[flow] Support directory-conditional `module.system.node.root_relativ…

…e_dirname`

Summary: Changelog: [feature] `module.system.node.root_relative_dirname` will allow conditional mapping like `module.system.node.root_relative_dirname='<PROJECT_ROOT>/foo' -> 'bar'`. Under such config, `import 'a'` will only be resolved to `<PROJECT_ROOT>/bar/a` if `import 'a'` is in a file in the `<PROJECT_ROOT>/foo` directory. This feature will be helpful if you want to combine two flow roots with different `module.system.node.root_relative_dirname` config.

Reviewed By: panagosg7

Differential Revision: D69466985

fbshipit-source-id: 11ae4cb230f8f3d98fbb39b1780e88284d16c804

src/commands/commandUtils.ml

@@ -1450,7 +1450,11 @@ let make_options
     opt_saved_state_verify = saved_state_options_flags.saved_state_verify;
     opt_node_resolver_allow_root_relative = FlowConfig.node_resolver_allow_root_relative flowconfig;
     opt_node_resolver_root_relative_dirnames =
-      FlowConfig.node_resolver_root_relative_dirnames flowconfig;
+      Base.List.map
+        (FlowConfig.node_resolver_root_relative_dirnames flowconfig)
+        ~f:(fun (applicable_dir_opt, dirname) ->
+          (Base.Option.map ~f:(Files.expand_project_root_token ~root) applicable_dir_opt, dirname)
+      );
     opt_include_suppressions = options_flags.include_suppressions;
     opt_distributed = options_flags.distributed;
     opt_use_mixed_in_catch_variables =

src/commands/config/flowConfig.ml

@@ -121,7 +121,7 @@ module Opts = struct
     node_package_export_conditions: string list;
     node_resolver_allow_root_relative: bool;
     node_resolver_dirnames: string list;
-    node_resolver_root_relative_dirnames: string list;
+    node_resolver_root_relative_dirnames: (string option * string) list;
     pattern_matching: bool option;
     react_custom_jsx_typing: bool;
     react_ref_as_prop: Options.ReactRefAsProp.t;
@@ -260,7 +260,7 @@ module Opts = struct
       node_package_export_conditions = [];
       node_resolver_allow_root_relative = false;
       node_resolver_dirnames = ["node_modules"];
-      node_resolver_root_relative_dirnames = [""];
+      node_resolver_root_relative_dirnames = [(None, "")];
       pattern_matching = None;
       react_custom_jsx_typing = false;
       react_ref_as_prop = Options.ReactRefAsProp.PartialSupport;
@@ -367,14 +367,23 @@ module Opts = struct
             )
     )
 
-  let optparse_mapping =
+  let mapping_regexp =
     let regexp_str = "^'\\([^']*\\)'[ \t]*->[ \t]*'\\([^']*\\)'$" in
-    let regexp = Str.regexp regexp_str in
-    fun str ->
-      if Str.string_match regexp str 0 then
-        Ok (Str.matched_group 1 str, Str.matched_group 2 str)
-      else
-        Error ("Expected a mapping of form: " ^ "'single-quoted-string' -> 'single-quoted-string'")
+    Str.regexp regexp_str
+
+  let optparse_mapping str =
+    if Str.string_match mapping_regexp str 0 then
+      Ok (Str.matched_group 1 str, Str.matched_group 2 str)
+    else
+      Error ("Expected a mapping of form: " ^ "'single-quoted-string' -> 'single-quoted-string'")
+
+  let optparse_conditional_mapping str =
+    if Str.string_match mapping_regexp str 0 then
+      Ok (Str.matched_group 1 str, Some (Str.matched_group 2 str))
+    else
+      match optparse_string str with
+      | Ok s -> Ok (s, None)
+      | Error e -> Error e
 
   let boolean = enum [("true", true); ("false", false)]
 
@@ -395,6 +404,12 @@ module Opts = struct
         fn v
     )
 
