Merge branch 'da/user-useconfigonly'

The "user.useConfigOnly" configuration variable can be used to
force the user to always set user.email & user.name configuration
variables, serving as a reminder for those who work on multiple
projects and do not want to put these in their $HOME/.gitconfig.

* da/user-useconfigonly:
  ident: add user.useConfigOnly boolean for when ident shouldn't be guessed
  fmt_ident: refactor strictness checks

t/t7517-per-repo-email.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+#
+# Copyright (c) 2016 Dan Aloni
+# Copyright (c) 2016 Jeff King
+#
+
+test_description='per-repo forced setting of email address'
+
+. ./test-lib.sh
+
+test_expect_success 'setup a likely user.useConfigOnly use case' '
+	# we want to make sure a reflog is written, since that needs
+	# a non-strict ident. So be sure we have an actual commit.
+	test_commit foo &&
+
+	sane_unset GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL &&
+	sane_unset GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL &&
+	git config user.name "test" &&
+	git config --global user.useConfigOnly true
+'
+
+test_expect_success 'fails committing if clone email is not set' '
+	test_must_fail git commit --allow-empty -m msg
+'
+
+test_expect_success 'fails committing if clone email is not set, but EMAIL set' '
+	test_must_fail env EMAIL=test@fail.com git commit --allow-empty -m msg
+'
+
+test_expect_success 'succeeds committing if clone email is set' '
+	test_config user.email "test@ok.com" &&
+	git commit --allow-empty -m msg
+'
+
+test_expect_success 'succeeds cloning if global email is not set' '
+	git clone . clone
+'
+
+test_done