Check that a test stanza is disabled before generating the rules

CHANGES.md

@@ -1,6 +1,9 @@
 3.5.0 (unreleased)
 ------------------
 
+- Check if a `tests` stanza is disabled before generating the rules (#6134,
+  fixes #6132, @voodoos)
+
 - Shadow alias module `Foo__` when building a library `Foo` (#6126, @rgrinberg)
 
 - Allow dune describe workspace to accept directories as arguments.

src/dune_rules/gen_rules.ml

@@ -111,15 +111,18 @@ end = struct
     | Alias alias ->
       let+ () = Simple_rules.alias sctx alias ~dir ~expander in
       empty_none
-    | Tests tests ->
-      let+ cctx, merlin =
-        Test_rules.rules tests ~sctx ~dir ~scope ~expander ~dir_contents
-      in
-      { merlin = Some merlin
-      ; cctx = Some (tests.exes.buildable.loc, cctx)
-      ; js = None
-      ; source_dirs = None
-      }
+    | Tests tests -> (
+      Expander.eval_blang expander tests.enabled_if >>= function
+      | false -> Memo.return empty_none
+      | true ->
+        let+ cctx, merlin =
+          Test_rules.rules tests ~sctx ~dir ~scope ~expander ~dir_contents
+        in
+        { merlin = Some merlin
+        ; cctx = Some (tests.exes.buildable.loc, cctx)
+        ; js = None
+        ; source_dirs = None
+        })
     | Copy_files { files = glob; _ } ->
       let* source_dirs =
         let loc = String_with_vars.loc glob in

test/blackbox-tests/test-cases/tests-stanza/github6132.t

@@ -0,0 +1,22 @@
+  $ cat >dune-project <<EOF
+  > (lang dune 3.0)
+  > EOF
+
+  $ cat >dune <<EOF
+  > (test
+  >  (name missing_test)
+  >  (modules missing_test)
+  >  (enabled_if false)
+  >  (libraries lib_not))
+  > 
+  > (library
+  >  (name lib_not)
+  >  (modules lib_not)
+  >  (enabled_if false))
+  > EOF
+  $ touch missing_test.ml
+
+The test [missing_test] depends on a library that is disabled, but that should
+not trigger any error since the test itself is disabled in the same way as the
+library it depends on.
+  $ dune build @all