Add checking if both strings are the same in `SequenceMatcher.find_longest_match`

Feature or enhancement

Proposal:

Add checking if sequences a[alo:ahi] and b[blo:bhi] are the same on the beginning of the method find_longest_match in SequenceMatcher. For identical sequences there is no reason to run whole logic when simple check can be done. It appears to fix issue when comparing two slightly different strings ends up with waiting forever for the result. This solves problem reported here https://github.com/pytest-dev/pytest/issues/8998

Proposed fix:

if a[alo:ahi] == b[blo:bhi]:
    return Match(alo, blo, len(a[alo:ahi]))

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-132167

從 SequenceMatcher.find_longest_match 開始，檢查它如何處理要求的序列比較。查看連結的 pytest 報告中關於卡住行為的內容，然後為相同字串和略有不同的字串新增針對性的覆蓋；完成標準是最佳化能夠正常運作，同時不改變傳回的 match。