Christian Couder
4360734e90
If a repository R is configured to lazy fetch from a promisor remote P
which is also configured to in turn lazy fetch from R, there is an
infinite recursion: R asks P for a missing object, P asks R for it,
and so on. The simplest case of this is a repository configured as its
own promisor remote.
This is not reachable when serving a repository by default, as
`upload-pack` sets `GIT_NO_LAZY_FETCH` to 1, which makes the nested
`upload-pack` refuse to lazily fetch. A following commit will let
server operators allow lazy fetching for repositories they trust
though, and as `GIT_NO_LAZY_FETCH` is then set to 0 and passed down to
child processes, nothing stops the recursion anymore.
It does not recurse forever in practice, but only because each level
adds one more variable to the environment of the child process, so
after a while `exec()` fails with:
fatal: cannot exec 'git-upload-pack ...': Argument list too long
fatal: unable to fork
To avoid this pathological case altogether, let's use a new
`GIT_INTERNAL_LAZY_FETCH_DEPTH` to count the recursion depth, and let's
check that it doesn't exceed a MAX_LAZY_FETCH_DEPTH limit (set to 5 for
now).
Note that some nesting is legitimate: when `git fetch` runs
`index-pack`, it can lazily fetch REF_DELTA bases that are missing
locally, so the limit should not be 1.
Signed-off-by: Christian Couder <christian.couder@gmail.com>
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.
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Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.adoc to get started, then see
Documentation/giteveryday.adoc for a useful minimum set of commands, and
Documentation/git-<commandname>.adoc 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.adoc
(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