test: reproduction case for #12535

test/blackbox-tests/test-cases/dune

@@ -38,6 +38,12 @@
  (applies_to windows-diff github6644)
  (alias runtest-windows))
 
+(cram
+ (applies_to windows-artifacts-duplicate-install)
+ (alias runtest-windows)
+ (enabled_if
+  (= %{os_type} "Win32")))
+
 ;; DISABLED TESTS
 
 (subdir

test/blackbox-tests/test-cases/windows-artifacts-duplicate-install.t

@@ -0,0 +1,42 @@
+Reproduction case for Windows artifacts duplicate key crash
+https://github.com/ocaml/dune/issues/12535
+
+When an install stanza contains both `name.exe` and `name` (e.g., the
+executable and a wrapper script), The Windows handling in Dune strips the
+`.exe` suffix in artifacts.ml, causing both to become "name", leading to
+duplicate keys in the artifacts map.
+
+  $ cat > dune-project <<EOF
+  > (lang dune 3.21)
+  > (package
+  >  (name myapp))
+  > EOF
+
+  $ cat > dune <<EOF
+  > (executable
+  >  (name myapp)
+  >  (public_name myapp))
+  > 
+  > (install
+  >  (section bin)
+  >  (files
+  >   myapp.exe
+  >   myapp))
+  > EOF
+
+  $ cat > myapp.ml <<EOF
+  > let () = print_endline "Hello from myapp"
+  > EOF
+
+Wrapper script:
+  $ cat > myapp <<'EOF'
+  > #!/bin/sh
+  > exec $(dirname $0)/myapp.exe "$@"
+  > EOF
+  $ chmod +x myapp
+
+On Windows, this should not crash with duplicate "myapp" keys.
+
+  $ dune build myapp.install 2>&1 | grep "Internal"
+  Internal error, please report upstream including the contents of _build/log.
+