0x1998 - MANAGER

Düzenlenen Dosya: revision.py

import re import collections from .. import util from sqlalchemy import util as sqlautil from ..util import compat _relative_destination = re.compile(r'(?:(.+?)@)?(\w+)?((?:\+|-)\d+)') class RevisionError(Exception): pass class RangeNotAncestorError(RevisionError): def __init__(self, lower, upper): self.lower = lower self.upper = upper super(RangeNotAncestorError, self).__init__( "Revision %s is not an ancestor of revision %s" % (lower or "base", upper or "base") ) class MultipleHeads(RevisionError): def __init__(self, heads, argument): self.heads = heads self.argument = argument super(MultipleHeads, self).__init__( "Multiple heads are present for given argument '%s'; " "%s" % (argument, ", ".join(heads)) ) class ResolutionError(RevisionError): def __init__(self, message, argument): super(ResolutionError, self).__init__(message) self.argument = argument class RevisionMap(object): """Maintains a map of :class:`.Revision` objects. :class:`.RevisionMap` is used by :class:`.ScriptDirectory` to maintain and traverse the collection of :class:`.Script` objects, which are themselves instances of :class:`.Revision`. """ def __init__(self, generator): """Construct a new :class:`.RevisionMap`. :param generator: a zero-arg callable that will generate an iterable of :class:`.Revision` instances to be used. These are typically :class:`.Script` subclasses within regular Alembic use. """ self._generator = generator @util.memoized_property def heads(self): """All "head" revisions as strings. This is normally a tuple of length one, unless unmerged branches are present. :return: a tuple of string revision numbers. """ self._revision_map return self.heads @util.memoized_property def bases(self): """All "base" revisions as strings. These are revisions that have a ``down_revision`` of None, or empty tuple. :return: a tuple of string revision numbers. """ self._revision_map return self.bases @util.memoized_property def _real_heads(self): """All "real" head revisions as strings. :return: a tuple of string revision numbers. """ self._revision_map return self._real_heads @util.memoized_property def _real_bases(self): """All "real" base revisions as strings. :return: a tuple of string revision numbers. """ self._revision_map return self._real_bases @util.memoized_property def _revision_map(self): """memoized attribute, initializes the revision map from the initial collection. """ map_ = {} heads = sqlautil.OrderedSet() _real_heads = sqlautil.OrderedSet() self.bases = () self._real_bases = () has_branch_labels = set() has_depends_on = set() for revision in self._generator(): if revision.revision in map_: util.warn("Revision %s is present more than once" % revision.revision) map_[revision.revision] = revision if revision.branch_labels: has_branch_labels.add(revision) if revision.dependencies: has_depends_on.add(revision) heads.add(revision.revision) _real_heads.add(revision.revision) if revision.is_base: self.bases += (revision.revision, ) if revision._is_real_base: self._real_bases += (revision.revision, ) # add the branch_labels to the map_. We'll need these # to resolve the dependencies. for revision in has_branch_labels: self._map_branch_labels(revision, map_) for revision in has_depends_on: self._add_depends_on(revision, map_) for rev in map_.values(): for downrev in rev._all_down_revisions: if downrev not in map_: util.warn("Revision %s referenced from %s is not present" % (downrev, rev)) down_revision = map_[downrev] down_revision.add_nextrev(rev) if downrev in rev._versioned_down_revisions: heads.discard(downrev) _real_heads.discard(downrev) map_[None] = map_[()] = None self.heads = tuple(heads) self._real_heads = tuple(_real_heads) for revision in has_branch_labels: self._add_branches(revision, map_, map_branch_labels=False) return map_ def _map_branch_labels(self, revision, map_): if revision.branch_labels: for branch_label in revision._orig_branch_labels: if branch_label in map_: raise RevisionError( "Branch name '%s' in revision %s already " "used by revision %s" % (branch_label, revision.revision, map_[branch_label].revision) ) map_[branch_label] = revision def _add_branches(self, revision, map_, map_branch_labels=True): if map_branch_labels: self._map_branch_labels(revision, map_) if revision.branch_labels: revision.branch_labels.update(revision.branch_labels) for node in self._get_descendant_nodes( [revision], map_, include_dependencies=False): node.branch_labels.update(revision.branch_labels) parent = node while parent and \ not parent._is_real_branch_point and \ not parent.is_merge_point: parent.branch_labels.update(revision.branch_labels) if parent.down_revision: parent = map_[parent.down_revision] else: break def _add_depends_on(self, revision, map_): if revision.dependencies: revision._resolved_dependencies = tuple( map_[dep].revision for dep in util.to_tuple(revision.dependencies) ) def add_revision(self, revision, _replace=False): """add a single revision to an existing map. This method is for single-revision use cases, it's not appropriate for fully populating an entire revision map. """ map_ = self._revision_map if not _replace and revision.revision in map_: util.warn("Revision %s is present more than once" % revision.revision) elif _replace and revision.revision not in map_: raise Exception("revision %s not in map" % revision.revision) map_[revision.revision] = revision self._add_branches(revision, map_) self._add_depends_on(revision, map_) if revision.is_base: self.bases += (revision.revision, ) if revision._is_real_base: self._real_bases += (revision.revision, ) for downrev in revision._all_down_revisions: if downrev not in map_: util.warn( "Revision %s referenced from %s is not present" % (downrev, revision) ) map_[downrev].add_nextrev(revision) if revision._is_real_head: self._real_heads = tuple( head for head in self._real_heads if head not in set(revision._all_down_revisions).union([revision.revision]) ) + (revision.revision,) if revision.is_head: self.heads = tuple( head for head in self.heads if head not in set(revision._versioned_down_revisions).union([revision.revision]) ) + (revision.revision,) def get_current_head(self, branch_label=None): """Return the current head revision. If the script directory has multiple heads due to branching, an error is raised; :meth:`.ScriptDirectory.get_heads` should be preferred. :param branch_label: optional branch name which will limit the heads considered to those which include that branch_label. :return: a string revision number. .. seealso:: :meth:`.ScriptDirectory.get_heads` """ current_heads = self.heads if branch_label: current_heads = self.filter_for_lineage(current_heads, branch_label) if len(current_heads) > 1: raise MultipleHeads( current_heads, "%s@head" % branch_label if branch_label else "head") if current_heads: return current_heads[0] else: return None def _get_base_revisions(self, identifier): return self.filter_for_lineage(self.bases, identifier) def get_revisions(self, id_): """Return the :class:`.Revision` instances with the given rev id or identifiers. May be given a single identifier, a sequence of identifiers, or the special symbols "head" or "base". The result is a tuple of one or more identifiers, or an empty tuple in the case of "base". In the cases where 'head', 'heads' is requested and the revision map is empty, returns an empty tuple. Supports partial identifiers, where the given identifier is matched against all identifiers that start with the given characters; if there is exactly one match, that determines the full revision. """ if isinstance(id_, (list, tuple, set, frozenset)): return sum([self.get_revisions(id_elem) for id_elem in id_], ()) else: resolved_id, branch_label = self._resolve_revision_number(id_) return tuple( self._revision_for_ident(rev_id, branch_label) for rev_id in resolved_id) def get_revision(self, id_): """Return the :class:`.Revision` instance with the given rev id. If a symbolic name such as "head" or "base" is given, resolves the identifier into the current head or base revision. If the symbolic name refers to multiples, :class:`.MultipleHeads` is raised. Supports partial identifiers, where the given identifier is matched against all identifiers that start with the given characters; if there is exactly one match, that determines the full revision. """ resolved_id, branch_label = self._resolve_revision_number(id_) if len(resolved_id) > 1: raise MultipleHeads(resolved_id, id_) elif resolved_id: resolved_id = resolved_id[0] return self._revision_for_ident(resolved_id, branch_label) def _resolve_branch(self, branch_label): try: branch_rev = self._revision_map[branch_label] except KeyError: try: nonbranch_rev = self._revision_for_ident(branch_label) except ResolutionError: raise ResolutionError( "No such branch: '%s'" % branch_label, branch_label) else: return nonbranch_rev else: return branch_rev def _revision_for_ident(self, resolved_id, check_branch=None): if