add a configuration option for advertised LSP providers

apps/els_core/src/els_config.erl

@@ -58,7 +58,8 @@
     | indexing_enabled
     | compiler_telemetry_enabled
     | refactorerl
-    | edoc_custom_tags.
+    | edoc_custom_tags
+    | providers.
 
 -type path() :: file:filename().
 -type state() :: #{
@@ -79,7 +80,8 @@
     code_reload => map() | 'disabled',
     indexing_enabled => boolean(),
     compiler_telemetry_enabled => boolean(),
-    refactorerl => map() | 'notconfigured'
+    refactorerl => map() | 'notconfigured',
+    providers => map()
 }.
 
 %%==============================================================================
@@ -147,6 +149,7 @@ do_initialize(RootUri, Capabilities, InitOptions, {ConfigPath, Config}) ->
     IndexingEnabled = maps:get(<<"indexingEnabled">>, InitOptions, true),
 
     RefactorErl = maps:get("refactorerl", Config, notconfigured),
+    Providers = maps:get("providers", Config, #{}),
 
     %% Passed by the LSP client
     ok = set(root_uri, RootUri),
@@ -160,6 +163,7 @@ do_initialize(RootUri, Capabilities, InitOptions, {ConfigPath, Config}) ->
     ok = set(macros, Macros),
     ok = set(plt_path, DialyzerPltPath),
     ok = set(code_reload, CodeReload),
+    ok = set(providers, Providers),
     ?LOG_INFO("Config=~p", [Config]),
     ok = set(
         runtime,

apps/els_lsp/src/els_general_provider.erl

@@ -3,6 +3,8 @@
 -behaviour(els_provider).
 -export([
     is_enabled/0,
+    default_providers/0,
+    enabled_providers/0,
     handle_request/1
 ]).
 
@@ -44,6 +46,7 @@
 -type exit_request() :: {exit, exit_params()}.
 -type exit_params() :: #{status => atom()}.
 -type exit_result() :: null.
+-type provider_id() :: string().
 
 %%==============================================================================
 %% els_provider functions
@@ -111,10 +114,60 @@ handle_request({exit, #{status := Status}}) ->
 %% API
 %%==============================================================================
 
+%% @doc Give all available providers
+-spec available_providers() -> [provider_id()].
+available_providers() ->
+    [
+        "text-document-sync",
+        "hover",
+        "completion",
+        "signature-help",
+        "definition",
+        "references",
+        "document-highlight",
+        "document-symbol",
+        "workspace-symbol",
+        "code-action",
+        "document-formatting",
+        "document-range-formatting",
+        "document-on-type-formatting",
+        "folding-range",
+        "implementation",
+        "execute-command",
+        "code-lens",
+        "rename",
+        "call-hierarchy"
+    ].
+
+%% @doc Give the list of all providers enabled by default.
+-spec default_providers() -> [provider_id()].
+default_providers() ->
+    available_providers() --
+        [
+            "document-range-formatting",
+            %% NOTE: because erlang_ls does not send incremental document changes
+            %%       via `textDocument/didChange', this kind of formatting does not
+            %%       make sense.
+            "document-on-type-formatting",
+            %% Signature help is experimental.
+            "signature-help"
+        ].
+
+%% @doc Give the list of all providers enabled by the current configuration.
+-spec enabled_providers() -> [provider_id()].
+enabled_providers() ->
+    Config = els_config:get(providers),
+    Default = default_providers(),
+    Enabled = maps:get("enabled", Config, []),
+    Disabled = maps:get("disabled", Config, []),
+    lists:usort((Default ++ valid(Enabled)) -- valid(Disabled)).
+
+%% @doc Give the LSP server capabilities map for all capabilities enabled by
+%% the current configuration.
 -spec server_capabilities() -> server_capabilities().
 server_capabilities() ->
     {ok, Version} = application:get_key(?APP, vsn),
-    Capabilities =
+    AvailableCapabilities =
         #{
             textDocumentSync =>
                 els_text_synchronization_provider:options(),
@@ -159,18 +212,16 @@ server_capabilities() ->
             callHierarchyProvider =>
                 els_call_hierarchy_provider:is_enabled()
         },
-    ActiveCapabilities =
-        case els_signature_help_provider:is_enabled() of
-            %% This pattern can never match because is_enabled/0 is currently
-            %% hard-coded to `false'. When enabling signature help manually,
-            %% uncomment this branch.
-            %% true ->
-            %%     Capabilities;
-            false ->
-                maps:remove(signatureHelpProvider, Capabilities)
-        end,
+    EnabledProviders = enabled_providers(),
+    ConfiguredCapabilities =
+        maps:filter(
+            fun(Provider, _Config) ->
+                lists:member(provider_id(Provider), EnabledProviders)
+            end,
+            AvailableCapabilities
+        ),
     #{
-        capabilities => ActiveCapabilities,
+        capabilities => ConfiguredCapabilities,
         serverInfo =>
             #{
                 name => <<"Erlang LS">>,
@@ -213,3 +264,49 @@ dynamic_registration_options(<<"didChangeWatchedFiles">>) ->
             watchers => [#{globPattern => GlobPattern}]
         }
     }.
+
+-spec valid([any()]) -> [provider_id()].
+valid(ProviderIds) ->
+    {Valid, Invalid} = lists:partition(fun is_valid_provider_id/1, ProviderIds),
+    case Invalid of
+        [] ->
+            ok;
+        _ ->
+            Fmt = "Discarding invalid providers in config file: ~p",
+            Args = [Invalid],
+            Msg = lists:flatten(io_lib:format(Fmt, Args)),
+            ?LOG_WARNING(Msg),
+            els_server:send_notification(
+                <<"window/showMessage">>,
+                #{
+                    type => ?MESSAGE_TYPE_WARNING,
+                    message => els_utils:to_binary(Msg)
+                }
+            )
+    end,
+    Valid.
+
+-spec is_valid_provider_id(any()) -> boolean().
+is_valid_provider_id(ProviderId) ->
+    lists:member(ProviderId, available_providers()).
+
+-spec provider_id(atom()) -> provider_id().
+provider_id(textDocumentSync) -> "text-document-sync";
+provider_id(completionProvider) -> "completion";
+provider_id(hoverProvider) -> "hover";
+provider_id(signatureHelpProvider) -> "signature-help";
+provider_id(definitionProvider) -> "definition";
+provider_id(referencesProvider) -> "references";
+provider_id(documentHighlightProvider) -> "document-highlight";
+provider_id(documentSymbolProvider) -> "document-symbol";
+provider_id(workspaceSymbolProvider) -> "workspace-symbol";
+provider_id(codeActionProvider) -> "code-action";
+provider_id(documentFormattingProvider) -> "document-formatting";
+provider_id(documentRangeFormattingProvider) -> "document-range-formatting";
+provider_id(documentOnTypeFormattingProvider) -> "document-on-type-formatting";
+provider_id(foldingRangeProvider) -> "folding-range";
+provider_id(implementationProvider) -> "implementation";
+provider_id(executeCommandProvider) -> "execute-command";
+provider_id(codeLensProvider) -> "code-lens";
+provider_id(renameProvider) -> "rename";
+provider_id(callHierarchyProvider) -> "call-hierarchy".

