As Peff said, responding in a thread started by Linus's suggestion
to raise the default abbreviation to 12 hexdigits:
I actually think "12" might be sane for a long time. That's 48 bits of
sha1, so we'd expect a 50% change of a _single_ collision at 2^24, or 16
million. The biggest repository I know about (in number of objects) is
the one holding all of the objects for all of the forks of
torvalds/linux on GitHub. It's at about 15 million objects.
Which _seems_ close, but remember that's the size where we expect to see
a single collision. They don't become common until much later (I didn't
compute an exact number, but Linus's 16x sounds about right). I know
that the growth of the kernel isn't really linear, but I think the need
to bump to "13" might not just be decades, but possibly a century or
more.
So 12 seems reasonable, and the only downside for it (or for "13", for
that matter) is a few extra bytes. I dunno, maybe people will really
hate that, but I have a feeling these are mostly cut-and-pasted anyway.
And this does exactly that.
Keep the tests working by explicitly asking for the old 7 hexdigits
setting in the fake system-wide configuration file used for tests.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
environment.c | 2 +-
t/gitconfig-for-test | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/environment.c b/environment.c
index ca72464..25daddb 100644
--- a/environment.c
+++ b/environment.c
@@ -16,7 +16,7 @@ int trust_executable_bit = 1;
int trust_ctime = 1;
int check_stat = 1;
int has_symlinks = 1;
-int minimum_abbrev = 4, default_abbrev = 7;
+int minimum_abbrev = 4, default_abbrev = 12;
int ignore_case;
int assume_unchanged;
int prefer_symlink_refs;
diff --git a/t/gitconfig-for-test b/t/gitconfig-for-test
index 4598885..8c28442 100644
--- a/t/gitconfig-for-test
+++ b/t/gitconfig-for-test
@@ -4,3 +4,6 @@
;; [user]
;; name = A U Thor
;; email = author@xxxxxxxxxxx
+
+[core]
+ abbrev = 7
--
2.10.0-584-gc9e068c