[be] Improve feature flags setup

Updates `Environment` to store all feature flags on a single `config` object. We 
now also define an object with all the default config values, and use this to 
populate defaults for any missing values in the user-provided config.

compiler/packages/babel-plugin-react-forget/src/Entrypoint/Options.ts

@@ -7,7 +7,7 @@
 
 import * as t from "@babel/types";
 import { CompilerErrorDetailOptions } from "../CompilerError";
-import { EnvironmentConfig } from "../HIR/Environment";
+import { PartialEnvironmentConfig } from "../HIR/Environment";
 
 export type ExternalFunction = {
   /**
@@ -39,7 +39,7 @@ export type PanicThresholdOptions =
   | "NONE";
 
 export type PluginOptions = {
-  environment: EnvironmentConfig | null;
+  environment: PartialEnvironmentConfig | null;
 
   logger: Logger | null;
 

compiler/packages/babel-plugin-react-forget/src/Entrypoint/Pipeline.ts

@@ -17,7 +17,7 @@ import {
   lower,
   mergeConsecutiveBlocks,
 } from "../HIR";
-import { Environment, EnvironmentConfig } from "../HIR/Environment";
+import { Environment, PartialEnvironmentConfig } from "../HIR/Environment";
 import { findContextIdentifiers } from "../HIR/FindContextIdentifiers";
 import {
   analyseFunctions,
@@ -82,7 +82,7 @@ export function* run(
   func: NodePath<
     t.FunctionDeclaration | t.ArrowFunctionExpression | t.FunctionExpression
   >,
-  config?: EnvironmentConfig | null
+  config?: PartialEnvironmentConfig | null
 ): Generator<CompilerPipelineValue, CodegenFunction> {
   const contextIdentifiers = findContextIdentifiers(func);
   const env = new Environment(config ?? null, contextIdentifiers);
@@ -106,7 +106,7 @@ function* runWithEnvironment(
   pruneMaybeThrows(hir);
   yield log({ kind: "hir", name: "PruneMaybeThrows", value: hir });
 
-  if (env.inlineUseMemo) {
+  if (env.config.inlineUseMemo) {
     inlineUseMemo(hir);
     yield log({ kind: "hir", name: "RewriteUseMemo", value: hir });
   }
@@ -131,7 +131,7 @@ function* runWithEnvironment(
   inferTypes(hir);
   yield log({ kind: "hir", name: "InferTypes", value: hir });
 
-  if (env.validateHooksUsage) {
+  if (env.config.validateHooksUsage) {
     validateHooksUsage(hir);
     const conditionalHooksResult = validateUnconditionalHooks(hir).unwrap();
     yield log({
@@ -150,7 +150,7 @@ function* runWithEnvironment(
   inferReferenceEffects(hir);
   yield log({ kind: "hir", name: "InferReferenceEffects", value: hir });
 
-  if (env.validateFrozenLambdas) {
+  if (env.config.validateFrozenLambdas) {
     validateFrozenLambdas(hir);
   }
 
@@ -164,15 +164,15 @@ function* runWithEnvironment(
   inferMutableRanges(hir);
   yield log({ kind: "hir", name: "InferMutableRanges", value: hir });
 
-  if (env.assertValidMutableRanges) {
+  if (env.config.assertValidMutableRanges) {
     assertValidMutableRanges(hir);
   }
 
-  if (env.validateRefAccessDuringRender) {
+  if (env.config.validateRefAccessDuringRender) {
     validateNoRefAccessInRender(hir);
   }
 
-  if (env.validateNoSetStateInRender) {
+  if (env.config.validateNoSetStateInRender) {
     const noSetStateInRenderResult = validateNoSetStateInRender(hir).unwrap();
     yield log({
       kind: "debug",
@@ -222,7 +222,7 @@ function* runWithEnvironment(
     value: reactiveFunction,
   });
 
