Refactor find_probe() to use std::optional (#8334)

* Initial plan

* Refactor find_probe() to use std::optional

- Updated tactic_manager.h: Changed return type to std::optional<probe_info*>
- Updated tactic_manager.cpp: Modified implementation to return std::nullopt or probe pointer
- Updated api_tactic.cpp: Changed 2 call sites to use optional checks and dereference
- Updated tactic_cmds.cpp: Changed 1 call site to use optional check and dereference
- Build verified successfully
- Probe functionality tested with Python bindings

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

src/api/api_tactic.cpp

@@ -91,12 +91,12 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_mk_probe(c, name);
         RESET_ERROR_CODE();
-        probe_info * p = mk_c(c)->find_probe(symbol(name));
-        if (p == nullptr) {
+        auto p = mk_c(c)->find_probe(symbol(name));
+        if (!p) {
             SET_ERROR_CODE(Z3_INVALID_ARG, nullptr);
             RETURN_Z3(nullptr);
         }
-        probe * new_p = p->get();
+        probe * new_p = (*p)->get();
         RETURN_PROBE(new_p);
         Z3_CATCH_RETURN(nullptr);
     }
@@ -404,12 +404,12 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_probe_get_descr(c, name);
         RESET_ERROR_CODE();
-        probe_info * p = mk_c(c)->find_probe(symbol(name));
-        if (p == nullptr) {
+        auto p = mk_c(c)->find_probe(symbol(name));
+        if (!p) {
             SET_ERROR_CODE(Z3_INVALID_ARG, nullptr);
             return "";
         }
-        return p->get_descr();
+        return (*p)->get_descr();
         Z3_CATCH_RETURN("");
     }
 

src/cmd_context/tactic_cmds.cpp

@@ -767,9 +767,9 @@ MK_NARY_PROBE(mk_mul);
 
 probe * sexpr2probe(cmd_context & ctx, sexpr * n) {
     if (n->is_symbol()) {
-        probe_info * pinfo = ctx.find_probe(n->get_symbol());
-        if (pinfo != nullptr)
-            return pinfo->get();
+        auto pinfo = ctx.find_probe(n->get_symbol());
+        if (pinfo)
+            return (*pinfo)->get();
         throw cmd_exception("invalid probe, unknown builtin probe ", n->get_symbol(), n->get_line(), n->get_pos());
     }
     else if (n->is_numeral()) {

src/cmd_context/tactic_manager.cpp

@@ -70,9 +70,10 @@ simplifier_cmd * tactic_manager::find_simplifier_cmd(symbol const & s) const {
     return c;
 }
 
-probe_info * tactic_manager::find_probe(symbol const & s) const {
+std::optional<probe_info*> tactic_manager::find_probe(symbol const & s) const {
     probe_info * p = nullptr;
-    m_name2probe.find(s, p);
-    return p;
+    if (m_name2probe.find(s, p))
+        return p;
+    return std::nullopt;
 }
 

src/cmd_context/tactic_manager.h

@@ -38,7 +38,7 @@ public:
     void insert(simplifier_cmd* c);
     void insert(probe_info * p);
     std::optional<tactic_cmd*> find_tactic_cmd(symbol const & s) const; 
-    probe_info * find_probe(symbol const & s) const;     
+    std::optional<probe_info*> find_probe(symbol const & s) const;     
     simplifier_cmd* find_simplifier_cmd(symbol const& s) const;
 
     unsigned num_tactics() const { return m_tactics.size(); }