.replace(char, repl)
return text
# ── Position helpers ─────────────────────────────────────────────────────
def _calculate_line_positions(content_lines: List[str], start_line: int,
end_line: int, content_length: int) -> Span:
"""Character span covering ``content_lines[start_line:end_line]`` (end exclusive)."""
start_pos = sum(len(line) + 1 for line in content_lines[:start_line])
end_pos = sum(len(line) + 1 for line in content_lines[:end_line]) - 1
return start_pos, min(content_length, end_pos)
def _match_transformed_lines(content: str, pattern: str,
transform: Callable[[str], str]) -> List[Span]:
"""Match ``pattern`` against ``content`` after applying ``transform`` per line."""
content_lines = content.split('\n')
norm_lines = [transform(line) for line in content_lines]
pattern_norm = '\n'.join(transform(line) for line in pattern.split('\n'))
n = pattern_norm.count('\n') + 1
matches = []
for i in range(len(norm_lines) - n + 1):
if '\n'.join(norm_lines[i:i + n]) == pattern_norm:
matches.append(_calculate_line_positions(content_lines, i, i + n, len(content)))
return matches
def _build_orig_to_norm_map(original: str) -> List[int]:
"""Map each original index to its index in ``_unicode_normalize(original)``.
UNICODE_MAP replacements can expand one char into several, so the map is
needed to translate normalised spans back. Length is ``len(original)+1``;
the last entry is a sentinel one past the final character.
"""
result: List[int] = []
norm_pos = 0
for char in original:
result.append(norm_pos)
repl = UNICODE_MAP.get(char)
norm_pos += len(repl) if repl is not None else 1
result.append(norm_pos)
return result
def _invert_norm_map(orig_to_norm: List[int]) -> Dict[int, int]:
"""norm_pos -> first original position mapping to it."""
inverted: Dict[int, int] = {}
for orig_pos, norm_pos in enumerate(orig_to_norm[:-1]):
if norm_pos not in inverted:
inverted[norm_pos] = orig_pos
return inverted
def _norm_end_to_orig(orig_to_norm: List[int], orig_start: int, norm_end: int) -> int:
"""Walk from ``orig_start`` until the mapped position reaches ``norm_end``."""
orig_len = len(orig_to_norm) - 1
orig_end = orig_start
while orig_end < orig_len and orig_to_norm[orig_end] < norm_end:
orig_end += 1
return orig_end
def _map_positions_norm_to_orig(orig_to_norm: List[int],
norm_matches: List[Span]) -> List[Span]:
"""Convert spans in the normalised string to original-string spans."""
norm_to_orig_start = _invert_norm_map(orig_to_norm)
results: List[Span] = []
for norm_start, norm_end in norm_matches:
if norm_start not in norm_to_orig_start:
continue
orig_start = norm_to_orig_start[norm_start]
results.append((orig_start, _norm_end_to_orig(orig_to_norm, orig_start, norm_end)))
return results
def _map_normalized_positions(original: str, normalized: str,
normalized_matches: List[Span]) -> List[Span]:
"""Best-effort span mapping for ``[ \\t]+`` -> ``' '`` whitespace collapsing."""
orig_to_norm = [] # orig_to_norm[i] = position in normalized
orig_idx = norm_idx = 0
while orig_idx < len(original) and norm_idx < len(normalized):
if original[orig_idx] == normalized[norm_idx]:
orig_to_norm.append(norm_idx)
orig_idx += 1
norm_idx += 1
elif original[orig_idx] in ' \t' and normalized[norm_idx] == ' ':
# Collapsed run: advance norm_idx only once the run is consumed.
orig_to_norm.append(norm_idx)
orig_idx += 1
if orig_idx < len(original) and original[orig_idx] not in ' \t':
norm_idx += 1
else:
