Test for issue #7454: fmt triggers menhir

test/blackbox-tests/test-cases/formatting/no-gen.t

@@ -0,0 +1,75 @@
+See issue 7454
+
+  $ cat >parser_raw.mly <<EOF
+  > %token EOL
+  > %start <unit> prog
+  > %%
+  > prog:
+  >   | EOL { () } 
+  >   | EOL; prog { () } 
+  > EOF
+
+  $ cat >dune <<EOF
+  > (library 
+  >  (name foo)
+  >  (modules parser_raw other_gen))
+  > 
+  > (menhir
+  >  (modules parser_raw)
+  >  (mode promote))
+  > 
+  > (rule
+  >  (targets other_gen.ml)
+  >  (mode promote)
+  >  (action (with-stdout-to %{targets}
+  >          (echo "print_int 42"))))
+  > EOF
+
+  $ cat >dune-project <<EOF
+  > (lang dune 2.9)
+  > (using menhir 2.0)
+  > (formatting (enabled_for ocaml))
+  > EOF
+
+  $ touch .ocamlformat 
+
+In the above project, two modules have their implementation generated: 
+- [Other_gen]'s implementation is generated by a rule stanza
+- [Parser_raw]'s implementation is genrated by menhir stanza
+
+Formatting the codebase should not trigger the generation of missing modules
+  $ dune build @fmt
+
+As expected, Dune did not try to generate the missing implem for [Parser_raw] 
+  $ dune_cmd exists _build/default/parser_raw.ml
+  false
+
+As expected, Dune did not try to generate the missing implem for [Other_gen]
+  $ dune_cmd exists _build/default/other_gen.ml
+  false
+
+  $ dune clean
+
+Now we add [mli] files for the two modules whose implementation is generated:
+
+  $ touch other_gen.mli
+  $ touch parser_raw.mli 
+
+We format again.
+  $ dune build @fmt
+  Warning: one state end-of-stream conflict was arbitrarily resolved.
+  File "parser_raw.mly", line 5, characters 4-7:
+  Warning: production prog -> EOL is never reduced.
+  Warning: in total, 1 production is never reduced.
+  File "parser_raw.mli", line 1, characters 0-0:
+  Error: Files _build/default/parser_raw.mli and
+  _build/default/.formatted/parser_raw.mli differ.
+  [1]
+
+FIXME: unexpectedly, Dune generated the missing parser
+  $ dune_cmd exists _build/default/parser_raw.ml
+  true
+
+As expected, Dune did not try to generate the missing implem for [Other_gen]
+  $ dune_cmd exists _build/default/other_gen.ml
+  false