+  let conditional_mapping fn =
+    opt (fun str ->
+        let%bind v = optparse_conditional_mapping str in
+        fn v
+    )
+
   let optparse_json str =
     try Ok (Hh_json.json_of_string str) with
     | Hh_json.Syntax_error msg -> Error (spf "Failed to parse JSON: %s" msg)
@@ -883,7 +898,11 @@ module Opts = struct
     boolean (fun opts v -> Ok { opts with node_resolver_allow_root_relative = v })
 
   let node_resolver_root_relative_dirnames_parser =
-    string
+    conditional_mapping
+      (function
+        | (applicable_directory, Some root_relative_dirname) ->
+          Ok (Some applicable_directory, root_relative_dirname)
+        | (root_relative_dirname, None) -> Ok (None, root_relative_dirname))
       ~init:(fun opts -> { opts with node_resolver_root_relative_dirnames = [] })
       ~multiple:true
       (fun opts v ->

src/commands/config/flowConfig.mli

@@ -226,7 +226,7 @@ val node_resolver_dirnames : config -> string list
 
 val pattern_matching : config -> bool option
 
-val node_resolver_root_relative_dirnames : config -> string list
+val node_resolver_root_relative_dirnames : config -> (string option * string) list
 
 val react_custom_jsx_typing : config -> bool
 

src/common/options.ml

@@ -134,7 +134,7 @@ type t = {
   opt_node_main_fields: string list;
   opt_node_package_export_conditions: string list;
   opt_node_resolver_allow_root_relative: bool;
-  opt_node_resolver_root_relative_dirnames: string list;
+  opt_node_resolver_root_relative_dirnames: (string option * string) list;
   opt_profile: bool;
   opt_quiet: bool;
   opt_react_custom_jsx_typing: bool;

src/services/module/module_js.ml

@@ -518,24 +518,35 @@ module Node = struct
     if Options.node_resolver_allow_root_relative options then
       let dirnames = Options.node_resolver_root_relative_dirnames options in
       let root = Options.root options |> File_path.to_string in
-      let f dirname =
+      let f (applicable_dirname_opt, dirname) =
         let relative_to_directory =
           if dirname = "" then
             root
           else
             Files.normalize_path root dirname
         in
-        lazy
-          (resolve_relative
-             ~options
-             ~reader
-             ~phantom_acc
-             ~importing_file
-             ~relative_to_directory
-             import_specifier
-          )
+        let applicable =
+          Base.Option.value_map
+            applicable_dirname_opt
+            ~f:(fun prefix -> Files.is_prefix prefix (File_key.to_string importing_file))
+            ~default:true
+        in
+        if applicable then
+          Some
+            ( lazy
+              (resolve_relative
+                 ~options
+                 ~reader
+                 ~phantom_acc
+                 ~importing_file
+                 ~relative_to_directory
+                 import_specifier
+              )
+              )
+        else
+          None
       in
-      lazy_seq (Base.List.map ~f dirnames)
+      lazy_seq (Base.List.filter_map ~f dirnames)
     else
       None
 

tests/config_module_system_node_root_relative_dirnames/.flowconfig

@@ -4,3 +4,4 @@ module.system.node.allow_root_relative=true
 module.system.node.root_relative_dirname=first
 module.system.node.root_relative_dirname=second
 module.system.node.root_relative_dirname=./third
+module.system.node.root_relative_dirname='<PROJECT_ROOT>/only-here-can-we-use-root-relative-fourth' -> 'fourth'

tests/config_module_system_node_root_relative_dirnames/config_module_system_node_root_relative_dirnames.exp

@@ -176,5 +176,13 @@ References:
                              ^ [2]
 
 
+Error ----------------------------------------------------------------------------------------------------- test.js:46:8
 
-Found 11 errors
+Cannot resolve module `4`. [cannot-resolve-module]
+
+   46| import '4'; // error: not in only-here-can-we-use-root-relative-fourth
+              ^^^
+
+
+
+Found 12 errors

tests/config_module_system_node_root_relative_dirnames/only-here-can-we-use-root-relative-fourth/test.js

@@ -0,0 +1 @@
+import '4'; // ok, we are in only-here-can-we-use-root-relative-fourth

tests/config_module_system_node_root_relative_dirnames/test.js

@@ -42,3 +42,5 @@ import nonexistent from 'nonexistent'
 import sub_nonexistent from 'subdir/nonexistent'
 
 require('js_flow') as 4 // resolved, but number ~> 4 error
+
+import '4'; // error: not in only-here-can-we-use-root-relative-fourth