gh-149028: Revert gh-92936 changes

[serhiy-storchaka]

Revert "gh-92936: allow double quote in cookie values (#113663)"
This reverts commit d7dbde8.

Revert "gh-92936: update http.cookies docs post GH-113663 (#137566)"
This reverts commit d86c225.

• Issue: SimpleCookie regex can make parsing extremely slow for adversarial payloads #149028

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32482576 | 📁 Comparing d09dba8 against main (4599335)

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4 files changed

± contents.html
± download.html
± library/http.cookies.html
± whatsnew/3.15.html

[tim-one]

Absolutely. To summarize why, the original change:

• Opened the door to a new exponential-time reDOS attack.
• Wasn't well defined: it allowed for ambiguous inputs. This can't be repaired (trying to remove the meta-meanings of both semicolon and unescapred double quote inside a double-quoted string value makes it impossible in some cases to know when the string was intended to end).

So there's no clear way to preserve the intent of the original change. It's not just a matter of rewriting the implementation - the intent was subtly incoherent.

If something "like" the intent is desired, it requires a different design.