From 087eeaf33c7cd335449017ab06a7ad3f02080639 Mon Sep 17 00:00:00 2001
From: Copilot <198982749+Copilot@users.noreply.github.com>
Date: Sun, 12 Jul 2026 20:32:02 -0700
Subject: [PATCH] Fix api_datalog test: reuse of Z3_context across set-logic
 calls (#10101)
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The `api_datalog` unit test was failing in CI with `"the logic has
already been set"`. Two consecutive regression tests shared a single
`Z3_context`, but both called `Z3_eval_smtlib2_string` with `(set-logic
HORN)` — the second call always fails because context logic state is
permanent.

## Changes

- **`src/test/api_datalog.cpp`**: Give each
`Z3_eval_smtlib2_string`-based regression test its own
`Z3_config`/`Z3_context`, destroyed immediately after the test block.
The outer context is retained only for the two tests that don't invoke
the SMT-LIB evaluator.

```cpp
// Before: both blocks shared `ctx`, second (set-logic HORN) always errored
Z3_string response = Z3_eval_smtlib2_string(ctx, chc1);  // sets HORN logic
Z3_string response = Z3_eval_smtlib2_string(ctx, chc2);  // ERROR: logic already set

// After: each block owns its context
Z3_config cfg2 = Z3_mk_config();
Z3_context ctx2 = Z3_mk_context(cfg2);
Z3_del_config(cfg2);
Z3_string response = Z3_eval_smtlib2_string(ctx2, chc2);
Z3_del_context(ctx2);
```

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
---
 src/test/api_datalog.cpp | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/test/api_datalog.cpp b/src/test/api_datalog.cpp
index 3b0011a4b3..f57e0c0419 100644
--- a/src/test/api_datalog.cpp
+++ b/src/test/api_datalog.cpp
@@ -66,6 +66,10 @@ void tst_api_datalog() {
 
     // Regression test for Spacer model construction on ADT CHCs
     {
+        Z3_config cfg2 = Z3_mk_config();
+        Z3_context ctx2 = Z3_mk_context(cfg2);
+        Z3_del_config(cfg2);
+
         char const* chc =
             "(set-logic HORN)\n"
             "(set-option :fp.engine spacer)\n"
@@ -85,13 +89,18 @@ void tst_api_datalog() {
             "      false)))\n"
             "(check-sat)\n";
 
-        Z3_string response = Z3_eval_smtlib2_string(ctx, chc);
+        Z3_string response = Z3_eval_smtlib2_string(ctx2, chc);
         ENSURE(response != nullptr);
-        ENSURE(Z3_get_error_code(ctx) == Z3_OK);
+        ENSURE(Z3_get_error_code(ctx2) == Z3_OK);
+        Z3_del_context(ctx2);
     }
 
     // Regression test for assertion violation in Spacer QE projection (#3845)
     {
+        Z3_config cfg3 = Z3_mk_config();
+        Z3_context ctx3 = Z3_mk_context(cfg3);
+        Z3_del_config(cfg3);
+
         char const* chc = R"(
 (set-logic HORN)
 (set-option :fp.xform.inline_eager false)
@@ -224,9 +233,10 @@ void tst_api_datalog() {
 (check-sat)
 )";
 
-        Z3_string response = Z3_eval_smtlib2_string(ctx, chc);
+        Z3_string response = Z3_eval_smtlib2_string(ctx3, chc);
         ENSURE(response != nullptr);
-        ENSURE(Z3_get_error_code(ctx) == Z3_OK);
+        ENSURE(Z3_get_error_code(ctx3) == Z3_OK);
+        Z3_del_context(ctx3);
     }
 
     Z3_del_context(ctx);