Mercurial > hg-stable
view tests/test-rebase-cache.t @ 26457:7e81305092a0
demandimport: replace more references to _demandmod instances
_demandmod instances may be referenced by multiple importing modules.
Before this patch, the _demandmod instance only maintained a reference
to its first consumer when using the "from X import Y" syntax. This is
because we only created a single _demandmod instance (attached to the
parent X module). If multiple modules A and B performed
"from X import Y", we'd produce a single _demandmod instance
"demandmod" with the following references:
X.Y = <demandmod>
A.Y = <demandmod>
B.Y = <demandmod>
The locals from the first consumer (A) would be stored in <demandmod1>.
When <demandmod1> was loaded, we'd look at the locals for the first
consumer and replace the symbol, if necessary. This resulted in state:
X.Y = <module>
A.Y = <module>
B.Y = <demandmod>
B's reference to Y wasn't updated and was still using the proxy object
because we just didn't record that B had a reference to <demandmod> that
needed updating!
With this patch, we add support for tracking which modules in addition
to the initial importer have a reference to the _demandmod instance and
we replace those references at module load time.
In the case of posix.py, this fixes an issue where the "encoding" module
was being proxied, resulting in hundreds of thousands of
__getattribute__ lookups on the _demandmod instance during dirstate
operations on mozilla-central, speeding up execution by many
milliseconds. There are likely several other operation that benefit from
this change as well.
The new mechanism isn't perfect: references in locals (not globals) may
likely linger. So, if there is an import inside a function and a symbol
from that module is used in a hot loop, we could have unwanted overhead
from proxying through _demandmod. Non-global imports are discouraged
anyway. So hopefully this isn't a big deal in practice. We could
potentially deploy a code checker that bans use of attribute lookups of
function-level-imported modules inside loops.
This deficiency in theory could be avoided by storing the set of globals
and locals dicts to update in the _demandmod instance. However, I tried
this and it didn't work. One reason is that some globals are _demandmod
instances. We could work around this, but it's a bit more work. There
also might be other module import foo at play. The solution as
implemented is better than what we had and IMO is good enough for the
time being.
It's worth noting that this sub-optimal behavior was made worse by the
introduction of absolute_import and its recommended "from . import X"
syntax for importing modules from the "mercurial" package. If we ever
wrote performance tests, measuring the amount of module imports and
__getattribute__ proxy calls through _demandmod instances would be
something I'd have it check.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 04 Oct 2015 11:17:43 -0700 |
parents | 701df761aa94 |
children | 3b7cb3d17137 |
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$ cat >> $HGRCPATH <<EOF > [extensions] > rebase= > mq= > > [phases] > publish=False > > [alias] > tglog = log -G --template "{rev}: '{desc}' {branches}\n" > theads = heads --template "{rev}: '{desc}' {branches}\n" > EOF $ hg init a $ cd a $ echo a > a $ hg ci -Am A adding a $ hg branch branch1 marked working directory as branch branch1 (branches are permanent and global, did you want a bookmark?) $ hg ci -m 'branch1' $ echo b > b $ hg ci -Am B adding b $ hg up -q 0 $ hg branch