From a4e3bc61bcb1f1aeaa334f6da4f3b9fcb3059d00 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 5 Feb 2012 14:22:55 -0500 Subject: - [bug] A significant change to how labeling is applied to columns in SELECT statements allows "truncated" labels, that is label names that are generated in Python which exceed the maximum identifier length (note this is configurable via label_length on create_engine()), to be properly referenced when rendered inside of a subquery, as well as to be present in a result set row using their original in-Python names. [ticket:2396] - apply pep8 to test_labels --- lib/sqlalchemy/sql/expression.py | 74 +++++++++++++++++++++++++++++----------- 1 file changed, 54 insertions(+), 20 deletions(-) (limited to 'lib/sqlalchemy/sql/expression.py') diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 859ee0437..939456b9a 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -1283,14 +1283,48 @@ func = _FunctionGenerator() # TODO: use UnaryExpression for this instead ? modifier = _FunctionGenerator(group=False) -class _generated_label(unicode): - """A unicode subclass used to identify dynamically generated names.""" +class _truncated_label(unicode): + """A unicode subclass used to identify symbolic " + "names that may require truncation.""" -def _escape_for_generated(x): - if isinstance(x, _generated_label): - return x + def apply_map(self, map_): + return self + +# for backwards compatibility in case +# someone is re-implementing the +# _truncated_identifier() sequence in a custom +# compiler +_generated_label = _truncated_label + +class _anonymous_label(_truncated_label): + """A unicode subclass used to identify anonymously + generated names.""" + + def __add__(self, other): + return _anonymous_label( + unicode(self) + + unicode(other)) + + def __radd__(self, other): + return _anonymous_label( + unicode(other) + + unicode(self)) + + def apply_map(self, map_): + return self % map_ + +def _as_truncated(value): + """coerce the given value to :class:`._truncated_label`. + + Existing :class:`._truncated_label` and + :class:`._anonymous_label` objects are passed + unchanged. + """ + + if isinstance(value, _truncated_label): + return value else: - return x.replace('%', '%%') + return _truncated_label(value) def _string_or_unprintable(element): if isinstance(element, basestring): @@ -2117,7 +2151,9 @@ class ColumnElement(ClauseElement, _CompareMixin): else: key = name - co = ColumnClause(name, selectable, type_=getattr(self, + co = ColumnClause(_as_truncated(name), + selectable, + type_=getattr(self, 'type', None)) co.proxies = [self] selectable._columns[key] = co @@ -2165,7 +2201,7 @@ class ColumnElement(ClauseElement, _CompareMixin): expressions and function calls. """ - return _generated_label('%%(%d %s)s' % (id(self), getattr(self, + return _anonymous_label('%%(%d %s)s' % (id(self), getattr(self, 'name', 'anon'))) class ColumnCollection(util.OrderedProperties): @@ -2588,10 +2624,10 @@ class _BindParamClause(ColumnElement): """ if unique: - self.key = _generated_label('%%(%d %s)s' % (id(self), key + self.key = _anonymous_label('%%(%d %s)s' % (id(self), key or 'param')) else: - self.key = key or _generated_label('%%(%d param)s' + self.key = key or _anonymous_label('%%(%d param)s' % id(self)) # identifiying key that won't change across @@ -2639,14 +2675,14 @@ class _BindParamClause(ColumnElement): def _clone(self): c = ClauseElement._clone(self) if self.unique: - c.key = _generated_label('%%(%d %s)s' % (id(c), c._orig_key + c.key = _anonymous_label('%%(%d %s)s' % (id(c), c._orig_key or 'param')) return c def _convert_to_unique(self): if not self.unique: self.unique = True - self.key = _generated_label('%%(%d %s)s' % (id(self), + self.key = _anonymous_label('%%(%d %s)s' % (id(self), self._orig_key or 'param')) def compare(self, other, **kw): @@ -3615,7 +3651,7 @@ class Alias(FromClause): if name is None: if self.original.named_with_column: name = getattr(self.original, 'name', None) - name = _generated_label('%%(%d %s)s' % (id(self), name + name = _anonymous_label('%%(%d %s)s' % (id(self), name or 'anon')) self.name = name @@ -3816,7 +3852,7 @@ class _Label(ColumnElement): while isinstance(element, _Label): element = element.element self.name = self.key = self._label = name \ - or _generated_label('%%(%d %s)s' % (id(self), + or _anonymous_label('%%(%d %s)s' % (id(self), getattr(element, 'name', 'anon'))) self._element = element self._type = type_ @@ -3973,11 +4009,9 @@ class ColumnClause(_Immutable, ColumnElement): elif t is not None and t.named_with_column: if getattr(t, 'schema', None): label = t.schema.replace('.', '_') + "_" + \ - _escape_for_generated(t.name) + "_" + \ - _escape_for_generated(self.name) + t.name + "_" + self.name else: - label = _escape_for_generated(t.name) + "_" + \ - _escape_for_generated(self.name) + label = t.name + "_" + self.name # ensure the label name doesn't conflict with that # of an existing column @@ -3989,7 +4023,7 @@ class ColumnClause(_Immutable, ColumnElement): counter += 1 label = _label - return _generated_label(label) + return _as_truncated(label) else: return self.name @@ -4018,7 +4052,7 @@ class ColumnClause(_Immutable, ColumnElement): # otherwise its considered to be a label is_literal = self.is_literal and (name is None or name == self.name) c = self._constructor( - name or self.name, + _as_truncated(name or self.name), selectable=selectable, type_=self.type, is_literal=is_literal -- cgit v1.2.1