cram: allow customizing the shell

doc/changes/added/13083.md

@@ -0,0 +1,2 @@
+- Add a `shell` field to the cram stanza. This field allows customizing the
+  shell to be `bash` rather than `sh` (#13083, @haochenx)

doc/reference/dune/cram.rst

@@ -129,3 +129,10 @@ Cram
       in this field. The order of evaluation for these scripts is deterministic
       but is left undefined, so it is not recommended that these scripts have
       side effects.
+
+   .. describe:: (shell <sh|bash>)
+
+      .. versionadded:: 3.22
+
+      Determines the shell executable to use to execute the cram script. By
+      default, cram scripts will execute with ``sh``.

src/dune_rules/cram/cram_exec.ml

@@ -432,14 +432,30 @@ let make_temp_dir ~script =
   temp_dir
 ;;
 
-let run_cram_test env ~src ~script ~cram_stanzas ~temp_dir ~cwd ~timeout ~setup_scripts =
+let run_cram_test
+      env
+      ~src
+      ~script
+      ~cram_stanzas
+      ~temp_dir
+      ~cwd
+      ~timeout
+      ~setup_scripts
+      (shell : Cram_stanza.Shell.t)
+  =
   let open Fiber.O in
   let* sh_script = create_sh_script cram_stanzas ~temp_dir ~setup_scripts in
   let env = make_run_env env ~temp_dir ~cwd in
   let open Fiber.O in
   let sh =
     let path = Env_path.path Env.initial in
-    match Bin.which ~path "sh" with
+    match
+      Bin.which
+        ~path
+        (match shell with
+         | Sh -> "sh"
+         | Bash -> "bash")
+    with
     | Some sh -> sh
     | None ->
       User_error.raise [ Pp.text "CRAM test aborted, \"sh\" can not be found in PATH" ]
@@ -509,14 +525,24 @@ let run_produce_correction
       ~script
       ~timeout
       ~setup_scripts
+      shell
       lexbuf
   =
   let temp_dir = make_temp_dir ~script in
   let cram_stanzas = cram_stanzas lexbuf ~conflict_markers |> List.map ~f:snd in
   let cwd = Path.parent_exn script in
   let env = make_run_env env ~temp_dir ~cwd in
   let open Fiber.O in
-  run_cram_test env ~src ~script ~cram_stanzas ~temp_dir ~cwd ~timeout ~setup_scripts
+  run_cram_test
+    env
+    ~src
+    ~script
+    ~cram_stanzas
+    ~temp_dir
+    ~cwd
+    ~timeout
+    ~setup_scripts
+    shell
   >>| compose_cram_output
 ;;
 
@@ -538,6 +564,7 @@ let run_and_produce_output
       ~dst
       ~timeout
       ~setup_scripts
+      shell
   =
   let script_contents = Io.read_file ~binary:false script in
   let lexbuf = Lexbuf.from_string script_contents ~fname:(Path.to_string script) in
@@ -548,7 +575,16 @@ let run_and_produce_output
   let env = make_run_env env ~temp_dir ~cwd in
   let open Fiber.O in
   let+ commands =
-    run_cram_test env ~src ~script ~cram_stanzas ~temp_dir ~cwd ~timeout ~setup_scripts
+    run_cram_test
+      env
+      ~src
+      ~script
+      ~cram_stanzas
+      ~temp_dir
+      ~cwd
+      ~timeout
+      ~setup_scripts
+      shell
     >>| List.filter_map ~f:(function
       | Cram_lexer.Command c -> Some c
       | Comment _ -> None)
@@ -567,12 +603,17 @@ module Run = struct
       ; output : 'target
       ; timeout : (Loc.t * Time.Span.t) option
       ; setup_scripts : 'path list
+      ; shell : Cram_stanza.Shell.t
       }
 
     let name = "cram-run"
-    let version = 3
+    let version = 4
 
-    let bimap ({ src = _; dir; script; output; timeout; setup_scripts } as t) f g =
+    let bimap
+          ({ src = _; dir; script; output; timeout; setup_scripts; shell = _ } as t)
+          f
+          g
+      =
       { t with
         dir = f dir
       ; script = f script
@@ -584,7 +625,7 @@ module Run = struct
 
     let is_useful_to ~memoize:_ = true
 
-    let encode { src = _; dir; script; output; timeout; setup_scripts } path target
+    let encode { src = _; dir; script; output; timeout; shell; setup_scripts } path target
       : Sexp.t
       =
       List
@@ -595,11 +636,12 @@ module Run = struct
             option float (Option.map ~f:(fun (_, time) -> Time.Span.to_secs time) timeout))
           |> Dune_sexp.to_sexp
         ; List (List.map ~f:path setup_scripts)
+        ; Atom (Cram_stanza.Shell.to_string shell)
         ]
     ;;
 
     let action
-          { src; dir; script; output; timeout; setup_scripts }
+          { src; dir; script; output; timeout; setup_scripts; shell }
           ~ectx:_
           ~(eenv : Action.env)
       =
@@ -612,14 +654,15 @@ module Run = struct
         ~dst:output
         ~timeout
         ~setup_scripts
+        shell
     ;;
   end
 
   include Action_ext.Make (Spec)
 end
 
-let run ~src ~dir ~script ~output ~timeout ~setup_scripts =
-  Run.action { src; dir; script; output; timeout; setup_scripts }
+let run ~src ~dir ~script ~output ~timeout ~setup_scripts shell =
+  Run.action { src; dir; script; output; timeout; setup_scripts; shell }
 ;;
 
 module Make_script = struct
@@ -743,7 +786,8 @@ module Action = struct
              ~env:eenv.env
              ~script
              ~timeout:None
-             ~setup_scripts:[])
+             ~setup_scripts:[]
+             Sh)
     ;;
   end
 

src/dune_rules/cram/cram_exec.mli

@@ -15,6 +15,7 @@ val run
   -> output:Path.Build.t
   -> timeout:(Loc.t * Time.Span.t) option
   -> setup_scripts:Path.t list
+  -> Cram_stanza.Shell.t
   -> Action.t
 
