Load .browserslistrc when using old @babel/core versions (#12934)

packages/babel-preset-env/package.json

@@ -90,6 +90,7 @@
   },
   "devDependencies": {
     "@babel/core": "workspace:*",
+    "@babel/core-7.12": "npm:@babel/core@7.12.9",
     "@babel/helper-plugin-test-runner": "workspace:*",
     "@babel/plugin-syntax-dynamic-import": "^7.8.3"
   }

packages/babel-preset-env/src/index.js

@@ -1,6 +1,6 @@
 //@flow
 
-import { SemVer } from "semver";
+import { SemVer, lt } from "semver";
 import { logPluginOrPolyfill } from "./debug";
 import getOptionSpecificExcludesFor from "./get-option-specific-excludes";
 import { removeUnnecessaryItems } from "./filter-items";
@@ -295,6 +295,10 @@ export default declare((api, opts) => {
   let targets = babelTargets;
 
   if (
+    // @babel/core < 7.13.0 doesn't load targets (api.targets() always
+    // returns {} thanks to @babel/helper-plugin-utils), so we always want
+    // to fallback to the old targets behavior in this case.
+    lt(api.version, "7.13.0") ||
     // If any browserslist-related option is specified, fallback to the old
     // behavior of not using the targets specified in the top-level options.
     opts.targets ||

packages/babel-preset-env/test/regressions.js

@@ -0,0 +1,22 @@
+import * as babel7_12 from "@babel/core";
+import env from "..";
+import path from "path";
+
+describe("#12880", () => {
+  it("read the .browserslistrc file when using @babel/core < 7.13.0", () => {
+    // The browserslistrc file contains "firefox 50".
+    // a ** b is supported starting from firefox 52;
+    // a => b is supported starting from firefox 45.
+    const out = babel7_12.transformSync("a ** b; a => b;", {
+      configFile: false,
+      presets: [[env, { modules: false }]],
+      filename: path.join(__dirname, "regressions", "input.js"),
+    });
+
+    expect(out.code).toMatchInlineSnapshot(`
+      "Math.pow(a, b);
+
+      a => b;"
+    `);
+  });
+});

packages/babel-preset-env/test/regressions/.browserslistrc

@@ -0,0 +1 @@
+firefox 50