8000 Do not close internally used cursors at all. · wulczer/txpostgres@7ecefe5 · GitHub
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Commit 7ecefe5

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wulczerwulczer
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Do not close internally used cursors at all.
The only reason for closing a psycopg2 cursor is to prevent its further usage. Cursors created internally when using runQuery and runOperation are never surfaced to the user, so there's no need to explicitly close them. Issue #35 spurred an effort to make sure all generated cursors are always closed, but it now seems that it's not the right way to go about the problem. There's no benefit to forcing psycopg2 cursors to be closed and if the cursor (or connection) are in a bad state, it risks throwing suprious errors. Leave it to psycopg2 to deal with cursors going away and simply fix runInteraction's docstring to explicitly say that the user should not close the cursor they got passed.
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‎NEWS

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Original file line numberDiff line numberDiff line change
@@ -1,3 +1,9 @@
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What's new in txpostgres 1.4.0
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------------------------------
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- internally used cursors are no longer explicitly closed, although
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it should not cause any user-visible changes
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17
What's new in txpostgres 1.3.0
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------------------------------
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‎test/test_txpostgres.py

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@@ -643,18 +643,14 @@ def test_runErrorInteraction(self):
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Interactions that produce errors are rolled back and the correct error
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is reported.
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"""
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keepCursor = []
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def interaction(c):
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keepCursor.append(c)
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d = c.execute("insert into simple values (1)")
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return d.addCallback(
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lambda c: c.execute("select * from nope_not_here"))
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d = self.conn.runInteraction(interaction)
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d = self.assertFailure(d, psycopg2.ProgrammingError)
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d.addCallback(lambda _: self.assertTrue(keepCursor[0].closed))
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d.addCallback(lambda _: self.conn.runQuery(
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"select count(*) from simple"))
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return d.addCallback(self.assertEquals, [(0, )])
@@ -665,10 +661,7 @@ def test_errorOnRollback(self):
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L{txpostgres.RollbackFailed} failure that has references to the faulty
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connection and the original failure that cause all that trouble.
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"""
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keepCursor = []
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def interaction(c):
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keepCursor.append(c)
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d = c.execute("insert into simple values (1)")
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return d.addCallback(
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lambda c: c.execute("select * from nope_not_here"))
@@ -691,7 +684,6 @@ def checkError(f):
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errors = self.flushLoggedErrors()
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self.assertEquals(len(errors), 1)
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self.assertEquals(errors[0].value.args[0], "boom")
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self.assertTrue(keepCursor[0].closed)
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# restore or we won't be able to clean up the mess
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mp.restore()
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d.addErrback(checkError)

‎txpostgres/txpostgres.py

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Original file line numberDiff line numberDiff line change
@@ -517,8 +517,7 @@ def runQuery(self, *args, **kwargs):
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def _runQuery(self, *args, **kwargs):
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c = self.cursor()
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d = c.execute(*args, **kwargs)
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d.addCallback(lambda c: c.fetchall())
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return d.addCallback(lambda ret: (c.close(), ret)[1])
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return d.addCallback(lambda c: c.fetchall())
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def runOperation(self, *args, **kwargs):
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"""
@@ -539,8 +538,7 @@ def runOperation(self, *args, **kwargs):
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def _runOperation(self, *args, **kwargs):
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c = self.cursor()
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d = c.execute(*args, **kwargs)
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d.addCallback(lambda _: None)
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return d.addCallback(lambda ret: (c.close(), ret)[1])
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return d.addCallback(lambda _: None)
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def runInteraction(self, interaction, *args, **kwargs):
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"""
@@ -551,7 +549,8 @@ def runInteraction(self, interaction, *args, **kwargs):
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:obj:`interaction` a new transaction will be started, so the callable
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can assume to be running all its commands in a transaction. If
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:obj:`interaction` returns a :d:`Deferred` processing will wait for it
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to fire before proceeding.
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to fire before proceeding. You should not close the provided
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:class:`~txpostgres.txpostgres.Cursor`.
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After :obj:`interaction` finishes work the transaction will be
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automatically committed. If it raises an exception or returns a
@@ -571,9 +570,6 @@ def runInteraction(self, interaction, *args, **kwargs):
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just close it, because an open transaction might have been left open in
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the database.
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Regardless of the result of :obj:`interaction`, the provided
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:class:`~txpostgres.txpostgres.Cursor` will be automatically closed.
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It is safe to call this method multiple times without waiting for the
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first query to complete.
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@@ -609,17 +605,8 @@ def justPanic(rf):
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# otherwise reraise the original failure
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return e.addCallback(lambda _: f)
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def closeCursorAndPassthrough(ret, cursor):
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try:
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cursor.close()
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except:
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log.err()
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return ret
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d.addCallback(commitAndPassthrough, c)
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d.addErrback(rollbackAndPassthrough, c)
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d.addBoth(closeCursorAndPassthrough, c)
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return d
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