From 4e498b43033a3db448653edc0538873bbbc4cc4e Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Mon, 10 Apr 2023 22:09:27 +0800
Subject: [PATCH] cgen: fix printing array of recursive reference struct (fix
 #17858) (#17922)

---
 vlib/v/gen/c/auto_str_methods.v                | 14 +++++++++++++-
 ...ing_recursive_array_of_reference_struct.out |  5 +++++
 ...ting_recursive_array_of_reference_struct.vv | 18 ++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.out
 create mode 100644 vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.vv

diff --git a/vlib/v/gen/c/auto_str_methods.v b/vlib/v/gen/c/auto_str_methods.v
index b78d4e87cf..23bdd44878 100644
--- a/vlib/v/gen/c/auto_str_methods.v
+++ b/vlib/v/gen/c/auto_str_methods.v
@@ -969,9 +969,21 @@ fn (mut g Gen) gen_str_for_struct(info ast.Struct, styp string, typ_str string,
 				funcprefix += '*'
 			}
 		}
+		mut is_field_array := false
+		if sym.info is ast.Array {
+			field_styp = g.typ(sym.info.elem_type).trim('*')
+			is_field_array = true
+		} else if sym.info is ast.ArrayFixed {
+			field_styp = g.typ(sym.info.elem_type).trim('*')
+			is_field_array = true
+		}
 		// handle circular ref type of struct to the struct itself
 		if styp == field_styp && !allow_circular {
-			fn_body.write_string('${funcprefix}_SLIT("<circular>")')
+			if is_field_array {
+				fn_body.write_string('it.${c_name(field.name)}.len > 0 ? ${funcprefix}_SLIT("[<circular>]") : ${funcprefix}_SLIT("[]")')
+			} else {
+				fn_body.write_string('${funcprefix}_SLIT("<circular>")')
+			}
 		} else {
 			// manage C charptr
 			if field.typ in ast.charptr_types {
diff --git a/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.out b/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.out
new file mode 100644
index 0000000000..d7072d2fb7
--- /dev/null
+++ b/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.out
@@ -0,0 +1,5 @@
+&Person{
+    name: 'John'
+    relatives: [<circular>]
+}
+Success
diff --git a/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.vv b/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.vv
new file mode 100644
index 0000000000..d9a716ddf5
--- /dev/null
+++ b/vlib/v/slow_tests/inout/printing_recursive_array_of_reference_struct.vv
@@ -0,0 +1,18 @@
+struct Person {
+	name string
+mut:
+	relatives []&Person
+}
+
+fn main() {
+	mut father := &Person{
+		name: 'John'
+	}
+	mut mother := &Person{
+		name: 'Jane'
+		relatives: [father]
+	}
+	father.relatives = [mother]
+	println(father)
+	println('Success')
+}