If NO_OPENSSL is defined, then imap-send.c defines a fallback "SSL"
type, which is just a void pointer that remains NULL. This works, but it
has one problem: it is using the type name "SSL", which conflicts with
the upstream name, if some other part of the system happens to include
openssl. For example:
$ make NO_OPENSSL=Nope OPENSSL_SHA1=Yes imap-send.o
CC imap-send.o
imap-send.c:35:15: error: conflicting types for ‘SSL’; have ‘void *’
35 | typedef void *SSL;
| ^~~
In file included from /usr/include/openssl/evp.h:26,
from sha1/openssl.h:4,
from hash.h:10,
from object.h:4,
from commit.h:4,
from refs.h:4,
from setup.h:4,
from imap-send.c:32:
/usr/include/openssl/types.h:187:23: note: previous declaration of ‘SSL’ with type ‘SSL’ {aka ‘struct ssl_st’}
187 | typedef struct ssl_st SSL;
| ^~~
make: *** [Makefile:2761: imap-send.o] Error 1
This is not a terribly common combination in practice:
1. Why are we disabling openssl support but still using its sha1? The
answer is that you may use the same build options across many
versions, and some older versions of Git no longer build with
modern versions of openssl.
2. Why are we using a totally unsafe sha1 that does not detect
collisions? You're right, we shouldn't. But in preparation for
using unsafe sha1 for non-cryptographic checksums, it would be nice
to be able to turn it on without hassle.
We can make this work by adjusting the way imap-send handles its
fallback. One solution is something like this:
#ifdef NO_OPENSSL
#define git_SSL void *
#else
#define git_SSL SSL
#endif
But we can observe that we only need this definition in one spot: the
struct which holds the variable. So rather than play around with macros
that may cause unexpected effects, we can just directly use the correct
type in that struct.
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.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
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
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
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