# Extra whitespace in original, or a mismatch that normalization
# should never produce — either way, pin to the current norm_idx.
orig_to_norm.append(norm_idx)
orig_idx += 1
while orig_idx < len(original):
orig_to_norm.append(len(normalized))
orig_idx += 1
norm_to_orig_start = {}
norm_to_orig_end = {}
for orig_pos, norm_pos in enumerate(orig_to_norm):
if norm_pos not in norm_to_orig_start:
norm_to_orig_start[norm_pos] = orig_pos
norm_to_orig_end[norm_pos] = orig_pos
original_matches = []
for norm_start, norm_end in normalized_matches:
if norm_start in norm_to_orig_start:
orig_start = norm_to_orig_start[norm_start]
else:
orig_start = min(i for i, n in enumerate(orig_to_norm) if n >= norm_start)
if norm_end - 1 in norm_to_orig_end:
orig_end = norm_to_orig_end[norm_end - 1] + 1
else:
orig_end = orig_start + (norm_end - norm_start)
# Absorb trailing collapsed whitespace only when the normalized match
# itself ended in a space; otherwise the first whitespace after the
# match is a word boundary that must survive (#52491).
if norm_end < len(normalized) and normalized[norm_end - 1] == ' ':
while orig_end < len(original) and original[orig_end] in ' \t':
orig_end += 1
original_matches.append((orig_start, min(orig_end, len(original))))
return original_matches
# ── Strategies ───────────────────────────────────────────────────────────
def _strategy_exact(content: str, pattern: str) -> List[Span]:
"""Strategy 1: exact, non-overlapping occurrences (str.replace semantics)."""
matches = []
start = 0
while True:
pos = content.find(pattern, start)
if pos == -1:
break
matches.append((pos, pos + len(pattern)))
# Advance past the whole match: overlapping spans would corrupt the
# file under replace_all (reverse-order apply on stale offsets).
start = pos + len(pattern)
return matches
def _strategy_line_trimmed(content: str, pattern: str) -> List[Span]:
"""Strategy 2: strip each line before comparing."""
return _match_transformed_lines(content, pattern, str.strip)
def _strategy_whitespace_normalized(content: str, pattern: str) -> List[Span]:
"""Strategy 3: collapse runs of spaces/tabs to a single space."""
def normalize(s):
return re.sub(r'[ \t]+', ' ', s)
content_normalized = normalize(content)
matches_in_normalized = _strategy_exact(content_normalized, normalize(pattern))
if not matches_in_normalized:
return []
return _map_normalized_positions(content, content_normalized, matches_in_normalized)
def _strategy_indentation_flexible(content: str, pattern: str) -> List[Span]:
"""Strategy 4: ignore leading indentation entirely."""
return _match_transformed_lines(content, pattern, str.lstrip)
def _strategy_escape_normalized(content: str, pattern: str) -> List[Span]:
"""Strategy 5: treat literal ``\\n``/``\\t``/``\\r`` in the pattern as control chars."""
pattern_unescaped = pattern.replace('\\n', '\n').replace('\\t', '\t').replace('\\r', '\r')
if pattern_unescaped == pattern:
return []
return _strategy_exact(content, pattern_unescaped)
def _strategy_trimmed_boundary(content: str, pattern: str) -> List[Span]:
"""Strategy 6: strip whitespace on the first and last lines only."""
pattern_lines = pattern.split('\n')
pattern_lines[0] = pattern_lines[0].strip()
if len(pattern_lines) > 1:
pattern_lines[-1] = pattern_lines[-1].strip()
modified_pattern = '\n'.join(pattern_lines)
n = len(pattern_lines)
content_lines = content.split('\n')
matches = []
for i in range(len(content_lines) - n + 1):
check_lines = content_lines[i:i + n]
check_lines[0] = check_lines[0].strip()
if n > 1:
check_lines[-1] = check_lines[-1].strip()
if '\n'.join(check_lines) == modified_pattern:
matches.append(_calculate_line_positions(content_lines, i, i + n, len(content)))
return matches
def _strategy_unicode_normalized(content: str, pattern: str) -> List[Span]:
"""Strategy 7: exact/line-trimmed match after Unicode->ASCII normalisation of both sides."""
