mirror of
https://github.com/NousResearch/hermes-agent.git
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e9f3f2b34a
When the patch tool matches via the escape_normalized strategy, old_string contains literal \t, \n, \r sequences that get unescaped to match real control characters in the file. However, new_string was written as-is, leaving literal backslash sequences in the output. Add _unescape_common_sequences() helper and apply it to new_string when the matching strategy is escape_normalized. This ensures LLM-generated tab/newline sequences become real bytes in the patched file. Fixes #33733
503 lines
21 KiB
Python
503 lines
21 KiB
Python
"""Tests for the fuzzy matching module."""
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from tools.fuzzy_match import fuzzy_find_and_replace
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class TestExactMatch:
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def test_single_replacement(self):
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content = "hello world"
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new, count, _, err = fuzzy_find_and_replace(content, "hello", "hi")
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assert err is None
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assert count == 1
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assert new == "hi world"
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def test_no_match(self):
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content = "hello world"
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new, count, _, err = fuzzy_find_and_replace(content, "xyz", "abc")
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assert count == 0
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assert err is not None
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assert new == content
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def test_empty_old_string(self):
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new, count, _, err = fuzzy_find_and_replace("abc", "", "x")
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assert count == 0
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assert err is not None
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def test_identical_strings(self):
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new, count, _, err = fuzzy_find_and_replace("abc", "abc", "abc")
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assert count == 0
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assert "identical" in err
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def test_multiline_exact(self):
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content = "line1\nline2\nline3"
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new, count, _, err = fuzzy_find_and_replace(content, "line1\nline2", "replaced")
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assert err is None
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assert count == 1
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assert new == "replaced\nline3"
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class TestWhitespaceDifference:
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def test_extra_spaces_match(self):
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content = "def foo( x, y ):"
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new, count, _, err = fuzzy_find_and_replace(content, "def foo( x, y ):", "def bar(x, y):")
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assert count == 1
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assert "bar" in new
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class TestIndentDifference:
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def test_different_indentation(self):
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content = " def foo():\n pass"
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new, count, _, err = fuzzy_find_and_replace(content, "def foo():\n pass", "def bar():\n return 1")
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assert count == 1
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assert "bar" in new
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class TestIndentationPreservation:
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"""When a non-exact strategy matches, ``new_string`` should be re-indented
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so it lands at the file's actual indent depth — not at whatever indent the
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LLM happened to send in the tool args. Without this fix the file gets a
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silently-broken indent level that may even still parse but is logically
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wrong."""
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def test_unindented_input_reindented_to_match_file(self):
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# File: 8-space-indented method body inside a class.
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content = (
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"class Calculator:\n"
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" def add(self, a, b):\n"
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" result = a + b\n"
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" return result\n"
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)
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# LLM sends zero-indent old/new — common bug from frontier models
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# that "remember" code instead of reading it.
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old = "result = a + b\nreturn result"
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new = "result = a + b\nresult *= 2\nreturn result"
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out, count, strategy, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and count == 1
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assert strategy != "exact" # must have gone through a fuzzy strategy
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# Every replaced line should be at 8-space indent.
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for marker in ("result = a + b", "result *= 2", "return result"):
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line = next(line for line in out.split("\n") if marker in line)
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indent = len(line) - len(line.lstrip())
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assert indent == 8, f"Expected 8-space indent for {marker!r}, got {indent}: {line!r}"
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# Resulting file must still be valid Python.
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import ast
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ast.parse(out)
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def test_dedent_at_start_anchors_to_file_base(self):
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# File: 2-space-indented function body. LLM sends zero-indent
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# old/new where new_string contains a dedent (the new structure
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# adds a top-level class wrapper). After re-indent, every line
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# of new_string should be anchored to the file's 2-space base.
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content = " return 1\n return 2\n"
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old = "return 1\nreturn 2" # zero-indent — forces line_trimmed
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new = "class X:\n return 99\n return 100"
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out, count, strategy, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and count == 1
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assert strategy != "exact"
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lines = out.split("\n")
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# 'class X:' anchored to file's 2-space base.
