Merge branch 'jk/maint-1.6.3-checkout-unborn' into maint

* jk/maint-1.6.3-checkout-unborn:
  checkout: do not imply "-f" on unborn branches

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 8a9a474218c128b7878647045ba471df9902636a..c6d6ac99f63459094d3e1a110fed228a74f7927b 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -402,7 +402,9 @@ static int merge_working_tree(struct checkout_opts *opts,
                topts.dir = xcalloc(1, sizeof(*topts.dir));
                topts.dir->flags |= DIR_SHOW_IGNORED;
                topts.dir->exclude_per_dir = ".gitignore";
-               tree = parse_tree_indirect(old->commit->object.sha1);
+               tree = parse_tree_indirect(old->commit ?
+                                          old->commit->object.sha1 :
+                                          (unsigned char *)EMPTY_TREE_SHA1_BIN);
                init_tree_desc(&trees[0], tree->buffer, tree->size);
                tree = parse_tree_indirect(new->commit->object.sha1);
                init_tree_desc(&trees[1], tree->buffer, tree->size);
@@ -541,14 +543,6 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
                parse_commit(new->commit);
        }
 
-       if (!old.commit && !opts->force) {
-               if (!opts->quiet) {
-                       warning("You appear to be on a branch yet to be born.");
-                       warning("Forcing checkout of %s.", new->name);
-               }
-               opts->force = 1;
-       }
-
        ret = merge_working_tree(opts, &old, new);
        if (ret)
                return ret;

diff --git a/t/t2015-checkout-unborn.sh b/t/t2015-checkout-unborn.sh
new file mode 100755 (executable)
index 0000000..c551d39
--- /dev/null
+++ b/t/t2015-checkout-unborn.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+
+test_description='checkout from unborn branch protects contents'
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+       mkdir parent &&
+       (cd parent &&
+        git init &&
+        echo content >file &&
+        git add file &&
+        git commit -m base
+       ) &&
+       git fetch parent master:origin
+'
+
+test_expect_success 'checkout from unborn preserves untracked files' '
+       echo precious >expect &&
+       echo precious >file &&
+       test_must_fail git checkout -b new origin &&
+       test_cmp expect file
+'
+
+test_expect_success 'checkout from unborn preserves index contents' '
+       echo precious >expect &&
+       echo precious >file &&
+       git add file &&
+       test_must_fail git checkout -b new origin &&
+       test_cmp expect file &&
+       git show :file >file &&
+       test_cmp expect file
+'
+
+test_expect_success 'checkout from unborn merges identical index contents' '
+       echo content >file &&
+       git add file &&
+       git checkout -b new origin
+'
+
+test_done