From 5cbef66be0ac05f0a971456e3fa6df6e4cfd52a0 Mon Sep 17 00:00:00 2001
From: Tristan Swadell <tswadell@google.com>
Date: Tue, 30 Jul 2024 13:08:05 -0700
Subject: [PATCH] Prevent self-append for Issues (#988)

---
 cel/env.go      |  4 ++--
 cel/env_test.go | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/cel/env.go b/cel/env.go
index 17c52180..3af2b36f 100644
--- a/cel/env.go
+++ b/cel/env.go
@@ -760,10 +760,10 @@ func (i *Issues) Append(other *Issues) *Issues {
 	if i == nil {
 		return other
 	}
-	if other == nil {
+	if other == nil || i == other {
 		return i
 	}
-	return NewIssues(i.errs.Append(other.errs.GetErrors()))
+	return NewIssuesWithSourceInfo(i.errs.Append(other.errs.GetErrors()), i.info)
 }
 
 // String converts the issues to a suitable display string.
diff --git a/cel/env_test.go b/cel/env_test.go
index 3c3235c5..3fbdeac0 100644
--- a/cel/env_test.go
+++ b/cel/env_test.go
@@ -81,6 +81,21 @@ func TestIssuesEmpty(t *testing.T) {
 	}
 }
 
+func TestIssuesAppendSelf(t *testing.T) {
+	e, err := NewEnv()
+	if err != nil {
+		t.Fatalf("NewEnv() failed: %v", err)
+	}
+	_, iss := e.Compile("a")
+	if len(iss.Errors()) != 1 {
+		t.Errorf("iss.Errors() got %v, wanted 1 error", iss.Errors())
+	}
+	iss = iss.Append(iss)
+	if len(iss.Errors()) != 1 {
+		t.Errorf("iss.Errors() got %v, wanted 1 error", iss.Errors())
+	}
+}
+
 func TestIssues(t *testing.T) {
 	e, err := NewEnv()
 	if err != nil {