feat: expose issue error offsets

cel/env.go

@@ -1009,6 +1009,41 @@ func (i *Issues) Errors() []*Error {
 	return i.errs.GetErrors()
 }
 
+// Source returns the source associated with the issues.
+func (i *Issues) Source() Source {
+	if i == nil {
+		return nil
+	}
+	return i.errs.Source()
+}
+
+// ErrorOffset returns the start character offset for the error, if available.
+func (i *Issues) ErrorOffset(err *Error) (int32, bool) {
+	offsetRange, found := i.ErrorOffsetRange(err)
+	if found {
+		return offsetRange.Start, true
+	}
+	return 0, false
+}
+
+// ErrorOffsetRange returns the character offset range for the error, if available.
+func (i *Issues) ErrorOffsetRange(err *Error) (celast.OffsetRange, bool) {
+	if i == nil || err == nil {
+		return celast.OffsetRange{}, false
+	}
+	if i.info != nil {
+		if offsetRange, found := i.info.GetOffsetRange(err.ExprID); found {
+			return offsetRange, true
+		}
+	}
+	if src := i.Source(); src != nil {
+		if offset, found := src.LocationOffset(err.Location); found {
+			return celast.OffsetRange{Start: offset, Stop: offset}, true
+		}
+	}
+	return celast.OffsetRange{}, false
+}
+
 // Append collects the issues from another Issues struct into a new Issues object.
 func (i *Issues) Append(other *Issues) *Issues {
 	if i == nil {

cel/env_test.go

@@ -140,6 +140,38 @@ ERROR: <input>:1:2: Syntax error: mismatched input '<EOF>' expecting {'[', '{',
 	}
 }
 
+func TestIssuesErrorOffsetRange(t *testing.T) {
+	e, err := NewEnv()
+	if err != nil {
+		t.Fatalf("NewEnv() failed: %v", err)
+	}
+	_, iss := e.Compile("missing")
+	if len(iss.Errors()) != 1 {
+		t.Fatalf("iss.Errors() got %v, wanted 1 error", iss.Errors())
+	}
+	errInfo := iss.Errors()[0]
+
+	offset, found := iss.ErrorOffset(errInfo)
+	if !found {
+		t.Fatal("ErrorOffset() got found false, wanted true")
+	}
+	if offset != 0 {
+		t.Errorf("ErrorOffset() got %d, wanted 0", offset)
+	}
+
+	offsetRange, found := iss.ErrorOffsetRange(errInfo)
+	if !found {
+		t.Fatal("ErrorOffsetRange() got found false, wanted true")
+	}
+	if offsetRange != (ast.OffsetRange{Start: 0, Stop: 7}) {
+		t.Errorf("ErrorOffsetRange() got %v, wanted [0, 7]", offsetRange)
+	}
+
+	if iss.Source() == nil {
+		t.Fatal("Source() got nil, wanted source")
+	}
+}
+
 func TestFormatCELTypeEquivalence(t *testing.T) {
 	values := []*Type{
 		AnyType,

common/errors.go

@@ -70,6 +70,11 @@ func (e *Errors) GetErrors() []*Error {
 	return e.errors[:]
 }
 
+// Source returns the source associated with the errors.
+func (e *Errors) Source() Source {
+	return e.source
+}
+
 // Append creates a new Errors object with the current and input errors.
 func (e *Errors) Append(errs []*Error) *Errors {
 	return &Errors{