1. Manager decides worker’s lease is stale.
2. It records/sends lease cancel.
3. Worker finishes naturally before observing
4. Worker releases/discards old lease.
5. The lease-cancel counter is still sitting on the worker limit.
6. Later, a naked m.inc() check sees that stale cancel and treats it as global cancellation.
The C++ implementation of the fixedpoint engine (in
z3/src/api/api_datalog.cpp) already attempts to read `rlimit` from its
local parameters:
```c++
unsigned rlimit = to_fixedpoint(d)->m_params.get_uint("rlimit", mk_c(c)->get_rlimit());
```
However, because `rlimit` was not registered in the public fp parameter
schema (`fp_params.pyg`), any attempt by clients to set it locally via
`Z3_fixedpoint_set_params` was rejected by the Z3 parameter validator
with an "unknown parameter" error.
Implements the algorithm of Eq(p,q) = Empty(p XOR q)' using a union-find
driven bisimulation closure (per the CAV'26 ERE paper).
### What's added
* **New primitive OP_RE_XOR (re.xor)** wired through seq_decl_plugin:
parser signature, info propagation (nullable, min_length), and
pretty-printer.
* **seq_rewriter**: structural XOR rewrites ( XOR r = empty, XOR empty =
r, ull XOR r = comp(r), comp/comp absorption, complement push, AC
normalisation), nullability (Null(p XOR q) = Null(p) != Null(q)),
derivative (D_a(p XOR q) = D_a(p) XOR D_a(q)), reverse, antimirov
derivative, and `check_deriv_normal_form` coverage.
* **New class seq::regex_bisim** in
`src/ast/rewriter/seq_regex_bisim.{h,cpp}` to keep the bisim logic out
of the already-large `seq_rewriter.cpp`. Uses `basic_union_find` from
`util/union_find.h`, an `obj_map` for the node assignment, and a
50000-step bound (returns `l_undef` on overrun).
* **Integration** in `seq_rewriter::reduce_re_eq` (with a re-entry
guard) and in `seq_regex::propagate_eq` / `propagate_ne` for ground
regexes; on `l_undef` we fall back to the existing axiomatisation.
* **`sls_seq_plugin`**: extend `OP_RE_DIFF` switch arms to also cover
`OP_RE_XOR`.
### Validation
* Full release build with MSVC + Ninja.
* `./test-z3 /a` -- 89/89 tests passing.
* `./test-z3 /seq smt2print_parse` -- PASS.
* Smoke tests with `(a|b)*` vs `(a*b*)*` (equal) and `a*` vs `(a|b)*`
(not equal) return the expected `sat`/`unsat` quickly.
---------
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Bumps [shell-quote](https://github.com/ljharb/shell-quote) from 1.7.3 to
1.8.4.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/ljharb/shell-quote/blob/main/CHANGELOG.md">shell-quote's
changelog</a>.</em></p>
<blockquote>
<h2><a
href="https://github.com/ljharb/shell-quote/compare/v1.8.3...v1.8.4">v1.8.4</a>
- 2026-05-22</h2>
<h3>Commits</h3>
<ul>
<li>[Fix] <code>quote</code>: validate object-token shapes <a
href="4378a6e613"><code>4378a6e</code></a></li>
<li>[Dev Deps] update <code>@ljharb/eslint-config</code>,
<code>auto-changelog</code>, <code>eslint</code>, <code>npmignore</code>
<a
href="22ebec0434"><code>22ebec0</code></a></li>
<li>[Tests] increase coverage <a
href="9f3caa3190"><code>9f3caa3</code></a></li>
<li>[readme] replace runkit CI badge with shields.io check-runs badge <a
href="3344a047dd"><code>3344a04</code></a></li>
<li>[Dev Deps] update <code>@ljharb/eslint-config</code> <a
href="699c5113d1"><code>699c511</code></a></li>
</ul>
<h2><a
href="https://github.com/ljharb/shell-quote/compare/v1.8.2...v1.8.3">v1.8.3</a>
- 2025-06-01</h2>
<h3>Fixed</h3>
<ul>
<li>[Fix] remove unnecessary backslash escaping in single quotes <a
href="https://redirect.github.com/ljharb/shell-quote/issues/15"><code>[#15](https://github.com/ljharb/shell-quote/issues/15)</code></a></li>
</ul>
<h2><a
href="https://github.com/ljharb/shell-quote/compare/v1.8.1...v1.8.2">v1.8.2</a>
- 2024-11-27</h2>
<h3>Fixed</h3>
<ul>
<li>[Fix] <code>quote</code>: preserve empty strings <a
href="https://redirect.github.com/ljharb/shell-quote/issues/18"><code>[#18](https://github.com/ljharb/shell-quote/issues/18)</code></a></li>
</ul>
<h3>Commits</h3>
<ul>
<li>[meta] fix changelog tags <a
