Remove deprecated folder mapping

Node v16 deprecated the use of trailing "/" to define subpath folder
mappings in the "exports" field of package.json.

The recommendation is to explicitly list all our exports. We already do
that for all our public modules. I believe the only reason we have a
wildcard pattern is because our package.json files are also used at
build time (by Rollup) to resolve internal source modules that don't
appear in the final npm artifact.

Changing trailing "/" to "/*" fixes the warnings. See
https://nodejs.org/api/packages.html#subpath-patterns for more info.

Since the wildcard pattern only exists so our build script has access to
internal at build time, I've scoped the wildcard to "/src*". Because our
public modules are located outside the "src" directory, this means deep
imports of our modules will no longer work: only packages that are
listed in the "exports" field.

The only two affected packages are react-dom and react. We need to be
sure that all our public modules are still reachable. I audited the
exports by comparing the entries to the "files" field in package.json,
which represents a complete list of the files that are included in the
final release artifact.

At some point, we should add an e2e packaging test to prevent
regressions; for now, we should have decent coverage because in CI we
run our Jest test suite against the release artifacts.

Author: acdlite

packages/react-dom/package.json

@@ -48,8 +48,11 @@
     },
     "./profiling": "./profiling.js",
     "./test-utils": "./test-utils.js",
-    "./package.json": "./package.json",
-    "./": "./"
+    "./unstable_testing": "./unstable_testing.js",
+    "./testing": "./testing.js",
+    "./umd/*": "./umd/*",
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
   },
   "browser": {
     "./server.js": "./server.browser.js"

packages/react-server-dom-webpack/package.json

@@ -36,6 +36,7 @@
     "./writer.browser.server": "./writer.browser.server.js",
     "./node-loader": "./esm/react-server-dom-webpack-node-loader.js",
     "./node-register": "./node-register.js",
+    "./src/*": "./src/*",
     "./package.json": "./package.json"
   },
   "main": "index.js",

packages/react/package.json

@@ -31,7 +31,9 @@
     "./package.json": "./package.json",
     "./jsx-runtime": "./jsx-runtime.js",
     "./jsx-dev-runtime": "./jsx-dev-runtime.js",
-    "./": "./"
+    "./umd/*": "./umd/*",
+    "./unstable-shared-subset": "./unstable-shared-subset.js"
+
   },
   "repository": {
     "type": "git",