Merge branch 'km/submodule-add-errmsg'

Improve error message generation for "git submodule add".

* km/submodule-add-errmsg:
  submodule add: show 'add --dry-run' stderr when aborting

git-submodule.sh

@@ -241,13 +241,15 @@ cmd_add()
 	    die "$(eval_gettext "'\$sm_path' does not have a commit checked out")"
 	fi
 
-	if test -z "$force" &&
-		! git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" > /dev/null 2>&1
+	if test -z "$force"
 	then
-		eval_gettextln "The following path is ignored by one of your .gitignore files:
-\$sm_path
-Use -f if you really want to add it." >&2
-		exit 1
+	    dryerr=$(git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" 2>&1 >/dev/null)
+	    res=$?
+	    if test $res -ne 0
+	    then
+		 echo >&2 "$dryerr"
+		 exit $res
+	    fi
 	fi
 
 	if test -n "$custom_name"

t/t7400-submodule-basic.sh

@@ -156,9 +156,9 @@ test_expect_success 'submodule add to .gitignored path fails' '
 	(
 		cd addtest-ignore &&
 		cat <<-\EOF >expect &&
-		The following path is ignored by one of your .gitignore files:
+		The following paths are ignored by one of your .gitignore files:
 		submod
-		Use -f if you really want to add it.
+		Use -f if you really want to add them.
 		EOF
 		# Does not use test_commit due to the ignore
 		echo "*" > .gitignore &&
@@ -191,6 +191,17 @@ test_expect_success 'submodule add to reconfigure existing submodule with --forc
 	)
 '
 
+test_expect_success 'submodule add relays add --dry-run stderr' '
+	test_when_finished "rm -rf addtest/.git/index.lock" &&
+	(
+		cd addtest &&
+		: >.git/index.lock &&
+		! git submodule add "$submodurl" sub-while-locked 2>output.err &&
+		test_i18ngrep "^fatal: .*index\.lock" output.err &&
+		test_path_is_missing sub-while-locked
+	)
+'
+
 test_expect_success 'submodule add --branch' '
 	echo "refs/heads/initial" >expect-head &&
 	cat <<-\EOF >expect-heads &&