Fixing cmpfunc: fix sort to distinguish prefix-overlapping query keys

[arpitguptagithub]

When one query key is a prefix of another (e.g. 'a' vs 'ab'), the comparison function returned 0 (equal), making --sort-query produce non-deterministic order for such pairs.

I fix it by returning the length difference when the common prefix matches, so shorter keys sort before longer ones.

Adding a test with prefix-overlapping query keys to verify deterministic sort order.

[Copilot]

Pull request overview

This PR fixes query sorting determinism in trurl by making the query-pair comparator distinguish strings where one is a prefix of the other, and adds a regression test intended to cover prefix-overlapping query keys.

Changes:

• Update cmpfunc to break ties when one query pair is a strict prefix of another (shorter sorts first).
• Add a new --sort-query test case intended to verify deterministic ordering with prefix-overlapping keys.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
trurl.c	Adjusts the qsort comparator so prefix-overlapping strings no longer compare equal.
tests.json	Adds a regression test for --sort-query ordering.

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[arpitguptagithub]

@bagder ig now this will be okay, have a look? please

[bagder]

This branch cannot be rebased due to conflicts

Please rebase your branch ontop of master and force-push

[arpitguptagithub]

FYI

I have added a regresiion test---sort-query with prefix-overlapping keys (ab=2&a=1&abc=3) verifying correct sort output (a=1&ab=2&abc=3).
and along with that also added a "excludes": ["uppercase-hex"] to 3 existing upstream tests (tests 52, 132, 172): These tests have lowercase hex in their expected output (%3d, %5c, %2f) but fail on CI builds linked against libcurl 8.20.0-DEV which produces uppercase hex (%3D, %5C, %2F) The output on the github Actions UI for test output made it very difficult to spot the actual difference.

anyhow adding the excludes annotation skips them on uppercase-hex builds, matching the pattern already used by other tests in the repo (e.g. tests around line 717).

These are pre-existing failures unrelated to the cmpfunc fix.

Hope thats fine.