sqlite3 trace callback prints duplicate line

[palaviv]

BPO	26187
Nosy	@berkerpeksag, @zhangyangyu, @AnishShah, @palaviv
PRs	bpo-26187: Tests for sqlite3 trace callback #434 bpo-26187: Tests sqlite3 trace callback no duplicate on shcema changing #461

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2017-04-09.09:12:48.676>
created_at = <Date 2016-01-23.19:34:32.341>
labels = ['extension-modules', 'type-bug', '3.7']
title = 'sqlite3 trace callback prints duplicate line'
updated_at = <Date 2017-04-09.09:12:48.675>
user = 'https://github.com/palaviv'

bugs.python.org fields:

activity = <Date 2017-04-09.09:12:48.675>
actor = 'berker.peksag'
assignee = 'none'
closed = True
closed_date = <Date 2017-04-09.09:12:48.676>
closer = 'berker.peksag'
components = ['Extension Modules']
creation = <Date 2016-01-23.19:34:32.341>
creator = 'palaviv'
dependencies = []
files = []
hgrepos = []
issue_num = 26187
keywords = []
message_count = 6.0
messages = ['258874', '264549', '288876', '288913', '291359', '291361']
nosy_count = 5.0
nosy_names = ['ghaering', 'berker.peksag', 'xiang.zhang', 'anish.shah', 'palaviv']
pr_nums = ['434', '461']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue26187'
versions = ['Python 3.7']

[palaviv]

I am running the following script:

------------------------------------------

>>> import sqlite3
>>> import os
>>> import time
>>> con1 = sqlite3.connect("/tmp/test.db")
>>> con2 = sqlite3.connect("/tmp/test.db")
>>> con1.set_trace_callback(print)
>>> cur = con1.cursor()
>>> cur.execute("create table test(a)")
create table test(a)
<sqlite3.Cursor object at 0x7fb488ddf260>
>>> con2.execute("create table test2(a)")
<sqlite3.Cursor object at 0x7fb488ddf2d0>
>>> cur.execute("insert into test(a) values(1)")
BEGIN 
insert into test(a) values(1)
insert into test(a) values(1)
<sqlite3.Cursor object at 0x7fb488ddf260>
>>> for a in con1.execute("select * from test"):
...     print("result:", a)
... 
select * from test
result: (1,)

---

As you can see i get duplicate traceback print of the "insert into test(a) values(1)" line. The duplicate print has no effect on the actual db.

I have tested this both on python 3.4.3 and 3.6.0a0 on ubuntu14.04

[palaviv]

This issue will be resolved when we change the sqlite3_prepare to sqlite3_prepare_v2. So there should be a dependency on bpo-9303.

[berkerpeksag]

It would be nice to add a test case to

cpython/Lib/sqlite3/test/hooks.py

Line 204 in 86a6705

class TraceCallbackTests(unittest.TestCase):

before closing this.

[AnishShah]

I can work on this.

[berkerpeksag]

New changeset 0e6cb2e by Berker Peksag (Aviv Palivoda) in branch 'master':
bpo-26187: Test that set_trace_callback() is not called multiple times (GH-461)
0e6cb2e

[berkerpeksag]

Thanks, Anish and Aviv!