Files
ragflow/deepdoc/parser/txt_parser.py
S 776b9371f7 fix(nlp): drop dead re.I from delimiter finditer calls (#17386)
Closes #17384.

## Summary

Drops a dead `re.I` flag from two outlier delimiter-parsing sites and
adds regression tests so the inconsistency can't creep back.

## What's wrong

Two of the six delimiter-parsing implementations pass `re.I` to
`re.finditer`:

- `rag/nlp/__init__.py::get_delimiters` (line 1633)
- `deepdoc/parser/txt_parser.py::parser_txt` (line 51)

The other four implementations correctly omit `re.I`:

- `rag/nlp/__init__.py::naive_merge` custom-delimiter path (line 1195)
- `rag/nlp/__init__.py::naive_merge_with_images` custom-delimiter path
(line 1269)
- `rag/nlp/__init__.py::_build_cks` (line 1389)
- `rag/flow/chunker/token_chunker.py` (line 73)

## Why this matters (and why it doesn't break anything)

The flag is **dead code** today. Verified empirically with a Python
REPL:

```python
>>> import re
>>> for m in re.finditer(r"`([^`]+)`", "`end`", re.I):
...     print(repr(m.group(1)))
'end'                           # plain string, no flag attached
>>> re.split("(a)", "Class A is a Sample")
['Cl', 'a', '', 's', ' A i', 's', ' a Sample']
# Case-sensitive: only lowercase 'a' splits. Uppercase 'A' is preserved.
```

`re.I` does not propagate from `re.finditer` to `m.group(1)` or to
downstream `re.split` / `re.match` calls (which all omit `re.I`). So the
actual splitting behavior has always been case-sensitive — removing the
flag is a **defensive cleanup**, not a behavioral fix.

So why bother?

1. **Consistency** — the two sites were the only outliers in a six-way
implementation cluster. The three sibling sites in `rag/nlp/__init__.py`
already omit `re.I`, which strongly suggests the flag was accidental.
2. **Future-proofing** — a refactor could easily propagate the flag to a
downstream `re.split` call where it *would* change behavior. The tests
added here pin the case-sensitive semantics so that regression fails
loudly.
3. **Reader clarity** — the flag is misleading. Anyone reading
`re.finditer(..., re.I)` reasonably assumes case-insensitive matching,
then has to trace all downstream calls to discover it's a no-op.

## Changes

- `rag/nlp/__init__.py` — drop `re.I` from `get_delimiters` (line 1633).
- `deepdoc/parser/txt_parser.py` — drop `re.I` from `parser_txt` (line
51).
- `test/unit_test/rag/test_delimiter_case_sensitive.py` — new test file
with:
- 4 behavioral tests on `get_delimiters` (pattern output + `re.split`
round-trip).
- 3 end-to-end tests through `naive_merge` (bare-char +
backtick-wrapped, both cases).
- 2 parametrized static checks that `re.I` / `re.IGNORECASE` is not
present at either of the two `re.finditer` sites.

## Testing

```
$ pytest test/unit_test/rag/test_delimiter_case_sensitive.py -v
============================= 9 passed in 0.19s ==============================
```

All tests pass on the patched code. Before the patch, the 2 static
checks fail with a clear assertion message (the 7 behavioral tests pass
either way, confirming `re.I` was dead code).

## Related

- #17384 — the issue this PR closes. Note the issue's reproduction code
(`re.split(..., flags=re.I)`) doesn't actually match what the production
code does — the production `re.split` calls all omit `re.I`, which is
why current behavior is already case-sensitive. The fix here is still
valuable as a defensive cleanup + test coverage, but it's not a
behavioral fix per se.
- #17383 — broader parser consolidation (six implementations → one). The
fix here is independent and small enough to land first.
- #17385 — sibling UX PR (tooltip + live preview). Files are disjoint
(`web/src/**` vs `rag/nlp/**` + `deepdoc/parser/**`), so no interaction.

---------

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Co-authored-by: kiloconnect[bot] <240665456+kiloconnect[bot]@users.noreply.github.com>
2026-07-31 22:59:12 +08:00

68 lines
2.3 KiB
Python

#
# Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import re
from deepdoc.parser.utils import get_text
from common.token_utils import num_tokens_from_string
class RAGFlowTxtParser:
def __call__(self, fnm, binary=None, chunk_token_num=128, delimiter="\n!?;。;!?"):
txt = get_text(fnm, binary)
return self.parser_txt(txt, chunk_token_num, delimiter)
@classmethod
def parser_txt(cls, txt, chunk_token_num=128, delimiter="\n!?;。;!?"):
if not isinstance(txt, str):
raise TypeError("txt type should be str!")
cks = [""]
tk_nums = [0]
delimiter = delimiter.encode("utf-8").decode("unicode_escape").encode("latin1").decode("utf-8")
def add_chunk(t):
nonlocal cks, tk_nums, delimiter
tnum = num_tokens_from_string(t)
if tk_nums[-1] > chunk_token_num:
cks.append(t)
tk_nums.append(tnum)
else:
if cks[-1]:
cks[-1] += "\n" + t
else:
cks[-1] += t
tk_nums[-1] += tnum
dels = []
s = 0
for m in re.finditer(r"`([^`]+)`", delimiter):
f, t = m.span()
dels.append(m.group(1))
dels.extend(list(delimiter[s:f]))
s = t
if s < len(delimiter):
dels.extend(list(delimiter[s:]))
dels = [re.escape(d) for d in dels if d]
dels = [d for d in dels if d]
dels = "|".join(dels)
secs = re.split(r"(%s)" % dels, txt)
for sec in secs:
if re.match(f"^{dels}$", sec):
continue
add_chunk(sec)
return [[c, ""] for c in cks]