feat(webpack): auto fallback to commonjs via runtime detection

packages/webpack5/src/helpers/dependencies.ts

@@ -1,5 +1,6 @@
 import path from 'path';
 
+import { satisfies } from 'semver';
 import { getPackageJson, getProjectRootPath } from './project';
 
 // todo: memoize
@@ -67,3 +68,41 @@ export function getDependencyVersion(dependencyName: string): string | null {
 	}
 	return null;
 }
+
+/**
+ * Resolve a usable version string for checks (eg. semver.satisfies).
+ * Strategy:
+ *  - prefer installed package.json version (getDependencyVersion)
+ *  - fall back to declared version in project package.json (dependencies/devDependencies)
+ *  - if declared is a common dist-tag (alpha|beta|rc|next) return a 9.x prerelease
+ */
+export function getResolvedDependencyVersionForCheck(dependencyName: string, target: string): string | null {
+	// try installed
+	const installed = getDependencyVersion(dependencyName);
+	if (installed) {
+		return installed;
+	}
+
+	// try declared in project package.json
+	const pkg = getPackageJson();
+	const declared = (pkg.dependencies && pkg.dependencies[dependencyName]) || (pkg.devDependencies && pkg.devDependencies[dependencyName]);
+	if (!declared) {
+		return null;
+	}
+
+	// if declared already satisfies semver check, use it
+	try {
+		if (satisfies(declared, `>=${target}`)) {
+			return declared;
+		}
+	} catch (e) {
+		// ignore parse errors
+	}
+
+	// common dist-tags -> treat as prerelease of 9.x for the purpose of >=9 checks
+	if (/^(alpha|beta|rc|next)$/.test(String(declared))) {
+		return `${target}-0`;
+	}
+
+	return declared ?? null;
+}