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outdated and unsupported repo format.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.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ echo "[diff]" >> $HGRCPATH
$ echo "nodates=true" >> $HGRCPATH
$ catlog() {
> cat .hg/patches/$1.patch | sed -e "s/^diff \-r [0-9a-f]* /diff -r ... /" \
> -e "s/^\(# Parent \).*/\1/"
> hg log --template "{rev}: {desc} - {author}\n"
> }
$ runtest() {
> echo ==== init
> hg init a
> cd a
> hg qinit
>
>
> echo ==== qnew -U
> hg qnew -U 1.patch
> catlog 1
>
> echo ==== qref
> echo "1" >1
> hg add
> hg qref
> catlog 1
>
> echo ==== qref -u
> hg qref -u mary
> catlog 1
>
> echo ==== qnew
> hg qnew 2.patch
> echo "2" >2
> hg add
> hg qref
> catlog 2
>
> echo ==== qref -u
> hg qref -u jane
> catlog 2
>
>
> echo ==== qnew -U -m
> hg qnew -U -m "Three" 3.patch
> catlog 3
>
> echo ==== qref
> echo "3" >3
> hg add
> hg qref
> catlog 3
>
> echo ==== qref -m
> hg qref -m "Drei"
> catlog 3
>
> echo ==== qref -u
> hg qref -u mary
> catlog 3
>
> echo ==== qref -u -m
> hg qref -u maria -m "Three (again)"
> catlog 3
>
> echo ==== qnew -m
> hg qnew -m "Four" 4.patch
> echo "4" >4of t
> hg add
> hg qref
> catlog 4
>
> echo ==== qref -u
> hg qref -u jane
> catlog 4
>
>
> echo ==== qnew with HG header
> hg qnew --config 'mq.plain=true' 5.patch
> hg qpop
> echo "# HG changeset patch" >>.hg/patches/5.patch
> echo "# User johndoe" >>.hg/patches/5.patch
> hg qpush 2>&1 | grep 'now at'
> catlog 5
>
> echo ==== hg qref
> echo "5" >5
> hg add
> hg qref
> catlog 5
>
> echo ==== hg qref -U
> hg qref -U
> catlog 5
>
> echo ==== hg qref -u
> hg qref -u johndeere
> catlog 5
>
>
> echo ==== qnew with plain header
> hg qnew --config 'mq.plain=true' -U 6.patch
> hg qpop
> hg qpush 2>&1 | grep 'now at'
> catlog 6
>
> echo ==== hg qref
> echo "6" >6
> hg add
> hg qref
> catlog 6
>
> echo ==== hg qref -U
> hg qref -U
> catlog 6
>
> echo ==== hg qref -u
> hg qref -u johndeere
> catlog 6
>
>
> echo ==== "qpop -a / qpush -a"
> hg qpop -a
> hg qpush -a
> hg log --template "{rev}: {desc} - {author}\n"
> }
======= plain headers
$ echo "[mq]" >> $HGRCPATH
$ echo "plain=true" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
==== init
==== qnew -U
From: test
0: [mq]: 1.patch - test
==== qref
adding 1
From: test
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
From: mary
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
From: jane
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
From: test
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
From: test
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
From: test
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
From: mary
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
From: maria
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
From: jane
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ rm -r sandbox
======= hg headers
$ echo "plain=false" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
==== init
==== qnew -U
# HG changeset patch
# User test
# Parent
0: [mq]: 1.patch - test
==== qref
adding 1
# HG changeset patch
# User test
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
# HG changeset patch
# User mary
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
# HG changeset patch
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
# HG changeset patch
# User test
# Parent
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
# HG changeset patch
# User test
# Parent
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
# HG changeset patch
# User test
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User mary
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
# HG changeset patch
# User maria
# Parent
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
# HG changeset patch
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ rm -r sandbox
$ runtest
==== init
==== qnew -U
# HG changeset patch
# User test
# Parent
0: [mq]: 1.patch - test
==== qref
adding 1
# HG changeset patch
# User test
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
# HG changeset patch
# User mary
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
# HG changeset patch
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
# HG changeset patch
# User test
# Parent
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
# HG changeset patch
# User test
# Parent
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
# HG changeset patch
# User test
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User mary
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
# HG changeset patch
# User maria
# Parent
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
# HG changeset patch
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ cd ..