checkout: implement "-" abbreviation, add docs and tests

Have '-' mean the same as '@{-1}', i.e., the last branch we were on.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 9cd51514dbfd987db4423e254e8bab7284352525..3bccffae628e065a6cd92155a9283d5710991fd7 100644 (file)
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -133,6 +133,10 @@ the conflicted merge in the specified paths.
 +
 When this parameter names a non-branch (but still a valid commit object),
 your HEAD becomes 'detached'.
++
+As a special case, the "`@\{-N\}`" syntax for the N-th last branch
+checks out the branch (instead of detaching).  You may also specify
+"`-`" which is synonymous with "`@\{-1\}`".
 
 
 Detached HEAD

diff --git a/builtin-checkout.c b/builtin-checkout.c
index dc1de06279e2fcdb945e3ec5bdcd0a6f7d06e51b..b0a101bac7432719d62c013d98bb0e6171e45406 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -679,6 +679,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                arg = argv[0];
                has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
 
+               if (!strcmp(arg, "-"))
+                       arg = "@{-1}";
+
                if (get_sha1(arg, rev)) {
                        if (has_dash_dash)          /* case (1) */
                                die("invalid reference: %s", arg);

diff --git a/t/t2012-checkout-last.sh b/t/t2012-checkout-last.sh
new file mode 100755 (executable)
index 0000000..320f6eb
--- /dev/null
+++ b/t/t2012-checkout-last.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+test_description='checkout can switch to last branch'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+       echo hello >world &&
+       git add world &&
+       git commit -m initial &&
+       git branch other &&
+       echo "hello again" >>world &&
+       git add world &&
+       git commit -m second
+'
+
+test_expect_success '"checkout -" does not work initially' '
+       test_must_fail git checkout -
+'
+
+test_expect_success 'first branch switch' '
+       git checkout other
+'
+
+test_expect_success '"checkout -" switches back' '
+       git checkout - &&
+       test "z$(git symbolic-ref HEAD)" = "zrefs/heads/master"
+'
+
+test_expect_success '"checkout -" switches forth' '
+       git checkout - &&
+       test "z$(git symbolic-ref HEAD)" = "zrefs/heads/other"
+'
+
+test_expect_success 'detach HEAD' '
+       git checkout $(git rev-parse HEAD)
+'
+
+test_expect_success '"checkout -" attaches again' '
+       git checkout - &&
+       test "z$(git symbolic-ref HEAD)" = "zrefs/heads/other"
+'
+
+test_expect_success '"checkout -" detaches again' '
+       git checkout - &&
+       test "z$(git rev-parse HEAD)" = "z$(git rev-parse other)" &&
+       test_must_fail git symbolic-ref HEAD
+'
+
+test_done