Set default configs for ignoring submodule diffs.

crup-runner.sh

 #!/bin/bash
 
 update_toplevel () {
   # Don't "pull" if checkout is not on a named branch
   if test "$2" = "pull" && ( ! git symbolic-ref HEAD >/dev/null 2>/dev/null ); then
     first_args="$1 fetch"
   else
     first_args="$1 $2"
   fi
   shift 2
@@ skipping 47 matching lines @@
     if [ -n "$submod_os" -a \
         "$submod_os" != "all" -a \
         "${submod_os/${target_os}/}" = "${submod_os}" ]; then
       update_policy=none
     else
       git submodule --quiet init "$1"
       update_policy=checkout
     fi
     git config "submodule.$1.update" $update_policy
   fi
+  ignore_policy=$(git config --get "submodule.$1.ignore")
+  if [ -z "$ignore_policy" ]; then
+    git config "submodule.$1.ignore" all
+  fi
   if [ "$update_policy" != "none" ]; then
     update_submodule_url "$1"
     echo "$solution/$1"
   fi
 }
 
 if [ -z "$*" ]; then
   exit 0
 fi
 set -o pipefail
 dir="$1"
 solution="${1%%/*}"
 cd "$solution" 1>/dev/null
 
 if [ "$solution" = "$1" ]; then
   # Skip git checkouts not managed by crup.
   if ! grep -q -s "The Chromium Authors" ".git/description"; then
     echo "Skipping unmanaged git directory $1" 1>&2
     exit 0
   fi
 
+  # Set default behavior to ignore diffs in submodule checkouts
+  diff_policy=$(git config --get "diff.ignoreSubmodules")
+  if [ -z "$diff_policy" ]; then
+    git config diff.ignoreSubmodules all
+  fi
+
+  # Don't "pull" if checkout is not on a named branch
   shift
   if test $# -ne 0; then
     update_toplevel "$@"
   fi
 
   set_target_os
 
   "$GIT_EXE" ls-files -s | grep ^160000 | awk '{print $4}' |
   while read submod; do
     process_submodule "$submod"
   done
   status=$?
 else
   submodule="${1#*/}"
   echo "[$solution] updating $submodule"
   "$GIT_EXE" submodule update --quiet "$submodule" |
   ( grep -v '^Skipping submodule' || true ) | sed "s|^|[$1] |g"
   status=$?
   if [ "$status" -ne "0" ]; then
     echo "[$solution] FAILED to update $submodule"
   fi
 fi
 exit $status