Always include include-blocks but not execute when skip is used

lib/block.ml

@@ -562,12 +562,18 @@ let from_raw raw =
            ~delim:None
 
 let is_active ?section:s t =
-  let active =
+  let active_section =
     match s with
     | Some p -> (
         match t.section with
         | Some s -> Re.execp (Re.Perl.compile_pat p) (snd s)
         | None -> Re.execp (Re.Perl.compile_pat p) "")
     | None -> true
   in
-  active && t.version_enabled && t.os_type_enabled && not t.skip
+  let can_update_content =
+    match t.value with
+    (* include blocks are always updated even if not executed *)
+    | Include _ -> true
+    | _ -> not t.skip
+  in
+  active_section && t.version_enabled && t.os_type_enabled && can_update_content

lib/test/mdx_test.ml

@@ -368,6 +368,8 @@ let run_exn ~non_deterministic ~silent_eval ~record_backtrace ~syntax ~silent
           in
           let updated_block =
             match ocaml_value with
+            (* including without executing *)
+            | Some _ when t.skip -> new_block
             | Some ocaml_value -> run_ocaml_value new_block ocaml_value
             | _ -> new_block
           in

test/bin/mdx-test/expect/exec-include/test-case.md

@@ -4,9 +4,10 @@
 val f : int -> int
 ```
 
-Use `skip` to not include the .mli files:
+.mli files are still included when `skip` is used:
 <!-- $MDX file=code.mli,skip -->
 ```ocaml
+val f : int -> int
 ```
 
 .ml files are included and executed:
@@ -24,11 +25,14 @@ Line 1, characters 9-10:
 Error: Unbound value x
 ```
 
-Use `skip` to not include the .ml files:
+
+.ml files are still included but no longer executed when `skip` is used:
 <!-- $MDX file=code.ml,part=OK,skip -->
 ```ocaml
+let f x = x + 1
 ```
 
 <!-- $MDX file=code.ml,part=KO,skip -->
 ```ocaml
+let k = x = 1
 ```

test/bin/mdx-test/expect/parts-begin-end/test-case.md.expected

@@ -112,4 +112,13 @@ let () =
 ```
 
 ```ocaml skip,file=parts-begin-end.ml,part=toto
+let x = 34
+let f = 42.3
+let s = "toto"
+let fn x u = u x
+
+let () =
+  print_int x;
+  print_float f
+;;
 ```