Merge pull request #8755 from Z3Prover/copilot/simplify-go-propagator-callbacks

Simplify Go user propagator callbacks with `withCallback` helper

src/api/go/propagator_callbacks.go

@@ -10,15 +10,20 @@ import (
 	"unsafe"
 )
 
+// withCallback temporarily sets the callback context, calls fn, and restores the old context.
+func (p *UserPropagator) withCallback(cb C.Z3_solver_callback, fn func()) {
+	old := p.cb
+	p.cb = cb
+	defer func() { p.cb = old }()
+	fn()
+}
+
 // goPushCb is exported to C as a callback for Z3_push_eh.
 //
 //export goPushCb
 func goPushCb(ctx C.uintptr_t, cb C.Z3_solver_callback) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
-	old := p.cb
+	p.withCallback(cb, p.iface.Push)
-	p.cb = cb
-	defer func() { p.cb = old }()
-	p.iface.Push()
 }
 
 // goPopCb is exported to C as a callback for Z3_pop_eh.
@@ -26,10 +31,9 @@ func goPushCb(ctx C.uintptr_t, cb C.Z3_solver_callback) {
 //export goPopCb
 func goPopCb(ctx C.uintptr_t, cb C.Z3_solver_callback, numScopes C.uint) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
-	old := p.cb
+	p.withCallback(cb, func() {
-	p.cb = cb
+		p.iface.Pop(uint(numScopes))
-	defer func() { p.cb = old }()
+	})
-	p.iface.Pop(uint(numScopes))
 }
 
 // goFreshCb is exported to C as a callback for Z3_fresh_eh.
@@ -53,10 +57,9 @@ func goFreshCb(ctx C.uintptr_t, newContext C.Z3_context) C.uintptr_t {
 func goFixedCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast, value C.Z3_ast) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(FixedHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			h.Fixed(newExpr(p.ctx, t), newExpr(p.ctx, value))
-		defer func() { p.cb = old }()
+		})
-		h.Fixed(newExpr(p.ctx, t), newExpr(p.ctx, value))
 	}
 }
 
@@ -66,10 +69,9 @@ func goFixedCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast, value C.Z3_
 func goEqCb(ctx C.uintptr_t, cb C.Z3_solver_callback, s C.Z3_ast, t C.Z3_ast) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(EqHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			h.Eq(newExpr(p.ctx, s), newExpr(p.ctx, t))
-		defer func() { p.cb = old }()
+		})
-		h.Eq(newExpr(p.ctx, s), newExpr(p.ctx, t))
 	}
 }
 
@@ -79,10 +81,9 @@ func goEqCb(ctx C.uintptr_t, cb C.Z3_solver_callback, s C.Z3_ast, t C.Z3_ast) {
 func goDiseqCb(ctx C.uintptr_t, cb C.Z3_solver_callback, s C.Z3_ast, t C.Z3_ast) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(DiseqHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			h.Diseq(newExpr(p.ctx, s), newExpr(p.ctx, t))
-		defer func() { p.cb = old }()
+		})
-		h.Diseq(newExpr(p.ctx, s), newExpr(p.ctx, t))
 	}
 }
 
@@ -92,10 +93,7 @@ func goDiseqCb(ctx C.uintptr_t, cb C.Z3_solver_callback, s C.Z3_ast, t C.Z3_ast)
 func goFinalCb(ctx C.uintptr_t, cb C.Z3_solver_callback) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(FinalHandler); ok {
-		old := p.cb
+		p.withCallback(cb, h.Final)
-		p.cb = cb
-		defer func() { p.cb = old }()
-		h.Final()
 	}
 }
 
@@ -105,10 +103,9 @@ func goFinalCb(ctx C.uintptr_t, cb C.Z3_solver_callback) {
 func goCreatedCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(CreatedHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			h.Created(newExpr(p.ctx, t))
-		defer func() { p.cb = old }()
+		})
-		h.Created(newExpr(p.ctx, t))
 	}
 }
 
@@ -118,10 +115,9 @@ func goCreatedCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast) {
 func goDecideCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast, idx C.uint, phase C.bool) {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
 	if h, ok := p.iface.(DecideHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			h.Decide(newExpr(p.ctx, t), uint(idx), phase == C.bool(true))
-		defer func() { p.cb = old }()
+		})
-		h.Decide(newExpr(p.ctx, t), uint(idx), phase == C.bool(true))
 	}
 }
 
@@ -130,13 +126,15 @@ func goDecideCb(ctx C.uintptr_t, cb C.Z3_solver_callback, t C.Z3_ast, idx C.uint
 //export goOnBindingCb
 func goOnBindingCb(ctx C.uintptr_t, cb C.Z3_solver_callback, q C.Z3_ast, inst C.Z3_ast) C.bool {
 	p := cgo.Handle(ctx).Value().(*UserPropagator)
+	result := C.bool(true) // default: allow binding when handler is not implemented
 	if h, ok := p.iface.(OnBindingHandler); ok {
-		old := p.cb
+		p.withCallback(cb, func() {
-		p.cb = cb
+			if !h.OnBinding(newExpr(p.ctx, q), newExpr(p.ctx, inst)) {
-		defer func() { p.cb = old }()
+				result = C.bool(false)
-		return C.bool(h.OnBinding(newExpr(p.ctx, q), newExpr(p.ctx, inst)))
+			}
+		})
 	}
-	return C.bool(true)
+	return result
 }
 
 // goOnClauseCb is exported to C as a callback for Z3_on_clause_eh.