From 5aaba213d426e67a0761c6dcb7a37d8663026d92 Mon Sep 17 00:00:00 2001
From: metagn <metagngn@gmail.com>
Date: Fri, 18 Apr 2025 06:32:49 +0300
Subject: [PATCH] account for invalid data in enum `$` on arc/orc (#24886)

closes #24875

Refc gives `0 (invalid data!)`, but since enum `$` procs on arc are
generated during enum declarations we might not have access to string
concatenation and integer `$`, so it generates a static string. Just
chose an empty string for this.
---
 compiler/enumtostr.nim          | 4 ++++
 tests/arc/tinvalidenumtostr.nim | 9 +++++++++
 2 files changed, 13 insertions(+)
 create mode 100644 tests/arc/tinvalidenumtostr.nim

diff --git a/compiler/enumtostr.nim b/compiler/enumtostr.nim
index dc516d2e52..2223be2ffb 100644
--- a/compiler/enumtostr.nim
+++ b/compiler/enumtostr.nim
@@ -33,6 +33,10 @@ proc genEnumToStrProc*(t: PType; info: TLineInfo; g: ModuleGraph; idgen: IdGener
     caseStmt.add newTree(nkOfBranch, newIntTypeNode(field.position, t),
       newTree(nkStmtList, newTree(nkFastAsgn, newSymNode(res), newStrNode(val, info))))
     #newIntTypeNode(nkIntLit, field.position, t)
+  # safety branch for invalid data:
+  caseStmt.add newTree(nkElse,
+    newTree(nkStmtList, newTree(nkFastAsgn, newSymNode(res),
+      newStrNode("", info))))
 
   body.add(caseStmt)
 
diff --git a/tests/arc/tinvalidenumtostr.nim b/tests/arc/tinvalidenumtostr.nim
new file mode 100644
index 0000000000..b053e30993
--- /dev/null
+++ b/tests/arc/tinvalidenumtostr.nim
@@ -0,0 +1,9 @@
+# issue #24875
+
+type
+  MyEnum = enum
+    One = 1
+
+var x = cast[MyEnum](0)
+let s = $x
+doAssert s == ""