Pre-parse inferconfig_home and project_root

Summary:
Parse the inferconfig_home and project_root options in a separate phase
before other options.  This enables using their values to e.g. find the
inferconfig file and process it prior to full option parsing.

Reviewed By: jvillard

Differential Revision: D3302143

fbshipit-source-id: a1f9175

infer/src/backend/CommandLineOption.ml

@@ -308,7 +308,7 @@ let prefix_before_rest args =
   prefix_before_rest_ [] args
 
 
-let parse env_var exe_usage =
+let parse ?(incomplete=false) env_var exe_usage =
   let curr_speclist = ref []
   and full_speclist = ref []
   in
@@ -368,11 +368,17 @@ let parse env_var exe_usage =
   let env_args = c_args @ env_args in
   (* end transitional support for INFERCLANG_ARGS *)
   let exe_name, env_cl_args = prepend_to_argv env_args in
-  Unix.putenv env_var (encode_argv_to_env (prefix_before_rest env_cl_args)) ;
+  let current = ref 0 in
-  (try
+  let rec parse_loop () =
-     Arg.parse_argv (Array.of_list (exe_name :: env_cl_args)) !curr_speclist !anon_fun usage_msg
+    try
+      Arg.parse_argv_dynamic ~current (Array.of_list (exe_name :: env_cl_args))
+        curr_speclist !anon_fun usage_msg
     with
+    | Arg.Bad _ when incomplete -> parse_loop ()
     | Arg.Bad usage_msg -> Pervasives.prerr_string usage_msg; exit 2
     | Arg.Help usage_msg -> Pervasives.print_string usage_msg; exit 0
-  );
+  in
+  parse_loop () ;
+  if not incomplete then
+    Unix.putenv env_var (encode_argv_to_env (prefix_before_rest env_cl_args)) ;
   curr_usage

infer/src/backend/CommandLineOption.mli

@@ -93,4 +93,4 @@ val mk_anon :
     Therefore arguments passed on the command line supercede those specified in the environment
     variable.  WARNING: If an argument appears both in the environment variable and on the command
     line, it will be interpreted twice. *)
-val parse : string -> (exe -> Arg.usage_msg) -> (int -> 'a)
+val parse : ?incomplete:bool -> string -> (exe -> Arg.usage_msg) -> (int -> 'a)

infer/src/backend/config.ml

@@ -191,6 +191,34 @@ let os_type = match Sys.os_type with
 
 (** Command Line options *)
 
+(* Declare the phase 1 options *)
+
+let inferconfig_home =
+  CLOpt.mk_string_opt ~deprecated:["inferconfig_home"] ~long:"inferconfig-home"
+    ~exes:CLOpt.[A] ~meta:"dir" "Path to the .inferconfig file"
+
+and project_root =
+  CLOpt.mk_string_opt ~deprecated:["project_root"] ~long:"project-root" ~short:"pr"
+    ?default:(if CLOpt.(current_exe = P) then Some (Sys.getcwd ()) else None)
+    ~f:filename_to_absolute
+    ~exes:CLOpt.[A;C;J;L;P] ~meta:"dir" "Specify the root directory of the project"
+
+(* Parse the phase 1 options, ignoring the rest *)
+
+let _ = CLOpt.parse ~incomplete:true "INFER_ARGS" (fun _ -> "")
+
+(* Define the values that depend on phase 1 options *)
+
+let inferconfig_home = !inferconfig_home
+and project_root = !project_root
+
+let inferconfig_path =
+  match inferconfig_home, project_root with
+  | Some dir, _ | _, Some dir -> Filename.concat dir inferconfig_file
+  | None, None -> inferconfig_file
+
+(* Proceed to declare and parse the remaining options *)
+
 (** The references representing the command line options are defined in a single
     simultaneous let...and...and... binding in order to allow the type-checker to catch
     uses of one reference in code for another. This avoids being sensitive to
@@ -391,10 +419,6 @@ and infer_cache =
     ~f:filename_to_absolute
     ~meta:"dir" "Select a directory to contain the infer cache"
 
-and inferconfig_home =
-  CLOpt.mk_string_opt ~deprecated:["inferconfig_home"] ~long:"inferconfig-home"
-    ~exes:CLOpt.[A] ~meta:"dir" "Path to the .inferconfig file"
-
 (** Set the timeout values in seconds and symops, computed as a multiple of the integer
     parameter *)
 and iterations =
@@ -529,12 +553,6 @@ and progress_bar =
   CLOpt.mk_bool ~deprecated_no:["no_progress_bar"] ~long:"progress-bar" ~short:"pb" ~default:true
     "Show a progress bar"
 
-and project_root =
-  CLOpt.mk_string_opt ~deprecated:["project_root"] ~long:"project-root" ~short:"pr"
-    ?default:(if CLOpt.(current_exe = P) then Some (Sys.getcwd ()) else None)
-    ~f:filename_to_absolute
-    ~exes:CLOpt.[A;C;J;L;P] ~meta:"dir" "Specify the root directory of the project"
-
 (** command line flag: if true, do not print the spec to standard output *)
 and quiet =
   CLOpt.mk_bool ~long:"quiet" ~short:"q"
@@ -994,7 +1012,6 @@ and print_types = !print_types
 and print_using_diff = !print_using_diff
 and procs_csv = !procs_csv
 and procs_xml = !procs_xml
-and project_root = !project_root
 and quiet = !quiet
 and reactive_mode = !reactive
 and report = !report
@@ -1029,10 +1046,6 @@ and xml_specs = !xml_specs
 and zip_libraries = !zip_libraries
 
 let inferconfig_json =
-  let inferconfig_path =
-    match !inferconfig_home, project_root with
-    | Some dir, _ | _, Some dir -> Filename.concat dir inferconfig_file
-    | None, None -> inferconfig_file in
   lazy (
     match read_optional_json_file inferconfig_path with
     | Ok json -> json