Fix crash rewriting relative document URI on ..// in querystring

[goosfrabba]

What

ArticleUrlRewriter.get_document_uri crashes when the document being rewritten (or a linked item) has a querystring that contains a .. segment, e.g. xtree.html?css=../../prg:

ValueError: '..' segment in 'host/common/nessComponents/xtree.html?css=../..' cannot be walked

This is the bug reported (and confirmed as legitimate by @benoit74) in openzim/warc2zim#380 — the rewriting code has since moved into this library, so the fix belongs here.

Why it happened

get_document_uri built the string path + "?" + querystring and handed it to PurePosixPath. PurePosixPath splits on / and treats .. as directory navigation, so any / or .. inside a querystring was interpreted as path structure. PurePosixPath.relative_to(..., walk_up=True) then raises ValueError as soon as it has to walk up through a .. segment coming from the querystring.

Fix

A querystring is part of the ZIM entry name (a leaf), not a navigable directory, so its content must not take part in the relative-path walk. The relative path is now computed from the path components only, and the querystring is re-appended (url-encoded together with the path) once the relative path is known.

Output is unchanged for querystrings that don't contain / or .. segments (verified by the existing test suite).

Tests

Added test_get_document_uri_querystring_segments covering .. in the document querystring (the crash case), .. in a linked item's querystring, and / in a querystring.

Before the fix (source reverted, test kept):

FAILED tests/rewriting/test_url_rewriting.py::...::test_get_document_uri_querystring_segments[dotdot_in_article_querystring]
E   ValueError: '..' segment in 'kiwix.org/common/sub/page.html?css=../..' cannot be walked

After the fix:

tests/rewriting/ .......................................... 477 passed

Full tests/rewriting/ suite passes; ruff==0.15.14 check + format clean.

---

Disclosure: implemented with the help of an AI coding assistant (Claude); verified locally with the included test.

Fixes openzim/warc2zim#380

[benoit74]

Thank you for the valuable PR.

Two things to fix to move PR forward:

• you've fixed URL rewriting in Python which is good ; we need to have the same logic and fixes applied to URL rewriting in Javascript (see

  python-scraperlib/javascript/src/wombatSetup.js

  Line 72 in 295fefc

  export function urlRewriteFunction(

  )
• your comments currently explain why you've done these changes ; they should be meant to help future maintainer which barely know about this PR ; for instance "it used to raide ValueError ..." is quite verbose and I don't feel like it help future maintainer, which probably does not care what the code used to misbehave at some point in the past.