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assert lines[0] == " class X:", repr(lines[0])
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# Indented body lines lift to 4-space (file base + LLM's +2).
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assert lines[1] == " return 99", repr(lines[1])
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assert lines[2] == " return 100", repr(lines[2])
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def test_exact_match_no_reindent(self):
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# Exact strategy should be a pure passthrough — no shift logic
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# should touch the result.
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content = " def foo():\n return 1\n"
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old = " def foo():\n return 1"
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new = " def foo():\n return 2"
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out, count, strategy, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and strategy == "exact"
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assert out == " def foo():\n return 2\n"
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def test_llm_zero_indent_shifts_to_file_two_space(self):
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# LLM sent zero-indent old/new; file has 2-space indent. The
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# re-indent shifts the whole replacement so 'def x()' lands at
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# 2-space and the body keeps its relative +2 from new_string.
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content = " def x():\n return 1\n"
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old = "def x():\n return 1"
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new = "def x():\n return 99"
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out, count, _, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and count == 1
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lines = out.strip("\n").split("\n")
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assert lines[0] == " def x():"
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assert lines[1] == " return 99"
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def test_indent_already_matches_passthrough(self):
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# When old_string's base indent already equals file_region's base
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# indent, _reindent_replacement returns new_string unchanged.
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# Verify with whitespace_normalized strategy (collapsed spaces).
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content = " def x( ):\n return 1\n"
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old = " def x():\n return 1" # same base indent (2), different inner whitespace
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new = " def x():\n return 42"
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out, count, strategy, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and count == 1
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assert strategy != "exact" # non-exact strategy matched
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# Body retains its 4-space indent (passthrough — no shift).
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assert " return 42" in out
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def test_blank_lines_left_alone(self):
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# Blank lines in new_string should keep whatever whitespace they
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# had — we never strip or pad them.
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content = " a = 1\n b = 2\n"
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old = "a = 1\nb = 2"
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new = "a = 1\n\nb = 99"
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out, count, _, err = fuzzy_find_and_replace(content, old, new)
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assert err is None and count == 1
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# blank line is preserved (empty), indented lines anchored.
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lines = out.split("\n")
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assert lines[0] == " a = 1"
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assert lines[1] == ""
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assert lines[2] == " b = 99"
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class TestReplaceAll:
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def test_multiple_matches_without_flag_errors(self):
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content = "aaa bbb aaa"
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new, count, _, err = fuzzy_find_and_replace(content, "aaa", "ccc", replace_all=False)
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assert count == 0
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assert "Found 2 matches" in err
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def test_multiple_matches_with_flag(self):
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content = "aaa bbb aaa"
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new, count, _, err = fuzzy_find_and_replace(content, "aaa", "ccc", replace_all=True)
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assert err is None
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assert count == 2
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assert new == "ccc bbb ccc"
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class TestUnicodeNormalized:
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"""Tests for the unicode_normalized strategy (Bug 5)."""
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def test_em_dash_matched(self):
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"""Em-dash in content should match ASCII '--' in pattern."""
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content = "return value\u2014fallback"
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new, count, strategy, err = fuzzy_find_and_replace(
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content, "return value--fallback", "return value or fallback"
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)
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assert count == 1, f"Expected match via unicode_normalized, got err={err}"
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assert strategy == "unicode_normalized"
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assert "return value or fallback" in new
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def test_smart_quotes_matched(self):
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"""Smart double quotes in content should match straight quotes in pattern."""
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content = 'print(\u201chello\u201d)'
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new, count, strategy, err = fuzzy_find_and_replace(
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content, 'print("hello")', 'print("world")'
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)
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assert count == 1, f"Expected match via unicode_normalized, got err={err}"
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assert "world" in new
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def test_no_unicode_skips_strategy(self):
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"""When content and pattern have no Unicode variants, strategy is skipped."""
