[PATCH 1 of 5] transaction: introduce scope

Jun Wu quark at fb.com
Wed Mar 1 23:48:33 EST 2017


I'm going to drop this series from patchwork. The new dirstate patches is a
better fix.

Excerpts from Jun Wu's message of 2017-02-27 09:35:25 -0800:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1488185788 28800
> #      Mon Feb 27 00:56:28 2017 -0800
> # Node ID 5dac612ec9a87553fcd329100846bcb01bae9d80
> # Parent  b4cb86ab4c719eb615a4308eafd8b1386a511eeb
> # Available At https://bitbucket.org/quark-zju/hg-draft 
> #              hg pull https://bitbucket.org/quark-zju/hg-draft  -r 5dac612ec9a8
> transaction: introduce scope
> 
> Previously, transaction tries to cover everything: bookmarks, dirstate,
> phaseroots, and branch. It backs them up unconditionally.
> 
> That could be inefficient if we still back up the dirstate in a giant repo,
> where the transaction is only intended to change bookmarks.
> 
> This patch introduces "scope" to transactions, which is a set of things that
> the transaction should cover. For bookmark-only update, it could avoid
> specifying the "dirstate" scope to be more efficient.
> 
> diff --git a/mercurial/transaction.py b/mercurial/transaction.py
> --- a/mercurial/transaction.py
> +++ b/mercurial/transaction.py
> @@ -102,5 +102,6 @@ def _playback(journal, report, opener, v
>  class transaction(object):
>      def __init__(self, report, opener, vfsmap, journalname, undoname=None,
> -                 after=None, createmode=None, validator=None, releasefn=None):
> +                 after=None, createmode=None, validator=None, releasefn=None,
> +                 scope=None):
>          """Begin a new transaction
>  
> @@ -111,4 +112,5 @@ class transaction(object):
>          * `createmode`: the mode of the journal file that will be created
>          * `releasefn`: called after releasing (with transaction and result)
> +        * `scope`: a set-like, nested transaction's scope must be a subset
>          """
>          self.count = 1
> @@ -171,4 +173,7 @@ class transaction(object):
>          self._abortcallback = {}
>  
> +        # a set indicating what's covered
> +        self._scope = scope or frozenset()
> +
>      def __del__(self):
>          if self.journal:
> @@ -342,5 +347,10 @@ class transaction(object):
>  
>      @active
> -    def nest(self):
> +    def nest(self, scope=None):
> +        scope = scope or frozenset()
> +        if not scope.issubset(self._scope):
> +            raise error.ProgrammingError(
> +                'nested transaction has a superset scope (%s > %s)'
> +                % (scope, self._scope))
>          self.count += 1
>          self.usages += 1
> @@ -555,4 +565,7 @@ class transaction(object):
>              self.releasefn(self, False) # notify failure of transaction
>  
> +    def scope(self):
> +        return self._scope
> +
>  def rollback(opener, vfsmap, file, report):
>      """Rolls back the transaction contained in the given file


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