href="0fb9fd8441"><code>0fb9fd8</code></a></li>
<li>[actions] split out node 10-20, and 20+ <a
href="819bd842e0"><code>819bd84</code></a></li>
<li>[Dev Deps] update <code>@ljharb/eslint-config</code>,
<code>auto-changelog</code>, <code>npmignore</code>, <code>tape</code>
<a
href="fc564086c8"><code>fc56408</code></a></li>
<li>[actions] update npm for windows tests <a
href="fdeb0fd102"><code>fdeb0fd</code></a></li>
<li>[Dev Deps] update <code>@ljharb/eslint-config</code>,
<code>aud</code>, <code>tape</code> <a
href="b8a4a3b3f5"><code>b8a4a3b</code></a></li>
<li>[actions] prevent node 14 on ARM mac from failing <a
href="9eecafc048"><code>9eecafc</code></a></li>
<li>[meta] exclude more files from the package <a
href="4044e7fad4"><code>4044e7f</code></a></li>
<li>[Tests] replace <code>aud</code> with <code>npm audit</code> <a
href="8cfdbd8ec3"><code>8cfdbd8</code></a></li>
<li>[meta] add missing <code>engines.node</code> <a
href="843820e1a4"><code>843820e</code></a></li>
<li>[Dev Deps] add missing peer dep <a
href="4c3b88d792"><code>4c3b88d</code></a></li>
<li>[Dev Deps] pin <code>jackspeak</code> since 2.1.2+ depends on npm
aliases, which kill the install process in npm < 6 <a
href="80322ed591"><code>80322ed</code></a></li>
</ul>
<h2><a
href="https://github.com/ljharb/shell-quote/compare/v1.8.0...v1.8.1">v1.8.1</a>
- 2023-04-07</h2>
<h3>Fixed</h3>
<ul>
<li>[Fix] <code>parse</code>: preserve whitespace in comments <a
href="https://redirect.github.com/ljharb/shell-quote/issues/6"><code>[#6](https://github.com/ljharb/shell-quote/issues/6)</code></a></li>
<li>[Fix] properly support the <code>escape</code> option <a
href="https://redirect.github.com/ljharb/shell-quote/issues/5"><code>[#5](https://github.com/ljharb/shell-quote/issues/5)</code></a></li>
</ul>
<h3>Commits</h3>
<ul>
<li>[Refactor] <code>parse</code>: hoist <code>getVar</code> to module
level <a
href="b42ac73e39"><code>b42ac73</code></a></li>
<li>[Refactor] hoist some vars to module level <a
href="8f0c5c3c9d"><code>8f0c5c3</code></a></li>
<li>[Refactor] <code>parse</code>: use <code>slice</code> over
<code>substr</code>, cache some values <a
href="fcb2e1acd5"><code>fcb2e1a</code></a></li>
<li>[Refactor] <code>parse</code>: a bit of cleanup <a
href="6780ec5194"><code>6780ec5</code></a></li>
<li>[Refactor] <code>parse</code>: tweak the regex to not match nothing
<a
href="227d4742a0"><code>227d474</code></a></li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="ff166e2b63"><code>ff166e2</code></a>
v1.8.4</li>
<li><a
href="4378a6e613"><code>4378a6e</code></a>
[Fix] <code>quote</code>: validate object-token shapes</li>
<li><a
href="22ebec0434"><code>22ebec0</code></a>
[Dev Deps] update <code>@ljharb/eslint-config</code>,
<code>auto-changelog</code>, <code>eslint</code>, `npmig...</li>
<li><a
href="9f3caa3190"><code>9f3caa3</code></a>
[Tests] increase coverage</li>
<li><a
href="3344a047dd"><code>3344a04</code></a>
[readme] replace runkit CI badge with shields.io check-runs badge</li>
<li><a
href="699c5113d1"><code>699c511</code></a>
[Dev Deps] update <code>@ljharb/eslint-config</code></li>
<li><a
href="487a9b41a7"><code>487a9b4</code></a>
v1.8.3</li>
<li><a
href="01faafff97"><code>01faaff</code></a>
[Fix] remove unnecessary backslash escaping in single quotes</li>
<li><a
href="b19fc77e66"><code>b19fc77</code></a>
v1.8.2</li>
<li><a
href="59d29ea694"><code>59d29ea</code></a>
[Fix] <code>quote</code>: preserve empty strings</li>
<li>Additional commits viewable in <a
href="https://github.com/ljharb/shell-quote/compare/v1.7.3...v1.8.4">compare
view</a></li>
</ul>
</details>
<details>
<summary>Maintainer changes</summary>
<p>This version was pushed to npm by <a
href="https://www.npmjs.com/~ljharb">ljharb</a>, a new releaser for
shell-quote since your current version.</p>
</details>
<details>
<summary>Install script changes</summary>
<p>This version adds <code>prepublish</code> script that runs during
installation. Review the package contents before updating.</p>
</details>
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