manual side effects flagging should override automatic analysis

sokra · sokra · commit 1e2634fdd8b5 · 2020-12-15T14:40:54.000+01:00
diff --git a/lib/NormalModule.js b/lib/NormalModule.js
@@ -868,8 +868,10 @@ class NormalModule extends Module {
 	 * @returns {ConnectionState} how this module should be connected to referencing modules when consumed for side-effects only
 	 */
 	getSideEffectsConnectionState(moduleGraph) {
-		if (this.factoryMeta !== undefined && this.factoryMeta.sideEffectFree)
-			return false;
+		if (this.factoryMeta !== undefined) {
+			if (this.factoryMeta.sideEffectFree) return false;
+			if (this.factoryMeta.sideEffectFree === false) return true;
+		}
 		if (this.buildMeta !== undefined && this.buildMeta.sideEffectFree) {
 			if (this._isEvaluatingSideEffects)
 				return ModuleGraphConnection.CIRCULAR_CONNECTION;
diff --git a/lib/optimize/SideEffectsFlagPlugin.js b/lib/optimize/SideEffectsFlagPlugin.js
@@ -82,16 +82,16 @@ class SideEffectsFlagPlugin {
 							resolveData.relativePath
 						) {
 							const sideEffects = resolveData.descriptionFileData.sideEffects;
-							const hasSideEffects = SideEffectsFlagPlugin.moduleHasSideEffects(
-								resolveData.relativePath,
-								sideEffects,
-								cache
-							);
-							if (!hasSideEffects) {
+							if (sideEffects !== undefined) {
 								if (module.factoryMeta === undefined) {
 									module.factoryMeta = {};
 								}
-								module.factoryMeta.sideEffectFree = true;
+								const hasSideEffects = SideEffectsFlagPlugin.moduleHasSideEffects(
+									resolveData.relativePath,
+									sideEffects,
+									cache
+								);
+								module.factoryMeta.sideEffectFree = !hasSideEffects;
 							}
 						}
 
@@ -101,15 +101,11 @@ class SideEffectsFlagPlugin {
 				normalModuleFactory.hooks.module.tap(
 					"SideEffectsFlagPlugin",
 					(module, data) => {
-						if (data.settings.sideEffects === false) {
+						if (typeof data.settings.sideEffects === "boolean") {
 							if (module.factoryMeta === undefined) {
 								module.factoryMeta = {};
 							}
-							module.factoryMeta.sideEffectFree = true;
-						} else if (data.settings.sideEffects === true) {
-							if (module.factoryMeta !== undefined) {
-								module.factoryMeta.sideEffectFree = false;
-							}
+							module.factoryMeta.sideEffectFree = !data.settings.sideEffects;
 						}
 						return module;
 					}
