In certain cases +find-merge-points was very slow. Specifically, the
`done` set was meant to avoid checking the same commit repeatedly, but
it didn't catch the case where a commit was added to the worklist that
was already in that worklist.
Secondly, the worklist was stored as a list but used as a queue, which
resulted in a lot of unnecessary welding. We change it to a qeu.
Fixes#3735
If both sides changed a file in the same way, %mate used the version in
the mergebase, which is incorrect. This changes it to use the version
in the destination desk.
An example of this issue:
> +cat %/test/hoon
/~zod/home/~2020.9.3..21.41.24..61ed/test/hoon
first
> |merge %scratch our %home
>=
merged with strategy %fine
+ /~zod/scratch/2/test/hoon
> +cat /=scratch=/test
/~zod/scratch/~2020.9.3..21.41.32..408c/test/hoon
first
> *%/test/hoon 'second'
: /~zod/home/3/test/hoon
> *%%%/scratch=/test/hoon 'second'
: /~zod/scratch/3/test/hoon
> |merge %scratch our %home
>=
%fine merge failed, trying %meet
%meet merge failed, trying %mate
merged with strategy %mate
: /~zod/scratch/4/test/hoon
> +cat /=scratch=/test
/~zod/scratch/~2020.9.3..21.42.25..9e8b/test/hoon
first
The main thing here is that we aggressively check whether we're in
ancestry of another mergebase candidate. This means we don't have to do
a 2nd pass to eliminate redundant candidates.
Change the definition of base-hash to be the mergebase of %home with the
OTA source. This means it's the most recent successfully-applied
update, which is usually the most important information.
Add sour-hash, which is the hash of the most recently *downloaded*
update, regardless of whether it applied successfuly (ie the old
base-hash).
Add a summary of the various hashes at the top of gen/trouble.
Only no-op if the incoming commit's parent is the old head of the desk.
Also move the printing near the end so we can know exactly if anything
changed.
When merging, +reachable-takos is called roughly once per merge commit
in the ancestry of the new commit. +reachable-takos was exponential in
the number of merge commits in the ancestry of the commit it's looking
at, due to mishandling of the accumulator. This makes it linear.
Of course, linear x linear is still quadratic, which is not great. I
doubt +reachable-takos can be made asymptotically better, but
+reduce-merge-points/+find-merge-points probably can. 50 merge commits
already gives about 14.000 iterations through the loop in
+reachable-takos. Another option is to try to memoize this somehow, but
a simple ~+ is insufficient since `s` is usually different.
In local tests on macOS with a -L copy of ~wicdev-wisryt, this speeds up
OTAs significantly. The majority of time was spent on this.
We build a reef for each desk but use the compiler from our kernel. At
some point we should use the compiler from the desk, but then we need to
validate any results we get from it.
We need to get updates directly into %home in case the marks depend on
changes to hoon.hoon. %base has no reason to exist.
Our ota strategy is now to merge from parent/kids to home, then
parent/kids to kids.
