Don't return snippets to clients that don't support snippets

CHANGELOG.md

@@ -5,6 +5,7 @@ Meta:
 
 Bug Fixes:
 - Fix `textDocument/documentSymbol` on a non-fully initialized server (thanks [Jason Axelson](https://github.com/axelson)) [#173](https://github.com/elixir-lsp/elixir-ls/pull/173)
+- Don't return snippets to clients that don't declare `snippetSupport` for completions (thanks [Jason Axelson](https://github.com/axelson)) [#173](https://github.com/elixir-lsp/elixir-ls/pull/177)
 
 ### v0.3.2: 28 Mar 2020
 

apps/language_server/lib/language_server/providers/completion.ex

@@ -588,33 +588,37 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
   end
 
   defp items_to_json(items, snippets_supported) do
+    items =
+      Enum.reject(items, fn item ->
+        !snippets_supported && snippet?(item)
+      end)
+
     for {item, idx} <- Enum.with_index(items) do
-      json = %{
-        "label" => item.label,
-        "kind" => completion_kind(item.kind),
-        "detail" => item.detail,
-        "documentation" => %{"value" => item.documentation, kind: "markdown"},
-        "filterText" => item.filter_text,
-        "sortText" => String.pad_leading(to_string(idx), 8, "0")
-      }
+      item_to_json(item, idx, snippets_supported)
+    end
+  end
 
-      json =
+  defp item_to_json(item, idx, snippets_supported) do
+    json = %{
+      "label" => item.label,
+      "kind" => completion_kind(item.kind),
+      "detail" => item.detail,
+      "documentation" => %{"value" => item.documentation, kind: "markdown"},
+      "filterText" => item.filter_text,
+      "sortText" => String.pad_leading(to_string(idx), 8, "0"),
+      "insertText" => item.insert_text,
+      "insertTextFormat" =>
         if snippets_supported do
-          Map.merge(json, %{
-            "insertText" => item.insert_text,
-            "insertTextFormat" => insert_text_format(:snippet)
-          })
+          insert_text_format(:snippet)
         else
-          regex = Regex.recompile!(~r/\$(\{.*\})|(\$\d+).*$/)
-          text = Regex.replace(regex, item.insert_text, "")
-
-          Map.merge(json, %{
-            "insertText" => text,
-            "insertTextFormat" => insert_text_format(:plain_text)
-          })
+          insert_text_format(:plain_text)
         end
+    }
 
-      for {k, v} <- json, not is_nil(v), into: %{}, do: {k, v}
-    end
+    for {k, v} <- json, not is_nil(v), into: %{}, do: {k, v}
+  end
+
+  defp snippet?(item) do
+    item.kind == :snippet || String.match?(item.insert_text, ~r/\$\d/)
   end
 end

apps/language_server/test/providers/completion_test.exs

@@ -56,6 +56,28 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
     end
   end
 
+  test "unless with snippets not supported does not return a completion" do
+    text = """
+    defmodule MyModule do
+      require Logger, as: LAlias
+
+      def dummy_function() do
+        unless
+        #     ^
+      end
+    end
+    """
+
+    {line, char} = {4, 10}
+    TestUtils.assert_has_cursor_char(text, line, char)
+
+    {:ok, %{"items" => items}} = Completion.completion(text, line, char, true)
+    assert length(items) == 1
+
+    {:ok, %{"items" => items}} = Completion.completion(text, line, char, false)
+    assert length(items) == 0
+  end
+
   test "provides completions for protocol functions" do
     text = """
     defimpl ElixirLS.LanguageServer.Fixtures.ExampleProtocol, for: MyModule do