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view tests/test-convert-cvs-detectmerge.t @ 32697:19b9fc40cc51
revlog: skeleton support for version 2 revlogs
There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.
It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.
This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.
An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.
To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.
Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.
There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 19 May 2017 20:29:11 -0700 |
parents | 96529f81e2e9 |
children | e5e5ee2b60e4 |
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#require cvs Test config convert.cvsps.mergefrom config setting. (Should test similar mergeto feature, but I don't understand it yet.) Requires builtin cvsps. $ CVSROOT=`pwd`/cvsrepo $ export CVSROOT $ cvscall() > { > cvs -f "$@" > } output of 'cvs ci' varies unpredictably, so just discard it XXX copied from test-convert-cvs-synthetic $ cvsci() > { > sleep 1 > cvs -f ci "$@" > /dev/null > } XXX copied from test-convert-cvs-synthetic $ cat <<EOF >> $HGRCPATH > [extensions] > convert = > [convert] > cvsps.cache = 0 > cvsps.mergefrom = \[MERGE from (\S+)\] > EOF create cvs repository with one project $ cvscall -q -d "$CVSROOT" init $ mkdir cvsrepo/proj populate cvs repository $ cvscall -Q co proj $ cd proj $ touch file1 $ cvscall -Q add file1 $ cvsci -m"add file1 on trunk" cvs commit: Examining . create two release branches $ cvscall -q tag -b v1_0 T file1 $ cvscall -q tag -b v1_1 T file1 modify file1 on branch v1_0 $ cvscall -Q update -rv1_0 $ sleep 1 $ echo "change" >> file1 $ cvsci -m"add text" cvs commit: Examining . make unrelated change on v1_1 $ cvscall -Q update -rv1_1 $ touch unrelated $ cvscall -Q add unrelated $ cvsci -m"unrelated change" cvs commit: Examining . merge file1 to v1_1 $ cvscall -Q update -jv1_0 RCS file: $TESTTMP/cvsrepo/proj/file1,v retrieving revision 1.1 retrieving revision 1.1.2.1 Merging differences between 1.1 and 1.1.2.1 into file1 $ cvsci -m"add text [MERGE from v1_0]" cvs commit: Examining . merge change to trunk $ cvscall -Q update -A $ cvscall -Q update -jv1_1 RCS file: $TESTTMP/cvsrepo/proj/file1,v retrieving revision 1.1 retrieving revision 1.1.4.1 Merging differences between 1.1 and 1.1.4.1 into file1 $ cvsci -m"add text [MERGE from v1_1]" cvs commit: Examining . non-merged change on trunk $ echo "foo" > file2 $ cvscall -Q add file2 $ cvsci -m"add file2 on trunk" file2 this will create rev 1.3 change on trunk to backport $ echo "backport me" >> file1 $ cvsci -m"add other text" file1 $ cvscall log file1 RCS file: $TESTTMP/cvsrepo/proj/file1,v Working file: file1 head: 1.3 branch: locks: strict access list: symbolic names: v1_1: 1.1.0.4 v1_0: 1.1.0.2 keyword substitution: kv total revisions: 5; selected revisions: 5 description: ---------------------------- revision 1.3 date: * (glob) add other text ---------------------------- revision 1.2 date: * (glob) add text [MERGE from v1_1] ---------------------------- revision 1.1 date: * (glob) branches: 1.1.2; 1.1.4; add file1 on trunk ---------------------------- revision 1.1.4.1 date: * (glob) add text [MERGE from v1_0] ---------------------------- revision 1.1.2.1 date: * (glob) add text ============================================================================= XXX how many ways are there to spell "trunk" with CVS? backport trunk change to v1_1 $ cvscall -Q update -rv1_1 $ cvscall -Q update -j1.2 -j1.3 file1 RCS file: $TESTTMP/cvsrepo/proj/file1,v retrieving revision 1.2 retrieving revision 1.3 Merging differences between 1.2 and 1.3 into file1 $ cvsci -m"add other text [MERGE from HEAD]" file1 fix bug on v1_1, merge to trunk with error $ cvscall -Q update -rv1_1 $ echo "merge forward" >> file1 $ cvscall -Q tag unmerged $ cvsci -m"fix file1" cvs commit: Examining . $ cvscall -Q update -A $ cvscall -Q update -junmerged -jv1_1 RCS file: $TESTTMP/cvsrepo/proj/file1,v retrieving revision 1.1.4.2 retrieving revision 1.1.4.3 Merging differences between 1.1.4.2 and 1.1.4.3 into file1 note the typo in the commit log message $ cvsci -m"fix file1 [MERGE from v1-1]" cvs commit: Examining . $ cvs -Q tag -d unmerged convert to hg $ cd .. $ hg convert proj proj.hg initializing destination proj.hg repository connecting to $TESTTMP/cvsrepo scanning source... collecting CVS rlog 12 log entries creating changesets warning: CVS commit message references non-existent branch 'v1-1': fix file1 [MERGE from v1-1] 10 changeset entries sorting... converting... 9 add file1 on trunk 8 unrelated change 7 add text 6 add text [MERGE from v1_0] 5 add text [MERGE from v1_1] 4 add file2 on trunk 3 add other text 2 add other text [MERGE from HEAD] 1 fix file1 0 fix file1 [MERGE from v1-1] complete log $ template="{rev}: '{branches}' {desc}\n" $ hg -R proj.hg log --template="$template" 9: '' fix file1 [MERGE from v1-1] 8: 'v1_1' fix file1 7: 'v1_1' add other text [MERGE from HEAD] 6: '' add other text 5: '' add file2 on trunk 4: '' add text [MERGE from v1_1] 3: 'v1_1' add text [MERGE from v1_0] 2: 'v1_0' add text 1: 'v1_1' unrelated change 0: '' add file1 on trunk graphical log $ hg -R proj.hg log -G --template="$template" o 9: '' fix file1 [MERGE from v1-1] | | o 8: 'v1_1' fix file1 | | | o 7: 'v1_1' add other text [MERGE from HEAD] |/| o | 6: '' add other text | | o | 5: '' add file2 on trunk | | o | 4: '' add text [MERGE from v1_1] |\| | o 3: 'v1_1' add text [MERGE from v1_0] | |\ +---o 2: 'v1_0' add text | | | o 1: 'v1_1' unrelated change |/ o 0: '' add file1 on trunk