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content = "hello world"
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# Should match via exact, not unicode_normalized
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new, count, strategy, err = fuzzy_find_and_replace(content, "hello", "hi")
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assert count == 1
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assert strategy == "exact"
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class TestBlockAnchorThreshold:
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"""Tests for the raised block_anchor threshold (Bug 4)."""
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def test_high_similarity_matches(self):
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"""A block with >50% middle similarity should match."""
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content = "def foo():\n x = 1\n y = 2\n return x + y\n"
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pattern = "def foo():\n x = 1\n y = 9\n return x + y"
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new, count, strategy, err = fuzzy_find_and_replace(content, pattern, "def foo():\n return 0\n")
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# Should match via block_anchor or earlier strategy
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assert count == 1
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def test_completely_different_middle_does_not_match(self):
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"""A block where only first+last lines match but middle is completely different
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should NOT match under the raised 0.50 threshold."""
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content = (
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"class Foo:\n"
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" completely = 'unrelated'\n"
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" content = 'here'\n"
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" nothing = 'in common'\n"
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" pass\n"
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)
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# Pattern has same first/last lines but completely different middle
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pattern = (
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"class Foo:\n"
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" x = 1\n"
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" y = 2\n"
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" z = 3\n"
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" pass"
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)
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new, count, strategy, err = fuzzy_find_and_replace(content, pattern, "replaced")
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# With threshold=0.50, this near-zero-similarity middle should not match
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assert count == 0, (
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f"Block with unrelated middle should not match under threshold=0.50, "
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f"but matched via strategy={strategy}"
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)
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class TestStrategyNameSurfaced:
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"""Tests for the strategy name in the 4-tuple return (Bug 6)."""
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def test_exact_strategy_name(self):
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new, count, strategy, err = fuzzy_find_and_replace("hello", "hello", "world")
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assert strategy == "exact"
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assert count == 1
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def test_failed_match_returns_none_strategy(self):
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new, count, strategy, err = fuzzy_find_and_replace("hello", "xyz", "world")
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assert count == 0
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assert strategy is None
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class TestEscapeDriftGuard:
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"""Tests for the escape-drift guard that catches bash/JSON serialization
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artifacts where an apostrophe gets prefixed with a spurious backslash
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in tool-call transport.
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"""
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def test_drift_blocked_apostrophe(self):
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"""File has ', old_string and new_string both have \\' — classic
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tool-call drift. Guard must block with a helpful error instead of
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writing \\' literals into source code."""
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content = "x = \"hello there\"\n"
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# Simulate transport-corrupted old_string and new_string where an
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# apostrophe-like context got prefixed with a backslash. The content
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# itself has no apostrophe, but both strings do — matching via
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# whitespace/anchor strategies would otherwise succeed.
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old_string = "x = \"hello there\" # don\\'t edit\n"
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new_string = "x = \"hi there\" # don\\'t edit\n"
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# This particular pair won't match anything, so it exits via
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# no-match path. Build a case where a non-exact strategy DOES match.
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content = "line\n x = 1\nline"
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old_string = "line\n x = \\'a\\'\nline"
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new_string = "line\n x = \\'b\\'\nline"
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert count == 0
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assert err is not None and "Escape-drift" in err
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assert "backslash" in err.lower()
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assert new == content # file untouched
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def test_drift_blocked_double_quote(self):
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"""Same idea but with \\" drift instead of \\'."""
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content = 'line\n x = 1\nline'
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old_string = 'line\n x = \\"a\\"\nline'
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new_string = 'line\n x = \\"b\\"\nline'
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert count == 0
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assert err is not None and "Escape-drift" in err
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def test_drift_allowed_when_file_genuinely_has_backslash_escapes(self):
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"""If the file already contains \\' (e.g. inside an existing escaped
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string), the model is legitimately preserving it. Guard must NOT
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fire."""
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content = "line\n x = \\'a\\'\nline"
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old_string = "line\n x = \\'a\\'\nline"
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new_string = "line\n x = \\'b\\'\nline"
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert err is None
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assert count == 1
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assert "\\'b\\'" in new
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def test_drift_allowed_on_exact_match(self):
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"""Exact matches bypass the drift guard entirely — if the file
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really contains the exact bytes old_string specified, it's not
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drift."""