-  if (env.disableAllMemoization) {
+  if (env.config.disableAllMemoization) {
     pruneAllReactiveScopes(reactiveFunction);
     yield log({
       kind: "reactive",
@@ -259,8 +259,8 @@ function* runWithEnvironment(
     value: reactiveFunction,
   });
 
-  let memoizeJsxElements = env.memoizeJsxElements;
-  if (env.enableForest) {
+  let memoizeJsxElements = env.config.memoizeJsxElements;
+  if (env.config.enableForest) {
     memoizeJsxElements = false;
   }
   pruneNonEscapingScopes(reactiveFunction, { memoizeJsxElements });
@@ -284,7 +284,7 @@ function* runWithEnvironment(
     value: reactiveFunction,
   });
 
-  if (env.enableMergeConsecutiveScopes) {
+  if (env.config.enableMergeConsecutiveScopes) {
     mergeConsecutiveScopes(reactiveFunction);
     yield log({
       kind: "reactive",
@@ -293,7 +293,7 @@ function* runWithEnvironment(
     });
   }
 
-  if (env.enableForest) {
+  if (env.config.enableForest) {
     yield* lowerToForest(reactiveFunction);
   }
 
@@ -349,7 +349,7 @@ export function compileFn(
   func: NodePath<
     t.FunctionDeclaration | t.ArrowFunctionExpression | t.FunctionExpression
   >,
-  options?: Partial<EnvironmentConfig> | null
+  options?: Partial<PartialEnvironmentConfig> | null
 ): CodegenFunction {
   let generator = run(func, options);
   while (true) {

compiler/packages/babel-plugin-react-forget/src/HIR/BuildHIR.ts

@@ -1436,7 +1436,7 @@ function lowerExpression(
           elements.push({
             kind: "Hole",
           });
-          if (builder.environment.bailoutOnHoleyArrays) {
+          if (builder.environment.config.bailoutOnHoleyArrays) {
             builder.errors.push({
               reason: `(BuildHIR::lower) Fix babel holey array backward compatibility.`,
               severity: ErrorSeverity.Todo,

compiler/packages/babel-plugin-react-forget/src/HIR/Environment.ts

@@ -84,8 +84,9 @@ export type Hook = {
 // i.e.
 //   missing required shapes (BuiltInArray for [] and BuiltInObject for {})
 //   missing some recursive Object / Function shapeIds
-export type EnvironmentConfig = Partial<{
-  customHooks: Map<string, Hook>;
+
+export type CompleteEnvironmentConfig = {
+  customHooks: Map<string, Hook> | null;
 
   // 🌲
   enableForest: boolean;
@@ -243,42 +244,59 @@ export type EnvironmentConfig = Partial<{
    * https://github.com/babel/babel/pull/10917/files#diff-19b555d2f3904c206af406540d9df200b1e16befedb83ff39ebfcbd876f7fa8aL52-R56
    */
   bailoutOnHoleyArrays: boolean;
-}>;
+};
+
+const DEFAULT_ENVIRONMENT_CONFIG: CompleteEnvironmentConfig = {
+  customHooks: null,
+
+  enableTreatHooksAsFunctions: true,
+  memoizeJsxElements: true,
+
+  assertValidMutableRanges: false,
+  bailoutOnHoleyArrays: false,
+  disableAllMemoization: false,
+  enableAssumeHooksFollowRulesOfReact: false,
+  enableEmitFreeze: null,
+  enableForest: false,
+  enableFunctionCallSignatureOptimizations: false,
+  enableMergeConsecutiveScopes: false,
+  enableNoAliasOptimizations: false,
+  inlineUseMemo: false,
+
+  validateFrozenLambdas: false,
+  validateHooksUsage: false,
+  validateNoSetStateInRender: false,
+  validateRefAccessDuringRender: false,
+};
+
+export type PartialEnvironmentConfig = Partial<CompleteEnvironmentConfig>;
 
