Create binstubs for executables when activating a package.

sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_test.dart

Index: sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_test.dart b/sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..7fc058947952041b6cd3fdc9b6cb0c27e0e049d0
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_test.dart
@@ -0,0 +1,46 @@
+import 'package:scheduled_test/scheduled_stream.dart';
+import 'package:scheduled_test/scheduled_test.dart';
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration("does not overwrite an existing binstub", () {
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "executables": {
+          "foo": "foo",
+          "collide1": "foo",
+          "collide2": "foo"
+        }
+      }),
+          d.dir("bin", [d.file("foo.dart", "main() => print('ok');")])]).create();
+    d.dir("bar", [d.pubspec({
+        "name": "bar",
+        "executables": {
+          "bar": "bar",
+          "collide1": "bar",
+          "collide2": "bar"
+        }
+      }),
+          d.dir("bin", [d.file("bar.dart", "main() => print('ok');")])]).create();
+    schedulePub(args: ["global", "activate", "-spath", "../foo"]);
+    var pub = startPub(args: ["global", "activate", "-spath", "../bar"]);
+    pub.stdout.expect(consumeThrough("Installed executable bar."));
+    pub.stderr.expect("Executable collide1 was already installed from foo.");
+    pub.stderr.expect("Executable collide2 was already installed from foo.");
+    pub.stderr.expect(
+        "Deactivate the other package(s) or activate bar using "
+            "--overwrite-executables.");
+    pub.shouldExit();
+    d.dir(
+        cachePath,
+        [
+            d.dir(
+                "bin",
+                [
+                    d.matcherFile("foo", contains("foo:foo")),
+                    d.matcherFile("bar", contains("bar:bar")),
+                    d.matcherFile("collide1", contains("foo:foo")),
+                    d.matcherFile("collide2", contains("foo:foo"))])]).validate();
+  });
+}