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content = "hello \\'world\\'"
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new, count, strategy, err = fuzzy_find_and_replace(
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content, "hello \\'world\\'", "hello \\'there\\'"
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)
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assert err is None
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assert count == 1
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assert strategy == "exact"
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def test_drift_allowed_when_adding_escaped_strings(self):
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"""Model is adding new content with \\' that wasn't in the original.
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old_string has no \\', so guard doesn't fire."""
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content = "line1\nline2\nline3"
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old_string = "line1\nline2\nline3"
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new_string = "line1\nprint(\\'added\\')\nline2\nline3"
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert err is None
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assert count == 1
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assert "\\'added\\'" in new
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def test_no_drift_check_when_new_string_lacks_suspect_chars(self):
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"""Fast-path: if new_string has no \\' or \\", guard must not
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fire even on fuzzy match."""
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content = "def foo():\n pass" # extra space ignored by line_trimmed
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old_string = "def foo():\n pass"
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new_string = "def bar():\n return 1"
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert err is None
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assert count == 1
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class TestFindClosestLines:
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def setup_method(self):
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from tools.fuzzy_match import find_closest_lines
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self.find_closest_lines = find_closest_lines
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def test_finds_similar_line(self):
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content = "def foo():\n pass\ndef bar():\n return 1\n"
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result = self.find_closest_lines("def baz():", content)
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assert "def foo" in result or "def bar" in result
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def test_returns_empty_for_no_match(self):
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content = "completely different content here"
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result = self.find_closest_lines("xyzzy_no_match_possible_!!!", content)
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assert result == ""
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def test_returns_empty_for_empty_inputs(self):
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assert self.find_closest_lines("", "some content") == ""
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assert self.find_closest_lines("old string", "") == ""
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def test_includes_context_lines(self):
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content = "line1\nline2\ndef target():\n pass\nline5\n"
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result = self.find_closest_lines("def target():", content)
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assert "target" in result
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def test_includes_line_numbers(self):
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content = "line1\nline2\ndef foo():\n pass\n"
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result = self.find_closest_lines("def foo():", content)
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# Should include line numbers in format "N| content"
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assert "|" in result
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class TestFormatNoMatchHint:
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"""Gating tests for format_no_match_hint — the shared helper that decides
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whether a 'Did you mean?' snippet should be appended to an error.
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"""
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def setup_method(self):
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from tools.fuzzy_match import format_no_match_hint
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self.fmt = format_no_match_hint
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def test_fires_on_could_not_find_with_match(self):
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"""Classic no-match: similar content exists → hint fires."""
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content = "def foo():\n pass\ndef bar():\n pass\n"
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result = self.fmt(
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"Could not find a match for old_string in the file",
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0, "def baz():", content,
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)
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assert "Did you mean" in result
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assert "foo" in result or "bar" in result
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def test_silent_on_ambiguous_match_error(self):
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"""'Found N matches' is not a missing-match failure — no hint."""
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content = "aaa bbb aaa\n"
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result = self.fmt(
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"Found 2 matches for old_string. Provide more context to make it unique, or use replace_all=True.",
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0, "aaa", content,
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)
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assert result == ""
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def test_silent_on_escape_drift_error(self):
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"""Escape-drift errors are intentional blocks — hint would mislead."""
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content = "x = 1\n"
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result = self.fmt(
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"Escape-drift detected: old_string and new_string contain the literal sequence '\\\\''...",
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0, "x = \\'1\\'", content,
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)
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assert result == ""
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def test_silent_on_identical_strings(self):
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"""old_string == new_string — hint irrelevant."""
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result = self.fmt(
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"old_string and new_string are identical",
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0, "foo", "foo bar\n",
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)
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assert result == ""
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def test_silent_when_match_count_nonzero(self):
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"""If match succeeded, we shouldn't be in the error path — defense in depth."""
