From ed9a01dda4d67f463d248a8f30d19ef3f3f54ac9 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2026 05:58:20 +0300
Subject: [PATCH] cgen: fix `bad address` error when using `os.execve()` (fixes
 #26007)

---
 vlib/v/gen/c/struct.v                         |  7 +++-
 ...struct_init_result_propagation.c.must_have |  2 +
 .../heap_struct_init_result_propagation.vv    | 39 +++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/gen/c/testdata/heap_struct_init_result_propagation.c.must_have
 create mode 100644 vlib/v/gen/c/testdata/heap_struct_init_result_propagation.vv

diff --git a/vlib/v/gen/c/struct.v b/vlib/v/gen/c/struct.v
index 06dacfc04..6351128b4 100644
--- a/vlib/v/gen/c/struct.v
+++ b/vlib/v/gen/c/struct.v
@@ -462,7 +462,7 @@ fn (mut g Gen) struct_init(node ast.StructInit) {
 	}
 }
 
-fn (g &Gen) can_use_direct_heap_struct_init(node ast.StructInit, sym ast.TypeSymbol, aligned int, const_msvc_init bool) bool {
+fn (mut g Gen) can_use_direct_heap_struct_init(node ast.StructInit, sym ast.TypeSymbol, aligned int, const_msvc_init bool) bool {
 	if g.is_shared || g.inside_cast_in_heap > 0 || g.inside_cinit || g.inside_const
 		|| g.inside_global_decl || aligned != 0 || const_msvc_init || node.typ.has_flag(.option)
 		|| node.has_update_expr || sym.kind != .struct {
@@ -476,6 +476,11 @@ fn (g &Gen) can_use_direct_heap_struct_init(node ast.StructInit, sym ast.TypeSym
 		|| node.init_fields.len != info.fields.len {
 		return false
 	}
+	for init_field in node.init_fields {
+		if g.need_tmp_var_in_expr(init_field.expr) {
+			return false
+		}
+	}
 	if node.no_keys {
 		return true
 	}
diff --git a/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.c.must_have b/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.c.must_have
new file mode 100644
index 000000000..378cf325a
--- /dev/null
+++ b/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.c.must_have
@@ -0,0 +1,2 @@
+c->process = (HEAP(main__Process, ((main__Process){.path = (*(string*)
+,.argv = c->args,.dir = c->dir,})));
diff --git a/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.vv b/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.vv
new file mode 100644
index 000000000..1460d7bd7
--- /dev/null
+++ b/vlib/v/gen/c/testdata/heap_struct_init_result_propagation.vv
@@ -0,0 +1,39 @@
+// vtest vflags: -prod
+import os
+
+struct Process {
+	path string
+	argv []string
+	dir  string
+}
+
+struct Command {
+	path string
+	args []string
+	dir  string
+mut:
+	process &Process = unsafe { nil }
+}
+
+fn lookup(cmd string) !string {
+	return os.find_abs_path_of_executable(cmd)!
+}
+
+fn build(mut c Command) ! {
+	if !isnil(c.process) {
+		return error('reuse')
+	}
+	c.process = &Process{
+		path: lookup(c.path)!
+		argv: c.args
+		dir:  c.dir
+	}
+}
+
+fn main() {
+	mut cmd := Command{
+		path: 'bash'
+		args: ['-c', 'echo ok']
+	}
+	build(mut cmd) or { panic(err) }
+}
-- 
2.39.5