feat: add support for hidden bindings, transitive capture propagation, and UDF metadata improvements (#975)

Author: ziflex

pkg/compiler/debug_test.go

@@ -129,6 +129,48 @@ RETURN (
 	}
 }
 
+func TestDebugInfoHidesForwardingOnlyCaptures(t *testing.T) {
+	program, err := New(WithDebugInfo()).Compile(source.New("hidden_capture.fql", `
+LET base = 10
+FUNC target(value) => base + value
+FUNC forward(value) => target(value)
+RETURN forward(1)
+`))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	forwardID := -1
+	for id, fn := range program.Functions.UserDefined {
+		if fn.Name == "forward" {
+			forwardID = id
+			break
+		}
+	}
+
+	if forwardID < 0 {
+		t.Fatal("expected forward UDF metadata")
+	}
+
+	found := false
+	for _, point := range program.Metadata.DebugPoints {
+		if point.FunctionID != forwardID {
+			continue
+		}
+
+		found = true
+		for _, binding := range point.Bindings {
+			if binding.Name == "base" {
+				t.Fatalf("forwarding-only capture leaked into debugger bindings: %#v", point.Bindings)
+			}
+		}
+	}
+
+	if !found {
+		t.Fatal("expected forward UDF debug point")
+	}
+}
+
 func TestDebugInfoPreservesLexicalShadowing(t *testing.T) {
 	program, err := New(WithDebugInfo()).Compile(source.New("shadow.fql", `LET x = 1
 RETURN (

pkg/compiler/internal/binding_capture_info.go

@@ -1,9 +1,14 @@
 package internal
 
-import "github.com/antlr4-go/antlr/v4"
+import (
+	"github.com/antlr4-go/antlr/v4"
+
+	"github.com/MontFerret/ferret/v2/pkg/compiler/internal/core"
+)
 
 type captureBindingInfo struct {
 	Decl    antlr.ParserRuleContext
 	Name    string
+	ID      core.BindingID
 	Mutable bool
 }

pkg/compiler/internal/binding_compiler.go

@@ -79,6 +79,7 @@ func (c *BindingCompiler) CompileVariableDeclaration(ctx fql.IVariableDeclaratio
 	}
 
 	opts := core.BindingOptions{
+		ID:      bindingIDFromRule(decl),
 		Mutable: mutable,
 		Storage: storage,
 	}
@@ -228,6 +229,7 @@ func (c *BindingCompiler) captureBindingForDeclaration(ctx fql.IVariableDeclarat
 		Name:    c.declarationName(ctx),
 		Mutable: c.isMutableDeclaration(ctx),
 		Decl:    ctx.(antlr.ParserRuleContext),
+		ID:      bindingIDFromRule(ctx.(antlr.ParserRuleContext)),
 	}
 }
 

pkg/compiler/internal/call_resolver.go

@@ -88,12 +88,21 @@ func (r *CallResolver) ResolveUDF(ctx fql.IFunctionCallContext) (*core.UDFInfo,
 		return nil, false
 	}
 
+	return r.ResolveUDFInScope(ctx, r.session.Function.UDFScope)
+}
+
+// ResolveUDFInScope resolves an unqualified source call against an explicit lexical UDF scope.
+func (r *CallResolver) ResolveUDFInScope(ctx fql.IFunctionCallContext, scope *core.UDFScope) (*core.UDFInfo, bool) {
+	if r == nil || r.session == nil || r.session.Program.UDFs == nil || scope == nil {
+		return nil, false
+	}
+
 	name, ok := r.ResolveLocalFunctionName(ctx)
 	if !ok {
 		return nil, false
 	}
 
-	return r.session.Program.UDFs.Resolve(name, r.session.Function.UDFScope)
+	return r.session.Program.UDFs.Resolve(name, scope)
 }
 
 func (r *CallResolver) applyNamespaceAlias(ns string) string {