localrepo: create new function for instantiating a local repo object
Today, there is a single local repository class - localrepository. Its
__init__ is responsible for loading the .hg/requires file and taking
different actions depending on what is present.
In addition, extensions may define a "reposetup" function that
monkeypatches constructed repository instances, often by implementing
a derived type and changing the __class__ of the repo instance.
Work around alternate storage backends and partial clone has made it
clear to me that shoehorning all this logic into __init__ and operating
on an existing instance is too convoluted. For example, localrepository
assumes revlog storage and swapping in non-revlog storage requires
overriding e.g. file() to return something that isn't a revlog. I've
authored various patches that either:
a) teach various methods (like file()) about different states and
taking the appropriate code path at run-time
b) create methods/attributes/callables used for instantiating things
and populating these in __init__
"a" incurs run-time performance penalties and makes code more
complicated since various functions have a bunch of "if storage is X"
branches.
"b" makes localrepository quickly explode in complexity.
My plan for tackling this problem is to make the local repository type
more dynamic. Instead of a static localrepository class/type that
supports all of the local repository configurations (revlogs vs other,
revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll
dynamically construct a type providing the implementations that are
needed for the repository on disk, derived from the .hg/requires file
and configuration options. The constructed repository type will be
specialized and methods won't need to be taught about different
implementations nor overloaded.
We may also leverage this functionality for building types that don't
implement all attributes. For example, the "intents" feature allows
commands to declare that they are read only. By dynamically
constructing a repository type, we could return a repository instance
with no attributes related to mutating the repository. This could
include things like a "changelog" property implementation that doesn't
check whether it needs to invalidate the hidden revisions set on every
access.
This commit establishes a function for building a local repository
instance. Future commits will start moving functionality from
localrepository.__init__ to this function. Then we'll start dynamically
changing the returned type depending on options that are present.
This change may seem radical. But it should be fully compatible with
the reposetup() model - at least for now.
Differential Revision: https://phab.mercurial-scm.org/D4563
Create @ bookmark as main reference
$ hg init repo
$ cd repo
$ echo "[extensions]" >> $HGRCPATH
$ echo "patchbomb=" >> $HGRCPATH
$ hg book @
Create a dummy revision that must never be exported
$ echo no > no
$ hg ci -Amno -d '6 0'
adding no
Create a feature and use -B
$ hg book booktest
$ echo first > a
$ hg ci -Amfirst -d '7 0'
adding a
$ echo second > b
$ hg ci -Amsecond -d '8 0'
adding b
$ hg email --date '1981-1-1 0:1' -n -t foo -s bookmark -B booktest
From [test]: test
this patch series consists of 2 patches.
Write the introductory message for the patch series.
Cc:
displaying [PATCH 0 of 2] bookmark ...
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
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Subject: [PATCH 0 of 2] bookmark
Message-Id: <patchbomb.347155260@test-hostname>
User-Agent: Mercurial-patchbomb/* (glob)
Date: Thu, 01 Jan 1981 00:01:00 +0000
From: test
To: foo
displaying [PATCH 1 of 2] first ...
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Subject: [PATCH 1 of 2] first
X-Mercurial-Node: accde9b8b6dce861c185d0825c1affc09a79cb26
X-Mercurial-Series-Index: 1
X-Mercurial-Series-Total: 2
Message-Id: <accde9b8b6dce861c185.347155261@test-hostname>
X-Mercurial-Series-Id: <accde9b8b6dce861c185.347155261@test-hostname>
In-Reply-To: <patchbomb.347155260@test-hostname>
References: <patchbomb.347155260@test-hostname>
User-Agent: Mercurial-patchbomb/* (glob)
Date: Thu, 01 Jan 1981 00:01:01 +0000
From: test
To: foo
# HG changeset patch
# User test
# Date 7 0
# Thu Jan 01 00:00:07 1970 +0000
# Node ID accde9b8b6dce861c185d0825c1affc09a79cb26
# Parent 043bd3889e5aaf7d88fe3713cf425f782ad2fb71
first
diff -r 043bd3889e5a -r accde9b8b6dc a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:07 1970 +0000
@@ -0,0 +1,1 @@
+first
displaying [PATCH 2 of 2] second ...
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X-Mercurial-Series-Index: 2
X-Mercurial-Series-Total: 2
Message-Id: <417defd1559c396ba06a.347155262@test-hostname>
X-Mercurial-Series-Id: <accde9b8b6dce861c185.347155261@test-hostname>
In-Reply-To: <patchbomb.347155260@test-hostname>
References: <patchbomb.347155260@test-hostname>
User-Agent: Mercurial-patchbomb/* (glob)
Date: Thu, 01 Jan 1981 00:01:02 +0000
From: test
To: foo
# HG changeset patch
# User test
# Date 8 0
# Thu Jan 01 00:00:08 1970 +0000
# Node ID 417defd1559c396ba06a44dce8dc1c2d2d653f3f
# Parent accde9b8b6dce861c185d0825c1affc09a79cb26
second
diff -r accde9b8b6dc -r 417defd1559c b
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/b Thu Jan 01 00:00:08 1970 +0000
@@ -0,0 +1,1 @@
+second
Do the same and combine with -o only one must be exported
$ cd ..
$ hg clone repo repo2
updating to bookmark @
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo
$ hg up @
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
(activating bookmark @)
$ hg book outgoing
$ echo 1 > x
$ hg ci -Am1 -d '8 0'
adding x
created new head
$ hg push ../repo2 -B outgoing
pushing to ../repo2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
exporting bookmark outgoing
$ echo 2 > y
$ hg ci -Am2 -d '9 0'
adding y
$ hg email --date '1982-1-1 0:1' -n -t foo -s bookmark -B outgoing -o ../repo2
comparing with ../repo2
From [test]: test
this patch series consists of 1 patches.
Cc:
displaying [PATCH] bookmark ...
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Subject: [PATCH] bookmark
X-Mercurial-Node: 8dab2639fd35f1e337ad866c372a5c44f1064e3c
X-Mercurial-Series-Index: 1
X-Mercurial-Series-Total: 1
Message-Id: <8dab2639fd35f1e337ad.378691260@test-hostname>
X-Mercurial-Series-Id: <8dab2639fd35f1e337ad.378691260@test-hostname>
User-Agent: Mercurial-patchbomb/* (glob)
Date: Fri, 01 Jan 1982 00:01:00 +0000
From: test
To: foo
# HG changeset patch
# User test
# Date 9 0
# Thu Jan 01 00:00:09 1970 +0000
# Node ID 8dab2639fd35f1e337ad866c372a5c44f1064e3c
# Parent 0b24b8316483bf30bfc3e4d4168e922b169dbe66
2
diff -r 0b24b8316483 -r 8dab2639fd35 y
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/y Thu Jan 01 00:00:09 1970 +0000
@@ -0,0 +1,1 @@
+2