check_branch: branch_rev = self._resolve_branch(check_branch) else: branch_rev = None try: revision = self._revision_map[resolved_id] except KeyError: # do a partial lookup revs = [x for x in self._revision_map if x and x.startswith(resolved_id)] if branch_rev: revs = self.filter_for_lineage(revs, check_branch) if not revs: raise ResolutionError( "No such revision or branch '%s'" % resolved_id, resolved_id) elif len(revs) > 1: raise ResolutionError( "Multiple revisions start " "with '%s': %s..." % ( resolved_id, ", ".join("'%s'" % r for r in revs[0:3]) ), resolved_id) else: revision = self._revision_map[revs[0]] if check_branch and revision is not None: if not self._shares_lineage( revision.revision, branch_rev.revision): raise ResolutionError( "Revision %s is not a member of branch '%s'" % (revision.revision, check_branch), resolved_id) return revision def filter_for_lineage( self, targets, check_against, include_dependencies=False): id_, branch_label = self._resolve_revision_number(check_against) shares = [] if branch_label: shares.append(branch_label) if id_: shares.extend(id_) return [ tg for tg in targets if self._shares_lineage( tg, shares, include_dependencies=include_dependencies)] def _shares_lineage( self, target, test_against_revs, include_dependencies=False): if not test_against_revs: return True if not isinstance(target, Revision): target = self._revision_for_ident(target) test_against_revs = [ self._revision_for_ident(test_against_rev) if not isinstance(test_against_rev, Revision) else test_against_rev for test_against_rev in util.to_tuple(test_against_revs, default=()) ] return bool( set(self._get_descendant_nodes([target], include_dependencies=include_dependencies)) .union(self._get_ancestor_nodes([target], include_dependencies=include_dependencies)) .intersection(test_against_revs) ) def _resolve_revision_number(self, id_): if isinstance(id_, compat.string_types) and "@" in id_: branch_label, id_ = id_.split('@', 1) else: branch_label = None # ensure map is loaded self._revision_map if id_ == 'heads': if branch_label: return self.filter_for_lineage( self.heads, branch_label), branch_label else: return self._real_heads, branch_label elif id_ == 'head': current_head = self.get_current_head(branch_label) if current_head: return (current_head, ), branch_label else: return (), branch_label elif id_ == 'base' or id_ is None: return (), branch_label else: return util.to_tuple(id_, default=None), branch_label def _relative_iterate( self, destination, source, is_upwards, implicit_base, inclusive, assert_relative_length): if isinstance(destination, compat.string_types): match = _relative_destination.match(destination) if not match: return None else: return None relative = int(match.group(3)) symbol = match.group(2) branch_label = match.group(1) reldelta = 1 if inclusive and not symbol else 0 if is_upwards: if branch_label: from_ = "%s@head" % branch_label elif symbol: if symbol.startswith("head"): from_ = symbol else: from_ = "%s@head" % symbol else: from_ = "head" to_ = source else: if branch_label: to_ = "%s@base" % branch_label elif symbol: to_ = "%s@base" % symbol else: to_ = "base" from_ = source revs = list( self._iterate_revisions( from_, to_, inclusive=inclusive, implicit_base=implicit_base)) if symbol: if branch_label: symbol_rev = self.get_revision( "%s@%s" % (branch_label, symbol)) else: symbol_rev = self.get_revision(symbol) if symbol.startswith("head"): index = 0 elif symbol == "base": index = len(revs) - 1 else: range_ = compat.range(len(revs) - 1, 0, -1) for index in range_: if symbol_rev.revision == revs[index].revision: break else: index = 0 else: index = 0 if is_upwards: revs = revs[index - relative - reldelta:] if not index and assert_relative_length and \ len(revs) < abs(relative - reldelta): raise RevisionError( "Relative revision %s didn't " "produce %d migrations" % (destination, abs(relative))) else: revs = revs[0:index - relative + reldelta] if not index and assert_relative_length and \ len(revs) != abs(relative) + reldelta: raise RevisionError( "Relative revision %s didn't " "produce %d migrations" % (destination, abs(relative))) return iter(revs) def iterate_revisions( self, upper, lower, implicit_base=False, inclusive=False, assert_relative_length=True): """Iterate through script revisions, starting at the given upper revision identifier and ending at the lower. The traversal uses strictly the `down_revision` marker inside each migration script, so it is a requirement that