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% chance 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 ca72464a9850..25daddbc13d6 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 4598885ed5c3..8c284425d725 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
--
2.10.0-589-g5adf4e1