 export class Environment {
   #globals: GlobalRegistry;
   #shapes: ShapeRegistry;
   #nextIdentifer: number = 0;
   #nextBlock: number = 0;
-  validateHooksUsage: boolean;
-  validateRefAccessDuringRender: boolean;
-  validateFrozenLambdas: boolean;
-  validateNoSetStateInRender: boolean;
-  enableFunctionCallSignatureOptimizations: boolean;
-  enableAssumeHooksFollowRulesOfReact: boolean;
-  enableTreatHooksAsFunctions: boolean;
-  enableNoAliasOptimizations: boolean;
-  inlineUseMemo: boolean;
-  memoizeJsxElements: boolean;
-  disableAllMemoization: boolean;
-  enableEmitFreeze: ExternalFunction | null;
-  enableMergeConsecutiveScopes: boolean;
-  assertValidMutableRanges: boolean;
-  bailoutOnHoleyArrays: boolean;
-  enableForest: boolean;
+  config: CompleteEnvironmentConfig;
 
   #contextIdentifiers: Set<t.Identifier>;
   #hoistedIdentifiers: Set<t.Identifier>;
 
   constructor(
-    config: EnvironmentConfig | null,
+    partialConfig: PartialEnvironmentConfig | null,
     contextIdentifiers: Set<t.Identifier>
   ) {
     this.#shapes = new Map(DEFAULT_SHAPES);
+    const config: CompleteEnvironmentConfig = { ...DEFAULT_ENVIRONMENT_CONFIG };
+    for (const rawKey in DEFAULT_ENVIRONMENT_CONFIG) {
+      const key = rawKey as keyof CompleteEnvironmentConfig;
+      const value = partialConfig?.[key] ?? DEFAULT_ENVIRONMENT_CONFIG[key];
+      config[key] = value as any;
+    }
+    this.config = config;
 
-    if (config?.customHooks) {
+    if (this.config.customHooks != null && this.config.customHooks.size > 0) {
       this.#globals = new Map(DEFAULT_GLOBALS);
-      for (const [hookName, hook] of config.customHooks) {
+      for (const [hookName, hook] of this.config.customHooks) {
         CompilerError.invariant(!this.#globals.has(hookName), {
           reason: `[Globals] Found existing definition in global registry for custom hook ${hookName}`,
           description: null,
@@ -303,29 +321,6 @@ export class Environment {
     } else {
       this.#globals = DEFAULT_GLOBALS;
     }
-    this.validateHooksUsage = config?.validateHooksUsage ?? false;
-    this.validateRefAccessDuringRender =
-      config?.validateRefAccessDuringRender ?? false;
-    this.validateFrozenLambdas = config?.validateFrozenLambdas ?? false;
-    this.enableFunctionCallSignatureOptimizations =
-      config?.enableFunctionCallSignatureOptimizations ?? false;
-    this.enableNoAliasOptimizations =
-      config?.enableNoAliasOptimizations ?? false;
-    this.enableAssumeHooksFollowRulesOfReact =
-      config?.enableAssumeHooksFollowRulesOfReact ?? false;
-    this.enableTreatHooksAsFunctions =
-      config?.enableTreatHooksAsFunctions ?? true;
-    this.disableAllMemoization = config?.disableAllMemoization ?? false;
-    this.enableEmitFreeze = config?.enableEmitFreeze ?? null;
-    this.enableMergeConsecutiveScopes =
-      config?.enableMergeConsecutiveScopes ?? false;
-    this.assertValidMutableRanges = config?.assertValidMutableRanges ?? false;
-    this.validateNoSetStateInRender =
-      config?.validateNoSetStateInRender ?? false;
-    this.inlineUseMemo = config?.inlineUseMemo ?? false;
-    this.memoizeJsxElements = config?.memoizeJsxElements ?? true;
-    this.bailoutOnHoleyArrays = config?.bailoutOnHoleyArrays ?? false;
-    this.enableForest = config?.enableForest ?? false;
 
     this.#contextIdentifiers = contextIdentifiers;
     this.#hoistedIdentifiers = new Set();
@@ -412,7 +407,7 @@ export class Environment {
   }
 