upper >= lower, else you'll get nothing back. The iterator yields :class:`.Revision` objects. """ relative_upper = self._relative_iterate( upper, lower, True, implicit_base, inclusive, assert_relative_length ) if relative_upper: return relative_upper relative_lower = self._relative_iterate( lower, upper, False, implicit_base, inclusive, assert_relative_length ) if relative_lower: return relative_lower return self._iterate_revisions( upper, lower, inclusive=inclusive, implicit_base=implicit_base) def _get_descendant_nodes( self, targets, map_=None, check=False, include_dependencies=True): if include_dependencies: fn = lambda rev: rev._all_nextrev else: fn = lambda rev: rev.nextrev return self._iterate_related_revisions( fn, targets, map_=map_, check=check ) def _get_ancestor_nodes( self, targets, map_=None, check=False, include_dependencies=True): if include_dependencies: fn = lambda rev: rev._all_down_revisions else: fn = lambda rev: rev._versioned_down_revisions return self._iterate_related_revisions( fn, targets, map_=map_, check=check ) def _iterate_related_revisions(self, fn, targets, map_, check=False): if map_ is None: map_ = self._revision_map seen = set() todo = collections.deque() for target in targets: todo.append(target) if check: per_target = set() while todo: rev = todo.pop() if check: per_target.add(rev) if rev in seen: continue seen.add(rev) todo.extend( map_[rev_id] for rev_id in fn(rev)) yield rev if check and per_target.intersection(targets).difference([target]): raise RevisionError( "Requested revision %s overlaps with " "other requested revisions" % target.revision) def _iterate_revisions( self, upper, lower, inclusive=True, implicit_base=False): """iterate revisions from upper to lower. The traversal is depth-first within branches, and breadth-first across branches as a whole. """ requested_lowers = self.get_revisions(lower) # some complexity to accommodate an iteration where some # branches are starting from nothing, and others are starting # from a given point. Additionally, if the bottom branch # is specified using a branch identifier, then we limit operations # to just that branch. limit_to_lower_branch = \ isinstance(lower, compat.string_types) and lower.endswith('@base') uppers = util.dedupe_tuple(self.get_revisions(upper)) if not uppers and not requested_lowers: raise StopIteration() upper_ancestors = set(self._get_ancestor_nodes(uppers, check=True)) if limit_to_lower_branch: lowers = self.get_revisions(self._get_base_revisions(lower)) elif implicit_base and requested_lowers: lower_ancestors = set( self._get_ancestor_nodes(requested_lowers) ) lower_descendants = set( self._get_descendant_nodes(requested_lowers) ) base_lowers = set() candidate_lowers = upper_ancestors.\ difference(lower_ancestors).\ difference(lower_descendants) for rev in candidate_lowers: for downrev in rev._all_down_revisions: if self._revision_map[downrev] in candidate_lowers: break else: base_lowers.add(rev) lowers = base_lowers.union(requested_lowers) elif implicit_base: base_lowers = set(self.get_revisions(self._real_bases)) lowers = base_lowers.union(requested_lowers) elif not requested_lowers: lowers = set(self.get_revisions(self._real_bases)) else: lowers = requested_lowers # represents all nodes we will produce total_space = set( rev.revision for rev in upper_ancestors).intersection( rev.revision for rev in self._get_descendant_nodes(lowers, check=True) ) if not total_space: raise RangeNotAncestorError(lower, upper) # organize branch points to be consumed separately from # member nodes branch_todo = set( rev for rev in (self._revision_map[rev] for rev in total_space) if rev._is_real_branch_point and len(total_space.intersection(rev._all_nextrev)) > 1 ) # it's not possible for any "uppers" to be in branch_todo, # because the ._all_nextrev of those nodes is not in total_space #assert not branch_todo.intersection(uppers) todo = collections.deque( r for r in uppers if r.revision in total_space) # iterate for total_space being emptied out total_space_modified = True while total_space: if not total_space_modified: raise RevisionError( "Dependency resolution failed; iteration can't proceed") total_space_modified = False # when everything non-branch pending is consumed, # add to the todo any branch nodes that have no # descendants left in the queue if not todo: todo.extendleft( sorted( ( rev for rev in branch_todo if not rev._all_nextrev.intersection(total_space) ), # favor "revisioned" branch points before # dependent ones key=lambda rev: 0 if rev.is_branch_point else 1 ) ) branch_todo.difference_update(todo) # iterate nodes that are in the immediate todo while todo: rev = todo.popleft() total_space.remove(rev.revision) total_space_modified = True # do depth first for elements within branches, # don't consume any actual branch nodes todo.extendleft([ self._revision_map[downrev] for downrev in reversed(rev._all_down_revisions) if self._revision_map[downrev] not in branch_todo and downrev in total_space]) if not inclusive and rev in requested_lowers: continue yield rev assert not branch_todo class Revision(object): """Base class for revisioned objects. The :class:`.Revision` class is the base of the more public-facing :class:`.Script` object, which represents a migration script. The mechanics of revision management and traversal are encapsulated within :class:`.Revision`, while :class:`.Script` applies this logic to Python files in a version directory. """ nextrev = frozenset() """following revisions, based on down_revision only.""" _all_nextrev = frozenset() revision = None """The string revision number.""" down_revision = None """The ``down_revision`` identifier(s) within the migration script. Note that the total set of "down" revisions is down_revision + dependencies. """ dependencies = None """Additional revisions which this revision is dependent on. From a migration standpoint, these dependencies are added to the down_revision to form the full iteration. However, the separation of down_revision from "dependencies" is to assist in navigating a history that contains many branches, typically a multi-root scenario. """ branch_labels = None """Optional string/tuple of symbolic names to apply to this revision's branch""" def __init__( self, revision, down_revision, dependencies=None, branch_labels=None): self.revision = revision self.down_revision = tuple_rev_as_scalar(down_revision) self.dependencies = tuple_rev_as_scalar(dependencies) self._resolved_dependencies = () self._orig_branch_labels = util.to_tuple(branch_labels, default=()) self.branch_labels = set(self._orig_branch_labels) def __repr__(self): args = [ repr(self.revision), repr(self.down_revision) ] if self.dependencies: args.append("dependencies=%r" % self.dependencies) if self.branch_labels: args.append("branch_labels=%r" % self.branch_labels) return "%s(%s)" % ( self.__class__.__name__, ", ".join(args) ) def add_nextrev(self, revision): self._all_nextrev = self._all_nextrev.union([revision.revision]) if self.revision in revision._versioned_down_revisions: self.nextrev = self.nextrev.union([revision.revision]) @property def _all_down_revisions(self): return util.to_tuple(self.down_revision, default=()) + \ self._resolved_dependencies @property def _versioned_down_revisions(self): return util.to_tuple(self.down_revision, default=()) @property def is_head(self): """Return True if this :class:`.Revision` is a 'head' revision. This is determined based on whether any other :class:`.Script` within the :class:`.ScriptDirectory` refers to this :class:`.Script`. Multiple heads can be present. """ return not bool(self.nextrev) @property def _is_real_head(self): return not bool(self._all_nextrev) @property def is_base(self): """Return True if this :class:`.Revision` is a 'base' revision.""" return self.down_revision is None @property def _is_real_base(self): """Return True if this :class:`.Revision` is a "real" base revision, e.g. that it has no dependencies either.""" # we use self.dependencies here because this is called up # in initialization where _real_dependencies isn't set up # yet return self.down_revision is None and self.dependencies is None @property def is_branch_point(self): """Return True if this :class:`.Script` is a branch point. A branchpoint is defined as a :class:`.Script` which is referred to by more than one succeeding :class:`.Script`, that is more than one :class:`.Script` has a `down_revision` identifier pointing here. """ return len(self.nextrev) > 1 @property def _is_real_branch_point(self): """Return True if this :class:`.Script` is a 'real' branch point, taking into account dependencies as well. """ return len(self._all_nextrev) > 1 @property def is_merge_point(self): """Return True if this :class:`.Script` is a merge point.""" return len(self._versioned_down_revisions) > 1 def tuple_rev_as_scalar(rev): if not rev: return None elif len(rev) == 1: return rev[0] else: return rev
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