norm_pattern = _unicode_normalize(pattern)
norm_content = _unicode_normalize(content)
if norm_content == content and norm_pattern == pattern:
return []
norm_matches = _strategy_exact(norm_content, norm_pattern)
if not norm_matches:
norm_matches = _strategy_line_trimmed(norm_content, norm_pattern)
if not norm_matches:
return []
return _map_positions_norm_to_orig(_build_orig_to_norm_map(content), norm_matches)
def _strategy_block_anchor(content: str, pattern: str) -> List[Span]:
"""Strategy 8: anchor on first+last lines, similarity-score the middle."""
pattern_lines = _unicode_normalize(pattern).split('\n')
if len(pattern_lines) < 2:
return []
first_line = pattern_lines[0].strip()
last_line = pattern_lines[-1].strip()
n = len(pattern_lines)
# Match on normalized lines; compute offsets from the ORIGINAL lines so
# multi-char expansions (em-dash -> '--') don't shift positions.
norm_content_lines = _unicode_normalize(content).split('\n')
orig_content_lines = content.split('\n')
potential_matches = [
i for i in range(len(norm_content_lines) - n + 1)
if norm_content_lines[i].strip() == first_line
and norm_content_lines[i + n - 1].strip() == last_line
]
# Looser thresholds (0.10/0.30) matched unrelated blocks; these are the safe floor.
threshold = 0.50 if len(potential_matches) == 1 else 0.70
matches = []
for i in potential_matches:
if n <= 2:
similarity = 1.0
else:
content_middle = '\n'.join(norm_content_lines[i + 1:i + n - 1])
pattern_middle = '\n'.join(pattern_lines[1:-1])
similarity = SequenceMatcher(None, content_middle, pattern_middle).ratio()
if similarity >= threshold:
matches.append(_calculate_line_positions(orig_content_lines, i, i + n, len(content)))
return matches
def _strategy_context_aware(content: str, pattern: str) -> List[Span]:
"""Strategy 9 (last resort): anchored per-line similarity, every non-blank line >= 0.80.
The first/last-line anchor pre-filter keeps a miss from being an
O(file x pattern) scan; the all-lines requirement stops one coincidental
line match from replacing an unrelated block.
"""
pattern_lines = pattern.split('\n')
content_lines = content.split('\n')
n = len(pattern_lines)
if n > len(content_lines):
return []
first_pat = pattern_lines[0].strip()
last_pat = pattern_lines[-1].strip()
ANCHOR_THRESHOLD = 0.80
def _sim(a: str, b: str) -> float:
if a == b:
return 1.0
return SequenceMatcher(None, a, b).ratio()
matches = []
for i in range(len(content_lines) - n + 1):
block_lines = content_lines[i:i + n]
if _sim(first_pat, block_lines[0].strip()) < ANCHOR_THRESHOLD:
continue
if _sim(last_pat, block_lines[-1].strip()) < ANCHOR_THRESHOLD:
continue
all_match = True
for p_line, c_line in zip(pattern_lines, block_lines):
p_stripped = p_line.strip()
if p_stripped and _sim(p_stripped, c_line.strip()) < 0.80:
all_match = False
break
if all_match:
matches.append(_calculate_line_positions(content_lines, i, i + n, len(content)))
return matches
# Ordered chain: precise strategies first, similarity-based last.
STRATEGIES: List[Tuple[str, Callable[[str, str], List[Span]]]] = [
("exact", _strategy_exact),
("line_trimmed", _strategy_line_trimmed),
("whitespace_normalized", _strategy_whitespace_normalized),
("indentation_flexible", _strategy_indentation_flexible),
("escape_normalized", _strategy_escape_normalized),
("trimmed_boundary", _strategy_trimmed_boundary),
("unicode_normalized", _strategy_unicode_normalized),
("block_anchor", _strategy_block_anchor),
("context_aware", _strategy_context_aware),
]
# Matches from these only *approximately* resemble old_string — fine for one
# unique replacement, never safe under replace_all.
SIMILARITY_STRATEGIES = frozenset({"block_anchor", "context_aware"})