git checkout -b: allow switching out of an unborn branch
Running "git checkout -b another" immediately after "git init" when you do not even have a commit on 'master' fails with: $ git checkout -b another fatal: You are on a branch yet to be born This is unnecessary, if we redefine "git checkout -b $name" that does not take any $start_point (which has to be a commit) as "I want to check out a new branch $name from the state I am in". Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano committed
Jan 30, 2012 at 12:10 UTC
abe199808c6586047fb7255b80e3d17ffc26bf6c
2 files changed
+29
-1
builtin/checkout.c
+19
@@ -916,6 +916,17 @@ static int parse_branchname_arg(int argc, const char **argv,
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return argcount;
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}
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+static int switch_unborn_to_new_branch(struct checkout_opts *opts)
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+{
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+ int status;
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+ struct strbuf branch_ref = STRBUF_INIT;
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+
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+ strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
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+ status = create_symref("HEAD", branch_ref.buf, "checkout -b");
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+ strbuf_release(&branch_ref);
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+ return status;
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+}
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+
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int cmd_checkout(int argc, const char **argv, const char *prefix)
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{
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struct checkout_opts opts;
@@ -1089,5 +1100,13 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
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if (opts.writeout_stage)
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die(_("--ours/--theirs is incompatible with switching branches."));
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+ if (!new.commit) {
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+ unsigned char rev[20];
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+ int flag;
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+
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+ resolve_ref("HEAD", rev, 0, &flag);
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+ if ((flag & REF_ISSYMREF) && is_null_sha1(rev))
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+ return switch_unborn_to_new_branch(&opts);
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+ }
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return switch_branches(&opts, &new);
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}
t/t2015-checkout-unborn.sh
+10
-1
@@ -1,6 +1,6 @@
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#!/bin/sh
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-test_description='checkout from unborn branch protects contents'
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+test_description='checkout from unborn branch'
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. ./test-lib.sh
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test_expect_success 'setup' '
@@ -37,4 +37,13 @@ test_expect_success 'checkout from unborn merges identical index contents' '
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git checkout -b new origin
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'
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+test_expect_success 'checking out another branch from unborn state' '
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+ git checkout --orphan newroot &&
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+ git checkout -b anothername &&
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+ test_must_fail git show-ref --verify refs/heads/newroot &&
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+ git symbolic-ref HEAD >actual &&
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+ echo refs/heads/anothername >expect &&
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+ test_cmp expect actual
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+'
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+
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test_done