Update overlay repository and rules_go (#139)

* In overlay repository rules, resolve labels before downloading the
  repo. This is a backport of bazelbuild/rules_go#1349.
* Update io_bazel_rules_go to tip of master.
* Fix //internal/wspace:go_default_test, which was broken on macOS.

WORKSPACE

@@ -3,7 +3,7 @@ workspace(name = "bazel_gazelle")
 git_repository(
     name = "io_bazel_rules_go",
     remote = "https://github.com/bazelbuild/rules_go",
-    commit = "d36234e86678457e769ab62e597f90eef025bf8d",
+    commit = "3e6e9bbf8f9ed35f5956fba80dde9283e121a66c",
 )
 
 load("@io_bazel_rules_go//go:def.bzl", "go_rules_dependencies", "go_register_toolchains")

internal/overlay_repository.bzl

@@ -13,14 +13,14 @@
 # limitations under the License.
 
 def _http_archive_impl(ctx):
+  overlay = _resolve_overlay(ctx, ctx.attr.overlay)
   ctx.download_and_extract(
       url = ctx.attr.urls,
       sha256 = ctx.attr.sha256,
       type = ctx.attr.type,
       stripPrefix = ctx.attr.strip_prefix,
   )
-
-  _apply_overlay(ctx, ctx.attr.overlay)
+  _apply_overlay(ctx, overlay)
 
 http_archive = repository_rule(
     implementation = _http_archive_impl,
@@ -43,12 +43,14 @@ def _git_repository_impl(ctx):
   if ctx.attr.commit and ctx.attr.tag:
     fail("'commit' and 'tag' may not both be specified")
 
+  overlay = _resolve_overlay(ctx, ctx.attr.overlay)
+
   # TODO(jayconrod): sanitize inputs passed to git.
   revision = ctx.attr.commit if ctx.attr.commit else ctx.attr.tag
   _check_execute(ctx, ["git", "clone", "-n", ctx.attr.remote, "."], "failed to clone %s" % ctx.attr.remote)
   _check_execute(ctx, ["git", "checkout", revision], "failed to checkout revision %s in remote %s" % (revision, ctx.attr.remote))
 
-  _apply_overlay(ctx, ctx.attr.overlay)
+  _apply_overlay(ctx, overlay)
 
 git_repository = repository_rule(
     implementation = _git_repository_impl,
@@ -60,11 +62,23 @@ git_repository = repository_rule(
     },
 )
 
+def _resolve_overlay(ctx, overlay):
+  """Resolve overlay labels to paths.
+
+  This should be done before downloading the repository, since it may
+  trigger restarts.
+  """
+  return [(ctx.path(src_label), dst_rel) for src_label, dst_rel in overlay.items()]
+
 def _apply_overlay(ctx, overlay):
+  """Copies overlay files into the repository.
+
+  This should be done after downloading the repository, since it may replace
+  downloaded files.
+  """
   # TODO(jayconrod): sanitize destination paths.
-  for src_label, dst_rel in overlay.items():
-    src_path = ctx.path(src_label)
-    _check_execute(ctx, ["cp", src_path, dst_rel], "failed to copy file from %s" % src_label)
+  for src_path, dst_rel in overlay:
+    _check_execute(ctx, ["cp", src_path, dst_rel], "failed to copy file from %s" % src_path)
 
 def _check_execute(ctx, arguments, message):
   res = ctx.execute(arguments)

internal/wspace/finder_test.go

@@ -29,6 +29,10 @@ func TestFind(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmp)
+	tmp, err = filepath.EvalSymlinks(tmp) // on macOS, TEST_TEMPDIR is a symlink
+	if err != nil {
+		t.Fatal(err)
+	}
 	if parent, err := Find(tmp); err == nil {
 		t.Skipf("WORKSPACE visible in parent %q of tmp %q", parent, tmp)
 	}