From f737c5d3410e88524d18e26c633c89e2d495832a Mon Sep 17 00:00:00 2001
From: Patrick Ohly <patrick.ohly@intel.com>
Date: Mon, 26 Sep 2022 14:45:33 +0200
Subject: [PATCH] update-vendor.sh: handle empty staging repo

A staging repo which just got created with only the doc.go file in it won't
have any dependencies yet, which caused the script to fail because the
dependency files didn't get created:

    +++ [0926 14:33:22] go.mod: tidying
    cat: /tmp/update-vendor.1VTv/group_replace.ZbIT/go.mod.require_direct.tmp: No such file or directory
    !!! [0926 14:33:23] Call tree:
    !!! [0926 14:33:23]  1: hack/update-vendor.sh:354 group_directives(...)
---
 hack/update-vendor.sh | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/hack/update-vendor.sh b/hack/update-vendor.sh
index 0f0fe47af77..5b35ef7cfb1 100755
--- a/hack/update-vendor.sh
+++ b/hack/update-vendor.sh
@@ -114,6 +114,17 @@ function ensure_require_replace_directives_for_all_dependencies() {
       | xargs -L 100 go mod edit -fmt
 }
 
+function print_go_mod_section() {
+  local directive="$1"
+  local file="$2"
+
+  if [ -s "${file}" ]; then
+      echo "${directive} ("
+      cat "$file"
+      echo ")"
+  fi
+}
+
 function group_directives() {
   local local_tmp_dir
   local_tmp_dir=$(mktemp -d "${TMP_DIR}/group_replace.XXXX")
@@ -146,15 +157,9 @@ function group_directives() {
   " < go.mod
   {
     cat "${go_mod_other}";
-    echo "require (";
-    cat "${go_mod_require_direct}";
-    echo ")";
-    echo "require (";
-    cat "${go_mod_require_indirect}";
-    echo ")";
-    echo "replace (";
-    cat "${go_mod_replace}";
-    echo ")";
+    print_go_mod_section "require" "${go_mod_require_direct}"
+    print_go_mod_section "require" "${go_mod_require_indirect}"
+    print_go_mod_section "replace" "${go_mod_replace}"
   } > go.mod
 
   go mod edit -fmt