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result = self.fmt(
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"Could not find a match for old_string in the file",
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1, "foo", "foo bar\n",
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)
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assert result == ""
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def test_silent_on_none_error(self):
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"""No error at all — no hint."""
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result = self.fmt(None, 0, "foo", "bar\n")
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assert result == ""
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def test_silent_when_no_similar_content(self):
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"""Even for a valid no-match error, skip hint when nothing similar exists."""
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result = self.fmt(
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"Could not find a match for old_string in the file",
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0, "totally_unique_xyzzy_qux", "abc\nxyz\n",
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)
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assert result == ""
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class TestEscapeNormalizedNewString:
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"""Regression tests for unescaping common sequences in new_string
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when the match succeeded via the escape_normalized strategy.
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Issue #33733: LLMs overwhelmingly represent tabs as the two-character
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sequence \\t (backslash + t) in JSON tool-call arguments. When the file
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contains real tab bytes (0x09), the escape_normalized strategy matches
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old_string by unescaping it — but new_string was written as-is, leaving
|
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literal \\t characters in the file.
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"""
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def test_tab_in_new_string_unescaped(self):
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"""File has real tab, model sends literal \\t in new_string."""
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content = "def hello():\n\tprint(\"before\")\n"
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old_string = "def hello():\n\\tprint(\"before\")\n"
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new_string = "def hello():\n\\tprint(\"after\")\n"
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new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
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assert err is None, f"Unexpected error: {err}"
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|
assert count == 1
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|
assert strategy == "escape_normalized"
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|
# Must contain a real tab, not literal \t
|
|
assert "\tprint(\"after\")" in new
|
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assert "\\t" not in new
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|
|
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def test_newline_in_new_string_unescaped(self):
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"""File has real newlines, model sends literal \\n in new_string."""
|
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content = "line1\nline2\nline3\n"
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|
old_string = "line1\\nline2\\n"
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|
new_string = "line1\\nreplaced\\n"
|
|
new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
|
|
assert err is None, f"Unexpected error: {err}"
|
|
assert count == 1
|
|
assert strategy == "escape_normalized"
|
|
assert "replaced" in new
|
|
assert "\\n" not in new
|
|
|
|
def test_carriage_return_in_new_string_unescaped(self):
|
|
"""File has real CR, model sends literal \\r in new_string."""
|
|
content = "line1\r\nline2\r\n"
|
|
old_string = "line1\\r\\nline2\\r\\n"
|
|
new_string = "replaced\\r\\n"
|
|
new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
|
|
assert err is None, f"Unexpected error: {err}"
|
|
assert count == 1
|
|
assert strategy == "escape_normalized"
|
|
assert "replaced\r" in new
|
|
|
|
def test_mixed_escape_sequences_in_new_string(self):
|
|
"""Model sends \\t and \\n together in new_string."""
|
|
content = "def foo():\n\tpass\n"
|
|
old_string = "def foo():\\n\\tpass\\n"
|
|
new_string = "def bar():\\n\\treturn 1\\n"
|
|
new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
|
|
assert err is None, f"Unexpected error: {err}"
|
|
assert count == 1
|
|
assert strategy == "escape_normalized"
|
|
assert "\treturn 1" in new
|
|
assert "\\t" not in new
|
|
assert "\\n" not in new
|
|
|
|
def test_exact_match_preserves_literal_escapes(self):
|
|
"""When matching via exact strategy, literal \\t in new_string should
|
|
NOT be unescaped — the file genuinely contains backslash-t characters."""
|
|
content = "path = \"C:\\\\Users\\\"\n"
|
|
old_string = "path = \"C:\\\\Users\\\"\n"
|
|
new_string = "path = \"D:\\\\data\\\"\n"
|
|
new, count, strategy, err = fuzzy_find_and_replace(content, old_string, new_string)
|
|
assert err is None
|
|
assert strategy == "exact"
|
|
# Literal backslashes should be preserved
|
|
assert "\\\\" in new
|