 (** Produces a diff if [src] needs to be updated *)

src/dune_rules/cram/cram_rules.ml

@@ -14,6 +14,7 @@ module Spec = struct
     ; timeout : (Loc.t * Time.Span.t) option
     ; conflict_markers : Cram_stanza.Conflict_markers.t
     ; setup_scripts : Path.t list
+    ; shell : Cram_stanza.Shell.t
     }
 
   let make_empty ~test_name_alias =
@@ -28,6 +29,7 @@ module Spec = struct
     ; timeout = None
     ; conflict_markers = Ignore
     ; setup_scripts = []
+    ; shell = Sh
     }
   ;;
 end
@@ -64,6 +66,7 @@ let test_rule
        ; timeout
        ; conflict_markers
        ; setup_scripts
+       ; shell
        } :
         Spec.t)
       (test : (Cram_test.t, error) result)
@@ -151,6 +154,7 @@ let test_rule
             ~output
             ~timeout
             ~setup_scripts
+            shell
           |> Action.Full.make ~locks ~sandbox)
          |> Action_builder.with_file_targets ~file_targets:[ output ]
          |> Super_context.add_rule sctx ~dir ~loc
@@ -302,6 +306,7 @@ let rules ~sctx ~dir tests =
               let conflict_markers =
                 Option.value ~default:acc.conflict_markers stanza.conflict_markers
               in
+              let shell = Option.value ~default:acc.shell stanza.shell in
               let setup_scripts =
                 let more_current_scripts =
                   List.map stanza.setup_scripts ~f:(fun (_loc, script) ->
@@ -328,6 +333,7 @@ let rules ~sctx ~dir tests =
                 ; timeout
                 ; conflict_markers
                 ; setup_scripts
+                ; shell
                 } ))
       in
       let extra_aliases =

src/dune_rules/cram/cram_stanza.ml

@@ -34,6 +34,21 @@ module Conflict_markers = struct
   let decode = enum (List.map all ~f:(fun x -> to_string x, x))
 end
 
+module Shell = struct
+  type t =
+    | Sh
+    | Bash
+
+  let all = [ "sh", Sh; "bash", Bash ]
+
+  let to_string =
+    let all = List.rev_map all ~f:Tuple.T2.swap in
+    fun x -> Option.value_exn (List.assoc all x)
+  ;;
+
+  let decode = enum all
+end
+
 type t =
   { loc : Loc.t
   ; applies_to : applies_to
@@ -46,6 +61,7 @@ type t =
   ; runtest_alias : (Loc.t * bool) option
   ; timeout : (Loc.t * Time.Span.t) option
   ; setup_scripts : (Loc.t * string) list
+  ; shell : Shell.t option
   }
 
 include Stanza.Make (struct
@@ -108,6 +124,8 @@ let decode =
            (Dune_lang.Syntax.since Stanza.syntax (3, 21) >>> repeat (located string))
        in
        Option.value scripts ~default:[]
+     and+ shell =
+       field_o "shell" (Dune_lang.Syntax.since Stanza.syntax (3, 22) >>> Shell.decode)
      in
      { loc
      ; alias
@@ -120,5 +138,6 @@ let decode =
      ; timeout
      ; conflict_markers
      ; setup_scripts
+     ; shell
      })
 ;;

src/dune_rules/cram/cram_stanza.mli

@@ -4,6 +4,14 @@ type applies_to =
   | Whole_subtree
   | Files_matching_in_this_dir of Predicate_lang.Glob.t
 
+module Shell : sig
+  type t =
+    | Sh
+    | Bash
+
+  val to_string : t -> string
+end
+
 module Conflict_markers : sig
   type t =
     | Error
@@ -24,6 +32,7 @@ type t =
   ; runtest_alias : (Loc.t * bool) option
   ; timeout : (Loc.t * Time.Span.t) option
   ; setup_scripts : (Loc.t * string) list
+  ; shell : Shell.t option
   }
 
 val decode : t Dune_lang.Decoder.t

test/blackbox-tests/test-cases/cram/bash-shell.t

@@ -0,0 +1,32 @@
+Demonstrate the shell field in the cram stanza
+
+  $ cat > dune-project <<EOF
+  > (lang dune 3.22)
+  > EOF
+
+  $ printShell() {
+  > dune trace cat | jq '.[] | select(.cat == "process" and (.args.categories | index("cram"))) | .args | .prog | split("/") | last'
+  > }
+
+  $ cat >foo.t <<'EOF'
+  >   $ echo foo
+  > EOF
+
+  $ dune runtest foo.t
+  File "foo.t", line 1, characters 0-0:
+  Error: Files _build/default/foo.t and _build/default/foo.t.corrected differ.
+  [1]
+  $ printShell
+  "sh"
+
+  $ cat > dune <<EOF
+  > (cram
+  >  (shell bash))
+  > EOF
+
+  $ dune runtest foo.t
+  File "foo.t", line 1, characters 0-0:
+  Error: Files _build/default/foo.t and _build/default/foo.t.corrected differ.
+  [1]
+  $ printShell
+  "bash"