branch2 marked working directory as branch branch2 $ hg ci -m 'branch2' $ echo c > C $ hg ci -Am C adding C $ hg up -q 2 $ hg branch -f branch2 marked working directory as branch branch2 $ echo d > d $ hg ci -Am D adding d created new head $ echo e > e $ hg ci -Am E adding e $ hg update default 0 files updated, 0 files merged, 3 files removed, 0 files unresolved $ hg branch branch3 marked working directory as branch branch3 $ hg ci -m 'branch3' $ echo f > f $ hg ci -Am F adding f $ cd .. Rebase part of branch2 (5-6) onto branch3 (8): $ hg clone -q -u . a a1 $ cd a1 $ hg tglog @ 8: 'F' branch3 | o 7: 'branch3' branch3 | | o 6: 'E' branch2 | | | o 5: 'D' branch2 | | | | o 4: 'C' branch2 | | | +---o 3: 'branch2' branch2 | | | o 2: 'B' branch1 | | | o 1: 'branch1' branch1 |/ o 0: 'A' $ hg branches branch3 8:4666b71e8e32 branch2 6:5097051d331d branch1 2:0a03079c47fd (inactive) default 0:1994f17a630e (inactive) $ hg theads 8: 'F' branch3 6: 'E' branch2 4: 'C' branch2 2: 'B' branch1 0: 'A' $ hg rebase -s 5 -d 8 rebasing 5:635859577d0b "D" rebasing 6:5097051d331d "E" saved backup bundle to $TESTTMP/a1/.hg/strip-backup/635859577d0b-89160bff-backup.hg (glob) $ hg branches branch3 8:466cdfb14b62 branch2 4:e4fdb121d036 branch1 2:0a03079c47fd default 0:1994f17a630e (inactive) $ hg theads 8: 'E' branch3 4: 'C' branch2 2: 'B' branch1 0: 'A' $ hg tglog o 8: 'E' branch3 | o 7: 'D' branch3 | @ 6: 'F' branch3 | o 5: 'branch3' branch3 | | o 4: 'C' branch2 | | | o 3: 'branch2' branch2 |/ | o 2: 'B' branch1 | | | o 1: 'branch1' branch1 |/ o 0: 'A' $ cd .. Rebase head of branch3 (8) onto branch2 (6): $ hg clone -q -u . a a2 $ cd a2 $ hg tglog @ 8: 'F' branch3 | o 7: 'branch3' branch3 | | o 6: 'E' branch2 | | | o 5: 'D' branch2 | | | | o 4: 'C' branch2 | | | +---o 3: 'branch2' branch2 | | | o 2: 'B' branch1 | | | o 1: 'branch1' branch1 |/ o 0: 'A' $ hg rebase -s 8 -d 6 rebasing 8:4666b71e8e32 "F" (tip) saved backup bundle to $TESTTMP/a2/.hg/strip-backup/4666b71e8e32-fc1c4e96-backup.hg (glob) $ hg branches branch2 8:6b4bdc1b5ac0 branch3 7:653b9feb4616 branch1 2:0a03079c47fd (inactive) default 0:1994f17a630e (inactive) $ hg theads 8: 'F' branch2 7: 'branch3' branch3 4: 'C' branch2 2: 'B' branch1 0: 'A' $ hg tglog @ 8: 'F' branch2 | | o 7: 'branch3' branch3 | | o | 6: 'E' branch2 | | o | 5: 'D' branch2 | | | | o 4: 'C' branch2 | | | | | o 3: 'branch2' branch2 | |/ o | 2: 'B' branch1 | | o | 1: 'branch1' branch1 |/ o 0: 'A' $ hg verify -q $ cd .. Rebase entire branch3 (7-8) onto branch2 (6): $ hg clone -q -u . a a3 $ cd a3 $ hg tglog @ 8: 'F' branch3 | o 7: 'branch3' branch3 | | o 6: 'E' branch2 | | | o 5: 'D' branch2 | | | | o 4: 'C' branch2 | | | +---o 3: 'branch2' branch2 | | | o 2: 'B' branch1 | | | o 1: 'branch1' branch1 |/ o 0: 'A' $ hg rebase -s 7 -d 6 rebasing 7:653b9feb4616 "branch3" note: rebase of 7:653b9feb4616 created no changes to commit rebasing 8:4666b71e8e32 "F" (tip) saved backup bundle to $TESTTMP/a3/.hg/strip-backup/653b9feb4616-3c88de16-backup.hg (glob) $ hg branches branch2 7:6b4bdc1b5ac0 branch1 2:0a03079c47fd (inactive) default 0:1994f17a630e (inactive) $ hg theads 7: 'F' branch2 4: 'C' branch2 2: 'B' branch1 0: 'A' $ hg tglog @ 7: 'F' branch2 | o 6: 'E' branch2 | o 5: 'D' branch2 | | o 4: 'C' branch2 | | | o 3: 'branch2' branch2 | | o | 2: 'B' branch1 | | o | 1: 'branch1' branch1 |/ o 0: 'A' $ hg verify -q Stripping multiple branches in one go bypasses the fast-case code to update the branch cache. $ hg strip 2 0 files updated, 0 files merged, 4 files removed, 0 files unresolved saved