Mercurial > hg
view tests/test-diff-upgrade.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outdated and unsupported repo format.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 | e955549cd045 |
children | 15ddf83fbf84 |
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#require execbit $ cat <<EOF >> $HGRCPATH > [extensions] > autodiff = $TESTDIR/autodiff.py > [diff] > nodates = 1 > EOF $ hg init repo $ cd repo make a combination of new, changed and deleted file $ echo regular > regular $ echo rmregular > rmregular $ $PYTHON -c "file('bintoregular', 'wb').write('\0')" $ touch rmempty $ echo exec > exec $ chmod +x exec $ echo rmexec > rmexec $ chmod +x rmexec $ echo setexec > setexec $ echo unsetexec > unsetexec $ chmod +x unsetexec $ echo binary > binary $ $PYTHON -c "file('rmbinary', 'wb').write('\0')" $ hg ci -Am addfiles adding binary adding bintoregular adding exec adding regular adding rmbinary adding rmempty adding rmexec adding rmregular adding setexec adding unsetexec $ echo regular >> regular $ echo newregular >> newregular $ rm rmempty $ touch newempty $ rm rmregular $ echo exec >> exec $ echo newexec > newexec $ echo bintoregular > bintoregular $ chmod +x newexec $ rm rmexec $ chmod +x setexec $ chmod -x unsetexec $ $PYTHON -c "file('binary', 'wb').write('\0\0')" $ $PYTHON -c "file('newbinary', 'wb').write('\0')" $ rm rmbinary $ hg addremove -s 0 adding newbinary adding newempty adding newexec adding newregular removing rmbinary removing rmempty removing rmexec removing rmregular git=no: regular diff for all files $ hg autodiff --git=no diff -r a66d19b9302d binary Binary file binary has changed diff -r a66d19b9302d bintoregular Binary file bintoregular has changed diff -r a66d19b9302d exec --- a/exec +++ b/exec @@ -1,1 +1,2 @@ exec +exec diff -r a66d19b9302d newbinary Binary file newbinary has changed diff -r a66d19b9302d newexec --- /dev/null +++ b/newexec @@ -0,0 +1,1 @@ +newexec diff -r a66d19b9302d newregular --- /dev/null +++ b/newregular @@ -0,0 +1,1 @@ +newregular diff -r a66d19b9302d regular --- a/regular +++ b/regular @@ -1,1 +1,2 @@ regular +regular diff -r a66d19b9302d rmbinary Binary file rmbinary has changed diff -r a66d19b9302d rmexec --- a/rmexec +++ /dev/null @@ -1,1 +0,0 @@ -rmexec diff -r a66d19b9302d rmregular --- a/rmregular +++ /dev/null @@ -1,1 +0,0 @@ -rmregular git=yes: git diff for single regular file $ hg autodiff --git=yes regular diff --git a/regular b/regular --- a/regular +++ b/regular @@ -1,1 +1,2 @@ regular +regular git=auto: regular diff for regular files and non-binary removals $ hg autodiff --git=auto regular newregular rmregular rmexec diff -r a66d19b9302d newregular --- /dev/null +++ b/newregular @@ -0,0 +1,1 @@ +newregular diff -r a66d19b9302d regular --- a/regular +++ b/regular @@ -1,1 +1,2 @@ regular +regular diff -r a66d19b9302d rmexec --- a/rmexec +++ /dev/null @@ -1,1 +0,0 @@ -rmexec diff -r a66d19b9302d rmregular --- a/rmregular +++ /dev/null @@ -1,1 +0,0 @@ -rmregular $ for f in exec newexec setexec unsetexec binary newbinary newempty rmempty rmbinary bintoregular; do > echo > echo '% git=auto: git diff for' $f > hg autodiff --git=auto $f > done % git=auto: git diff for exec diff -r a66d19b9302d exec --- a/exec +++ b/exec @@ -1,1 +1,2 @@ exec +exec % git=auto: git diff for newexec diff --git a/newexec b/newexec new file mode 100755 --- /dev/null +++ b/newexec @@ -0,0 +1,1 @@ +newexec % git=auto: git diff for setexec diff --git a/setexec b/setexec old mode 100644 new mode 100755 % git=auto: git diff for unsetexec diff --git a/unsetexec b/unsetexec old mode 100755 new mode 100644 % git=auto: git diff for binary diff --git a/binary b/binary index a9128c283485202893f5af379dd9beccb6e79486..09f370e38f498a462e1ca0faa724559b6630c04f GIT binary patch literal 2 Jc${Nk0000200961 % git=auto: git diff for newbinary diff --git a/newbinary b/newbinary new file mode 100644 index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..f76dd238ade08917e6712764a16a22005a50573d GIT binary patch literal 1 Ic${MZ000310RR91 % git=auto: git diff for newempty diff --git a/newempty b/newempty new file mode 100644 % git=auto: git diff for rmempty diff --git a/rmempty b/rmempty deleted file mode 100644 % git=auto: git diff for rmbinary diff --git a/rmbinary b/rmbinary deleted file mode 100644 index f76dd238ade08917e6712764a16a22005a50573d..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 GIT binary patch literal 0 Hc$@<O00001 % git=auto: git diff for bintoregular diff --git a/bintoregular b/bintoregular index f76dd238ade08917e6712764a16a22005a50573d..9c42f2b6427d8bf034b7bc23986152dc01bfd3ab GIT binary patch literal 13 Uc$`bh%qz(+N=+}#Ni5<5043uE82|tP git=warn: regular diff with data loss warnings $ hg autodiff --git=warn diff -r a66d19b9302d binary Binary file binary has changed diff -r a66d19b9302d bintoregular Binary file bintoregular has changed diff -r a66d19b9302d exec --- a/exec +++ b/exec @@ -1,1 +1,2 @@ exec +exec diff -r a66d19b9302d newbinary Binary file newbinary has changed diff -r a66d19b9302d newexec --- /dev/null +++ b/newexec @@ -0,0 +1,1 @@ +newexec diff -r a66d19b9302d newregular --- /dev/null +++ b/newregular @@ -0,0 +1,1 @@ +newregular diff -r a66d19b9302d regular --- a/regular +++ b/regular @@ -1,1 +1,2 @@ regular +regular diff -r a66d19b9302d rmbinary Binary file rmbinary has changed diff -r a66d19b9302d rmexec --- a/rmexec +++ /dev/null @@ -1,1 +0,0 @@ -rmexec diff -r a66d19b9302d rmregular --- a/rmregular +++ /dev/null @@ -1,1 +0,0 @@ -rmregular data lost for: binary data lost for: bintoregular data lost for: newbinary data lost for: newempty data lost for: newexec data lost for: rmbinary data lost for: rmempty data lost for: setexec data lost for: unsetexec git=abort: fail on execute bit change $ hg autodiff --git=abort regular setexec abort: losing data for setexec [255] git=abort: succeed on regular file $ hg autodiff --git=abort regular diff -r a66d19b9302d regular --- a/regular +++ b/regular @@ -1,1 +1,2 @@ regular +regular $ cd ..