   #getCustomHookType(): Global {
-    if (this.enableAssumeHooksFollowRulesOfReact) {
+    if (this.config.enableAssumeHooksFollowRulesOfReact) {
       return DefaultNonmutatingHook;
     } else {
       return DefaultMutatingHook;

compiler/packages/babel-plugin-react-forget/src/Inference/InferReferenceEffects.ts

@@ -747,7 +747,7 @@ function inferBlock(
           instrValue.callee.identifier.type
         );
         signature =
-          env.enableFunctionCallSignatureOptimizations ||
+          env.config.enableFunctionCallSignatureOptimizations ||
           signature?.hookKind != null
             ? signature
             : null;
@@ -755,7 +755,7 @@ function inferBlock(
         if (
           signature &&
           signature.hookKind != null &&
-          !env.enableTreatHooksAsFunctions
+          !env.config.enableTreatHooksAsFunctions
         ) {
           effectKind = signature.restParam;
           valueKind = signature.returnValueKind;

compiler/packages/babel-plugin-react-forget/src/ReactiveScopes/CodegenReactiveFunction.ts

@@ -184,12 +184,12 @@ function codegenBlock(cx: Context, block: ReactiveBlock): t.BlockStatement {
 }
 
 function wrapCacheDep(cx: Context, value: t.Expression): t.Expression {
-  if (cx.env.enableEmitFreeze != null) {
+  if (cx.env.config.enableEmitFreeze != null) {
     // The import declaration for emitFreeze is inserted in the Babel plugin
     return t.conditionalExpression(
       t.identifier("__DEV__"),
       t.callExpression(
-        t.identifier(cx.env.enableEmitFreeze.importSpecifierName),
+        t.identifier(cx.env.config.enableEmitFreeze.importSpecifierName),
         [value, t.stringLiteral(cx.fnName)]
       ),
       value
@@ -383,7 +383,7 @@ function codegenReactiveScope(
   scope: ReactiveScope,
   block: ReactiveBlock
 ): void {
-  if (cx.env.enableForest) {
+  if (cx.env.config.enableForest) {
     codegenSignalBlockForReactiveScope(cx, statements, scope, block);
   } else {
     codegenMemoBlockForReactiveScope(cx, statements, scope, block);

compiler/packages/babel-plugin-react-forget/src/ReactiveScopes/InferReactiveScopeVariables.ts

@@ -250,7 +250,7 @@ function mayAllocate(env: Environment, instruction: Instruction): boolean {
     }
     case "CallExpression":
     case "MethodCall": {
-      if (env.enableFunctionCallSignatureOptimizations) {
+      if (env.config.enableFunctionCallSignatureOptimizations) {
         return instruction.lvalue.identifier.type.kind !== "Primitive";
       }
       return true;

compiler/packages/babel-plugin-react-forget/src/ReactiveScopes/PruneNonEscapingScopes.ts

@@ -611,7 +611,7 @@ function computeMemoizationInputs(
       };
     }
     case "CallExpression": {
-      const signature = env.enableNoAliasOptimizations
+      const signature = env.config.enableNoAliasOptimizations
         ? getFunctionCallSignature(env, value.callee.identifier.type)
         : null;
       const operands = [...eachReactiveValueOperand(value)];
@@ -636,7 +636,7 @@ function computeMemoizationInputs(
       };
     }
     case "MethodCall": {
-      const signature = env.enableNoAliasOptimizations
+      const signature = env.config.enableNoAliasOptimizations
         ? getFunctionCallSignature(env, value.property.identifier.type)
         : null;
       const operands = [...eachReactiveValueOperand(value)];
@@ -808,7 +808,7 @@ class CollectDependenciesVisitor extends ReactiveFunctionVisitor<State> {
     } else if (instruction.value.kind === "CallExpression") {
       const callee = instruction.value.callee;
       if (getHookKind(state.env, callee.identifier) != null) {
-        const signature = this.env.enableNoAliasOptimizations
+        const signature = this.env.config.enableNoAliasOptimizations
           ? getFunctionCallSignature(
               this.env,
               instruction.value.callee.identifier.type