backup bundle to $TESTTMP/a3/.hg/strip-backup/0a03079c47fd-11b7c407-backup.hg (glob) $ hg tglog o 3: 'C' branch2 | o 2: 'branch2' branch2 | | @ 1: 'branch1' branch1 |/ o 0: 'A' $ hg branches branch2 3:e4fdb121d036 branch1 1:63379ac49655 default 0:1994f17a630e (inactive) $ hg theads 3: 'C' branch2 1: 'branch1' branch1 0: 'A' Fast path branchcache code should not be invoked if branches stripped is not the same as branches remaining. $ hg init b $ cd b $ hg branch branch1 marked working directory as branch branch1 (branches are permanent and global, did you want a bookmark?) $ hg ci -m 'branch1' $ hg branch branch2 marked working directory as branch branch2 $ hg ci -m 'branch2' $ hg branch -f branch1 marked working directory as branch branch1 $ echo a > A $ hg ci -Am A adding A created new head $ hg tglog @ 2: 'A' branch1 | o 1: 'branch2' branch2 | o 0: 'branch1' branch1 $ hg theads 2: 'A' branch1 1: 'branch2' branch2 $ hg strip 2 0 files updated, 0 files merged, 1 files removed, 0 files unresolved saved backup bundle to $TESTTMP/a3/b/.hg/strip-backup/a5b4b27ed7b4-a3b6984e-backup.hg (glob) $ hg theads 1: 'branch2' branch2 0: 'branch1' branch1 Make sure requesting to strip a revision already stripped does not confuse things. Try both orders. $ cd .. $ hg init c $ cd c $ echo a > a $ hg ci -Am A adding a $ echo b > b $ hg ci -Am B adding b $ echo c > c $ hg ci -Am C adding c $ echo d > d $ hg ci -Am D adding d $ echo e > e $ hg ci -Am E adding e $ hg tglog @ 4: 'E' | o 3: 'D' | o 2: 'C' | o 1: 'B' | o 0: 'A' $ hg strip 3 4 0 files updated, 0 files merged, 2 files removed, 0 files unresolved saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/67a385d4e6f2-b9243789-backup.hg (glob) $ hg theads 2: 'C' $ hg strip 2 1 0 files updated, 0 files merged, 2 files removed, 0 files unresolved saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/6c81ed0049f8-a687065f-backup.hg (glob) $ hg theads 0: 'A' Make sure rebase does not break for phase/filter related reason ---------------------------------------------------------------- (issue3858) $ cd .. $ cat >> $HGRCPATH << EOF > [ui] > logtemplate={rev} {desc} {phase}\n > EOF $ hg init c4 $ cd c4 $ echo a > a $ hg ci -Am A adding a $ echo b > b $ hg ci -Am B adding b $ hg up 0 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo c > c $ hg ci -Am C adding c created new head $ hg up 1 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg merge 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg ci -m d $ hg up 2 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo e > e $ hg ci -Am E adding e created new head $ hg merge 3 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg ci -m F $ hg up 3 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo g > g $ hg ci -Am G adding g created new head $ echo h > h $ hg ci -Am H adding h $ hg up 5 1 files updated, 0 files merged, 2 files removed, 0 files unresolved $ echo i > i $ hg ci -Am I adding i Turn most changeset public $ hg ph -p 7 $ hg heads 8 I draft 7 H public $ hg log -G @ 8 I draft | | o 7 H public | | | o 6 G public | | o | 5 F draft |\| o | 4 E draft | | | o 3 d public |/| o | 2 C public | | | o 1 B public |/ o 0 A public $ cat > $TESTTMP/checkeditform.sh <<EOF > env | grep HGEDITFORM > true > EOF $ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg rebase --dest 7 --source 5 -e rebasing 5:361a99976cc9 "F" HGEDITFORM=rebase.merge rebasing 8:326cfedc031c "I" (tip) HGEDITFORM=rebase.normal saved backup bundle to $TESTTMP/a3/c4/.hg/strip-backup/361a99976cc9-35e980d0-backup.hg (glob)