[pypy-issue] Issue #2872: Default isolation mode is different on pypy? (pypy/pypy)

[Ned Batchelder]

New issue 2872: Default isolation mode is different on pypy?
https://bitbucket.org/pypy/pypy/issues/2872/default-isolation-mode-is-different-on

Ned Batchelder:

multisql.py:
```
import sqlite3
import sys

print(sys.version)
print(sqlite3.sqlite_version)

con = sqlite3.connect("the.db")
with con:
    con.execute("pragma journal_mode=off")
    con.execute("create table foo (bar text)")
    con.execute("insert into foo (bar) values (?)", ("hello",))
    con.execute("insert into foo (bar) values (?)", ("goodbye",))

con = sqlite3.connect("the.db")
with con:
    print(list(con.execute("select * from foo")))
```
Running it on CPython 3.6:
```
$ .tox/py36/bin/python /tmp/multisql.py
3.6.6 (default, Jun 28 2018, 07:43:54)
[GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)]
3.19.3
[('hello',), ('goodbye',)]
```
Running it on PyPy 6.0.0:
```
$ .tox/pypy/bin/python /tmp/multisql.py
2.7.13 (ab0b9caf307d, Apr 24 2018, 18:05:02)
[PyPy 6.0.0 with GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.1)]
3.19.3
Traceback (most recent call last):
  File "/tmp/multisql.py", line 12, in <module>
    con.execute("insert into foo (bar) values (?)", ("goodbye",))
  File "/usr/local/pythonz/pythons/PyPy-v6.0.0/lib_pypy/_sqlite3.py", line 487, in __exit__
    self.commit()
  File "/usr/local/pythonz/pythons/PyPy-v6.0.0/lib_pypy/_sqlite3.py", line 456, in commit
    raise self._get_exception(ret)
OperationalError: cannot commit transaction - SQL statements in progress
```

I can't find a difference detectable from the sqlite3 module that would explain the difference.