From e9a7054ff11a520e3b8aceb76a3ba44bb8da4c94 Mon Sep 17 00:00:00 2001
From: Moises Vega <moises.vega@gmail.com>
Date: Wed, 23 Feb 2022 11:09:34 -0800
Subject: [PATCH] Use merge_all() in emit_archive. (#3068)

---
 go/private/actions/archive.bzl | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/go/private/actions/archive.bzl b/go/private/actions/archive.bzl
index f8f6b7449b..ff99a8e8a5 100644
--- a/go/private/actions/archive.bzl
+++ b/go/private/actions/archive.bzl
@@ -65,10 +65,26 @@ def emit_archive(go, source = None, _recompile_suffix = ""):
     direct = [get_archive(dep) for dep in source.deps]
     runfiles = source.runfiles
     data_files = runfiles.files
-    for a in direct:
-        runfiles = runfiles.merge(a.runfiles)
-        if a.source.mode != go.mode:
-            fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
+
+    # After bazel version 5.0.0, skylark introduced a new API called merge_all().
+    # There is a recommendation in the release notes to use merge_all() if we hit
+    # the depth limit because of using merge() in a loop; we saw some repositories
+    # hitting this issue after upgrading to 5.0.0. To keep it backward compatible,
+    # we will fall back to the old logic if the array doesn't have merge_all().
+    # TODO: remove this check after the MINIMUM_BAZEL_VERSION becomes >= 5.0.0
+    # https://blog.bazel.build/2022/01/19/bazel-5.0.html#starlark-build-language
+    if hasattr(runfiles, "merge_all"):
+        files = []
+        for a in direct:
+            files.append(a.runfiles)
+            if a.source.mode != go.mode:
+                fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
+        runfiles.merge_all(files)
+    else:
+        for a in direct:
+            runfiles = runfiles.merge(a.runfiles)
+            if a.source.mode != go.mode:
+                fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
 
     importmap = "main" if source.library.is_main else source.library.importmap
     importpath, _ = effective_importpath_pkgpath(source.library)