ee798742bd
The merge-recursive code uses stage number constants like this:
add = &ci->ren1->dst_entry->stages[2 ^ 1];
...
add = &ci->ren2->dst_entry->stages[3 ^ 1];
The xor has the effect of flipping the "1" bit, so that "2 ^ 1" becomes
"3" and "3 ^ 1" becomes "2", which correspond to the "ours" and "theirs"
stages respectively.
Unfortunately, clang-10 and up issue a warning for this code:
merge-recursive.c:1759:40: error: result of '2 ^ 1' is 3; did you mean '1 << 1' (2)? [-Werror,-Wxor-used-as-pow]
add = &ci->ren1->dst_entry->stages[2 ^ 1];
~~^~~
1 << 1
merge-recursive.c:1759:40: note: replace expression with '0x2 ^ 1' to silence this warning
We could silence it by using 0x2, as the compiler mentions. Or by just
using the constants "2" and "3" directly. But after digging into it, I
do think this bit-flip is telling us something. If we just wrote:
add = &ci->ren2->dst_entry->stages[2];
for the second one, you might think that "ren2" and "2" correspond. But
they don't. The logic is: ren2 is theirs, which is stage 3, but we
are interested in the opposite side's stage, so flip it to 2.
So let's keep the bit-flipping, but let's also put it behind a named
function, which will make its purpose a bit clearer. This also has the
side effect of suppressing the warning (and an optimizing compiler
should be able to easily turn it into a constant as before).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
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See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
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The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks