I was recently pointed to a repository where:
git log --format="%H %P" old..new
was abysmally slow, even though old..new only had a few commits, because
load_ref_decorations() takes a long time (and kicks in due to the
auto-decorate behavior). Leaving aside that "rev-list" would probably be
a better tool here, it seems there's some low-hanging fruit:
- a user-format that doesn't show decorations doesn't need to load
them (fixed in patch 2 below)
- we're pretty eager to parse the objects at the tip of each ref
(fixed in patch 5 below)
The other commits are just cleanups and preparatory refactors.
[1/5]: pretty.h: update and expand docstring for userformat_find_requirements()
[2/5]: log: avoid loading decorations for userformats that don't need it
[3/5]: object.h: expand docstring for lookup_unknown_object()
[4/5]: object.h: add lookup_object_by_type() function
[5/5]: load_ref_decorations(): avoid parsing non-tag objects
builtin/log.c | 3 +++
log-tree.c | 6 ++++--
object.c | 18 ++++++++++++++++++
object.h | 20 +++++++++++++++++++-
pretty.c | 4 ++++
pretty.h | 8 ++++++--
reachable.c | 18 ------------------
7 files changed, 54 insertions(+), 23 deletions(-)
-Peff
