setdiscovery: fix hang when #heads>200 (issue2971)
When setting up the next sample, we always add all of the heads, regardless
of the desired max sample size. But if the number of heads exceeds this
size, then we don't add any more nodes from the still undecided set.
(This is debatable per se, and I'll investigate it, but it's how we designed
it at the moment.)
The bug was that we always added the overall heads, not the heads of the
remaining undecided set. Thus, if #heads>200 (desired sample size), we
did not make progress any longer.
Function to test discovery between two repos in both directions, using both the local shortcut
(which is currently not activated by default) and the full remotable protocol:
$ testdesc() { # revs_a, revs_b, dagdesc
> if [ -d foo ]; then rm -rf foo; fi
> hg init foo
> cd foo
> hg debugbuilddag "$3"
> hg clone . a $1 --quiet
> hg clone . b $2 --quiet
> echo
> echo "% -- a -> b tree"
> hg -R a debugdiscovery b --verbose --old
> echo
> echo "% -- a -> b set"
> hg -R a debugdiscovery b --verbose --debug
> echo
> echo "% -- b -> a tree"
> hg -R b debugdiscovery a --verbose --old
> echo
> echo "% -- b -> a set"
> hg -R b debugdiscovery a --verbose --debug
> cd ..
> }
Small superset:
$ testdesc '-ra1 -ra2' '-rb1 -rb2 -rb3' '
> +2:f +1:a1:b1
> <f +4 :a2
> +5 :b2
> <f +3 :b3'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: b5714e113bc0 66f7d451a68b 01241442b3c2
common heads: b5714e113bc0 01241442b3c2
local is subset
% -- a -> b set
comparing with b
query 1; heads
searching for changes
all local heads known remotely
common heads: b5714e113bc0 01241442b3c2
local is subset
% -- b -> a tree
comparing with a
searching for changes
unpruned common: b5714e113bc0 01241442b3c2
common heads: b5714e113bc0 01241442b3c2
remote is subset
% -- b -> a set
comparing with a
query 1; heads
searching for changes
all remote heads known locally
common heads: b5714e113bc0 01241442b3c2
remote is subset
Many new:
$ testdesc '-ra1 -ra2' '-rb' '
> +2:f +3:a1 +3:b
> <f +30 :a2'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: bebd167eb94d
common heads: bebd167eb94d
% -- a -> b set
comparing with b
query 1; heads
searching for changes
taking initial sample
searching: 2 queries
query 2; still undecided: 29, sample size is: 29
2 total queries
common heads: bebd167eb94d
% -- b -> a tree
comparing with a
searching for changes
unpruned common: bebd167eb94d 66f7d451a68b
common heads: bebd167eb94d
% -- b -> a set
comparing with a
query 1; heads
searching for changes
taking initial sample
searching: 2 queries
query 2; still undecided: 2, sample size is: 2
2 total queries
common heads: bebd167eb94d
Both sides many new with stub:
$ testdesc '-ra1 -ra2' '-rb' '
> +2:f +2:a1 +30 :b
> <f +30 :a2'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: 2dc09a01254d
common heads: 2dc09a01254d
% -- a -> b set
comparing with b
query 1; heads
searching for changes
taking initial sample
searching: 2 queries
query 2; still undecided: 29, sample size is: 29
2 total queries
common heads: 2dc09a01254d
% -- b -> a tree
comparing with a
searching for changes
unpruned common: 66f7d451a68b 2dc09a01254d
common heads: 2dc09a01254d
% -- b -> a set
comparing with a
query 1; heads
searching for changes
taking initial sample
searching: 2 queries
query 2; still undecided: 29, sample size is: 29
2 total queries
common heads: 2dc09a01254d
Both many new:
$ testdesc '-ra' '-rb' '
> +2:f +30 :b
> <f +30 :a'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: 66f7d451a68b
common heads: 66f7d451a68b
% -- a -> b set
comparing with b
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 31, sample size is: 31
2 total queries
common heads: 66f7d451a68b
% -- b -> a tree
comparing with a
searching for changes
unpruned common: 66f7d451a68b
common heads: 66f7d451a68b
% -- b -> a set
comparing with a
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 31, sample size is: 31
2 total queries
common heads: 66f7d451a68b
Both many new skewed:
$ testdesc '-ra' '-rb' '
> +2:f +30 :b
> <f +50 :a'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: 66f7d451a68b
common heads: 66f7d451a68b
% -- a -> b set
comparing with b
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 51, sample size is: 51
2 total queries
common heads: 66f7d451a68b
% -- b -> a tree
comparing with a
searching for changes
unpruned common: 66f7d451a68b
common heads: 66f7d451a68b
% -- b -> a set
comparing with a
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 31, sample size is: 31
2 total queries
common heads: 66f7d451a68b
Both many new on top of long history:
$ testdesc '-ra' '-rb' '
> +1000:f +30 :b
> <f +50 :a'
% -- a -> b tree
comparing with b
searching for changes
unpruned common: 7ead0cba2838
common heads: 7ead0cba2838
% -- a -> b set
comparing with b
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 1049, sample size is: 11
sampling from both directions
searching: 3 queries
query 3; still undecided: 31, sample size is: 31
3 total queries
common heads: 7ead0cba2838
% -- b -> a tree
comparing with a
searching for changes
unpruned common: 7ead0cba2838
common heads: 7ead0cba2838
% -- b -> a set
comparing with a
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 1029, sample size is: 11
sampling from both directions
searching: 3 queries
query 3; still undecided: 15, sample size is: 15
3 total queries
common heads: 7ead0cba2838
One with >200 heads, which used to use up all of the sample:
$ hg init manyheads
$ cd manyheads
$ echo "+300:r @a" >dagdesc
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3 *r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3*r+3" >>dagdesc # 20 heads
$ echo "@b *r+3" >>dagdesc # one more head
$ hg debugbuilddag <dagdesc
reading DAG from stdin
$ hg heads -t --template . | wc -c
261
$ hg clone -b a . a
adding changesets
adding manifests
adding file changes
added 1340 changesets with 0 changes to 0 files (+259 heads)
updating to branch a
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone -b b . b
adding changesets
adding manifests
adding file changes
added 304 changesets with 0 changes to 0 files
updating to branch b
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R a debugdiscovery b --debug --verbose
comparing with b
query 1; heads
searching for changes
taking quick initial sample
searching: 2 queries
query 2; still undecided: 1080, sample size is: 260
sampling from both directions
searching: 3 queries
query 3; still undecided: 820, sample size is: 260
sampling from both directions
searching: 4 queries
query 4; still undecided: 560, sample size is: 260
sampling from both directions
searching: 5 queries
query 5; still undecided: 300, sample size is: 200
5 total queries
common heads: 3ee37d65064a