Allow for under development feature flags

vscode/src/common.ts

@@ -80,6 +80,8 @@ export const SUPPORTED_LANGUAGE_IDS = ["ruby", "erb"];
 // A list of feature flags where the key is the name and the value is the rollout percentage.
 //
 // Note: names added here should also be added to the `rubyLsp.optedOutFeatureFlags` enum in the `package.json` file
+// Note 2: -1 is a special value used to indicate under development features. Those can only be enabled explicitly and
+// are not impacted by the user's choice of opting into all flags
 export const FEATURE_FLAGS = {
   tapiocaAddon: 0.5,
   launcher: 0.1,
@@ -127,12 +129,16 @@ export function featureEnabled(feature: keyof typeof FEATURE_FLAGS): boolean {
     return false;
   }
 
+  const percentage = FEATURE_FLAGS[feature];
+
   // If the user opted-in to all features, return true
-  if (flagConfiguration.all || flagConfiguration[feature]) {
+  if (
+    (flagConfiguration.all && percentage !== -1) ||
+    flagConfiguration[feature]
+  ) {
     return true;
   }
 
-  const percentage = FEATURE_FLAGS[feature];
   const machineId = vscode.env.machineId;
   // Create a digest of the concatenated machine ID and feature name, which will generate a unique hash for this
   // user-feature combination

vscode/src/test/suite/common.test.ts

@@ -110,4 +110,32 @@ suite("Common", () => {
     stub.restore();
     assert.strictEqual(result, true);
   });
+
+  test("only returns true if explicitly opting into under development flags", () => {
+    (FEATURE_FLAGS as any).fakeFeature = -1;
+
+    // With only `all` enabled
+    const firstStub = sandbox
+      .stub(vscode.workspace, "getConfiguration")
+      .returns({
+        get: () => {
+          return { all: true };
+        },
+      } as any);
+
+    firstStub.restore();
+    assert.strictEqual(featureEnabled("fakeFeature" as any), false);
+
+    // With fakeFeature enabled
+    const secondStub = sandbox
+      .stub(vscode.workspace, "getConfiguration")
+      .returns({
+        get: () => {
+          return { all: true, fakeFeature: true };
+        },
+      } as any);
+
+    assert.strictEqual(featureEnabled("fakeFeature" as any), true);
+    secondStub.restore();
+  });
 });