apps/els_lsp/test/els_initialization_SUITE.erl

@@ -22,7 +22,10 @@
     initialize_diagnostics_invalid/1,
     initialize_lenses_default/1,
     initialize_lenses_custom/1,
-    initialize_lenses_invalid/1
+    initialize_lenses_invalid/1,
+    initialize_providers_default/1,
+    initialize_providers_custom/1,
+    initialize_providers_invalid/1
 ]).
 
 %%==============================================================================
@@ -210,3 +213,45 @@ initialize_lenses_invalid(Config) ->
     ],
     ?assertEqual(Expected, Result),
     ok.
+
+-spec initialize_providers_default(config()) -> ok.
+initialize_providers_default(Config) ->
+    RootUri = els_test_utils:root_uri(),
+    DataDir = ?config(data_dir, Config),
+    ConfigPath = filename:join(DataDir, "providers_default.config"),
+    InitOpts = #{<<"erlang">> => #{<<"config_path">> => ConfigPath}},
+    els_client:initialize(RootUri, InitOpts),
+    Result = els_general_provider:enabled_providers(),
+    Expected = lists:usort(els_general_provider:default_providers()),
+    ?assertEqual(Expected, Result),
+    #{capabilities := Capabilities} = els_general_provider:server_capabilities(),
+    ?assertEqual(true, maps:is_key(hoverProvider, Capabilities)),
+    ok.
+
+-spec initialize_providers_custom(config()) -> ok.
+initialize_providers_custom(Config) ->
+    RootUri = els_test_utils:root_uri(),
+    DataDir = ?config(data_dir, Config),
+    ConfigPath = filename:join(DataDir, "providers_custom.config"),
+    InitOpts = #{<<"erlang">> => #{<<"config_path">> => ConfigPath}},
+    els_client:initialize(RootUri, InitOpts),
+    EnabledProviders = els_general_provider:enabled_providers(),
+    ?assertEqual(false, lists:member("hover", EnabledProviders)),
+    ?assertEqual(true, lists:member("document-on-type-formatting", EnabledProviders)),
+    #{capabilities := Capabilities} = els_general_provider:server_capabilities(),
+    ?assertEqual(false, maps:is_key(hoverProvider, Capabilities)),
+    ok.
+
+-spec initialize_providers_invalid(config()) -> ok.
+initialize_providers_invalid(Config) ->
+    RootUri = els_test_utils:root_uri(),
+    DataDir = ?config(data_dir, Config),
+    ConfigPath = filename:join(DataDir, "providers_invalid.config"),
+    InitOpts = #{<<"erlang">> => #{<<"config_path">> => ConfigPath}},
+    els_client:initialize(RootUri, InitOpts),
+    Result = els_general_provider:enabled_providers(),
+    Expected = lists:usort(els_general_provider:default_providers()),
+    ?assertEqual(Expected, Result),
+    #{capabilities := Capabilities} = els_general_provider:server_capabilities(),
+    ?assertEqual(true, maps:is_key(hoverProvider, Capabilities)),
+    ok.

apps/els_lsp/test/els_initialization_SUITE_data/providers_custom.config

@@ -0,0 +1,5 @@
+providers:
+    enabled:
+        - document-on-type-formatting
+    disabled:
+        - hover

apps/els_lsp/test/els_initialization_SUITE_data/providers_invalid.config

@@ -0,0 +1,5 @@
+providers:
+  enabled:
+    - hover
+  disabled:
+    - ssignaturee-hhelpp # Typos intentional