[subcommands] support subcommands without leading --

Summary: `infer diff ...` works now.

Reviewed By: jberdine

Differential Revision: D4921062

fbshipit-source-id: a8a37c2

infer/src/base/CommandLineOption.ml

@@ -340,14 +340,9 @@ let curr_speclist : (Arg.key * Arg.spec * Arg.doc) list ref = ref []
 
 let unknown_args_action = ref `Reject
 
+let subcommand_actions = ref []
+
 let rev_anon_args = ref []
-let anon_fun arg = match !unknown_args_action with
-  | `Skip ->
-      ()
-  | `Add ->
-      rev_anon_args := arg::!rev_anon_args
-  | `Reject ->
-      raise (Arg.Bad ("unexpected anonymous argument: " ^ arg))
 
 (* keep track of the final parse action to drive the remainder of the program *)
 let final_parse_action = ref (Infer Driver)
@@ -698,6 +693,20 @@ let select_parse_action ~usage ?parse_all action =
   final_parse_action := action;
   usage
 
+let anon_fun arg =
+  match List.Assoc.find !subcommand_actions ~equal:String.equal arg with
+  | Some switch ->
+      switch ()
+  | None ->
+      match !unknown_args_action with
+      | `Skip ->
+          ()
+      | `Add ->
+          rev_anon_args := arg::!rev_anon_args
+      | `Reject ->
+          raise (Arg.Bad ("unexpected anonymous argument: " ^ arg))
+
+
 let mk_rest_actions ?(parse_mode=Infer []) doc ~usage decode_action =
   let rest = ref [] in
   let spec = String (fun arg ->
@@ -710,15 +719,19 @@ let mk_rest_actions ?(parse_mode=Infer []) doc ~usage decode_action =
   rest
 
 let mk_switch_parse_action
-    parse_action ~usage ?(deprecated=[]) ~long ?short ?parse_mode ?(meta="") doc =
+    parse_action ~usage ?(deprecated=[]) ~long ?(name=long) ?parse_mode ?(meta="") doc =
   let switch () =
     select_parse_action ~usage parse_action |> ignore in
   ignore(
-    mk ~deprecated ~long ?short ~default:() ?parse_mode ~meta doc
+    mk ~deprecated ~long ~default:() ?parse_mode ~meta doc
       ~default_to_string:(fun () -> "")
       ~decode_json:(string_json_decoder ~long)
       ~mk_setter:(fun _ _ -> switch ())
-      ~mk_spec:(fun _ -> Unit switch))
+      ~mk_spec:(fun _ -> Unit switch));
+  let add_action opt =
+    let sub = (opt, switch) in
+    subcommand_actions := sub::!subcommand_actions in
+  add_action name
 
 let decode_inferconfig_to_argv path =
   let json = match Utils.read_json_file path with

infer/src/base/CommandLineOption.mli

@@ -144,9 +144,11 @@ val mk_rest_actions :
   -> string list ref
 
 
-(** when the option is found on the command line, the current parse action is discarded and the
-    following arguments are parsed using [parse_action] *)
-val mk_switch_parse_action : parse_action -> usage:string -> unit t
+(** When the option is found on the command line, either as [--long] or [name], the current parse
+    action is discarded and the following arguments are parsed using [parse_action]. [name] defaults
+    to [long]. *)
+val mk_switch_parse_action : parse_action -> usage:string -> ?deprecated:string list ->
+  long:string -> ?name:string -> ?parse_mode:section list parse -> ?meta:string -> string -> unit
 
 (** environment variable use to pass arguments from parent to child processes *)
 val args_env_var : string

infer/src/base/Config.ml

@@ -402,8 +402,9 @@ let exe_usage = match current_exe with
 let anon_args = CLOpt.mk_anon ()
 
 and () =
-  CLOpt.mk_switch_parse_action CLOpt.Differential ~usage:"infer --diff [options]"
-    ~long:"diff" "[experimental] compute differential report"
+  CLOpt.mk_switch_parse_action CLOpt.Differential ~usage:"infer reportdiff [options]"
+    ~deprecated:["-diff"] ~long:"reportdiff"
+    "difference (preexisting/introduced/fixed) between two infer reports"
 
 and abs_struct =
   CLOpt.mk_int ~deprecated:["absstruct"] ~long:"abs-struct" ~default:1

infer/tests/differential.make

@@ -32,7 +32,7 @@ analyze: $(CURRENT_REPORT) $(PREVIOUS_REPORT)
 
 $(DIFFERENTIAL_REPORT): $(CURRENT_REPORT) $(PREVIOUS_REPORT)
 	$(QUIET)$(call silent_on_success,Computing results difference in $(TEST_REL_DIR),\
-	  $(INFER_BIN) -o $(INFER_OUT) --project-root $(CURDIR) --diff \
+	  $(INFER_BIN) -o $(INFER_OUT) --project-root $(CURDIR) reportdiff \
 		--report-current $(CURRENT_REPORT) --report-previous $(PREVIOUS_REPORT) \
 		$(DIFFERENTIAL_ARGS))