diff.c: emit_diff_symbol learns DIFF_SYMBOL_HEADER

diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index 5d68729d7a65abde09d1293e8569b730d2ba9a40..fbb4ee9bb42dbcfdfcdb79511523a8fa2ac8b5d9 100755 (executable)
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -163,4 +163,27 @@ test_expect_success 'tracking count is accurate after orphan check' '
        test_i18ncmp expect stdout
 '
 
+test_expect_success 'no advice given for explicit detached head state' '
+       # baseline
+       test_config advice.detachedHead true &&
+       git checkout child && git checkout HEAD^0 >expect.advice 2>&1 &&
+       test_config advice.detachedHead false &&
+       git checkout child && git checkout HEAD^0 >expect.no-advice 2>&1 &&
+       test_unconfig advice.detachedHead &&
+       # without configuration, the advice.* variables default to true
+       git checkout child && git checkout HEAD^0 >actual 2>&1 &&
+       test_cmp expect.advice actual &&
+
+       # with explicit --detach
+       # no configuration
+       test_unconfig advice.detachedHead &&
+       git checkout child && git checkout --detach HEAD^0 >actual 2>&1 &&
+       test_cmp expect.no-advice actual &&
+
+       # explicitly decline advice
+       test_config advice.detachedHead false &&
+       git checkout child && git checkout --detach HEAD^0 >actual 2>&1 &&
+       test_cmp expect.no-advice actual
+'
+
 test_done