test_history failure

I am trying to package ipython 7.0.1 for openSUSE and I am getting the following error in the unit tests:

======================================================================
FAIL: IPython.core.tests.test_history.test_history
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/usr/lib/python3.6/site-packages/IPython/core/tests/test_history.py", line 113, in test_history
    newhist[3]])
AssertionError: Lists differ: [(1, [51 chars]rn test'), (1, 3, "b='€Æ¾÷ß'"), (2, 1, 'z=5'), (2, 3, "k='p'")] != [(1, [51 chars]rn test'), (1, 3, "b='€Æ¾÷ß'"), (2, 3, "k='p'"), (2, 4, 'z=5')]

First differing element 3:
(2, 1, 'z=5')
(2, 3, "k='p'")

  [(1, 1, 'a=1'),
   (1, 2, 'def f():\n    test = 1\n    return test'),
   (1, 3, "b='€Æ¾÷ß'"),
-  (2, 1, 'z=5'),
-  (2, 3, "k='p'")]
?                 ^

+  (2, 3, "k='p'"),
?                 ^

+  (2, 4, 'z=5')]
-------------------- >> begin captured stdout << ---------------------
def f():
    test = 1
    return test
b='€Æ¾÷ß'
The following commands were written to file `/tmp/tmphhgt1b7l/tmpsytny8bh/test4.py`:
a=1
def f():
    test = 1
    return test
b='€Æ¾÷ß'

--------------------- >> end captured stdout << ----------------------
    """Fail immediately, with the given message."""
>>  raise self.failureException('Lists differ: [(1, [51 chars]rn test\'), (1, 3, "b=\'€Æ¾÷ß\'"), (2, 1, \'z=5\'), (2, 3, "k=\'p\'")] != [(1, [51 chars]rn test\'), (1, 3, "b=\'€Æ¾÷ß\'"), (2, 3, "k=\'p\'"), (2, 4, \'z=5\')]\n\nFirst differing element 3:\n(2, 1, \'z=5\')\n(2, 3, "k=\'p\'")\n\n  [(1, 1, \'a=1\'),\n   (1, 2, \'def f():\\n    test = 1\\n    return test\'),\n   (1, 3, "b=\'€Æ¾÷ß\'"),\n-  (2, 1, \'z=5\'),\n-  (2, 3, "k=\'p\'")]\n?                 ^\n\n+  (2, 3, "k=\'p\'"),\n?                 ^\n\n+  (2, 4, \'z=5\')]')
    

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

It looks like the last two list elements have switched places but I don’t know why that might be the case.

---

EDIT:

We can likely fix this issue in two steps:

1. mark the test as skip (or known fail) for the range of sqlite versions that appear to be affected.
2. actually figure out if this is a change in behavior worth fixing or if the test should be updated accordingly.

[Carreau]

I think it’s without underscore on IPython codebase.

For example there.

@dsblank have you tried RipGrep ? Really good: skip .git by default, search recursively by default, color highlight, and filter by file types. Fr example search for skipif only in python files:

$ rg @skipif -tpy
IPython/extensions/tests/test_autoreload.py
133:    @skipif(sys.version_info < (3, 6))

IPython/core/tests/test_interactiveshell.py
531:    @skipif(not hasattr(signal, 'SIGALRM'))

IPython/lib/tests/test_latextools.py
47:@skipif_not_matplotlib
62:@skipif_not_matplotlib

IPython/lib/tests/test_display.py
182:@skipif_not_numpy
 ~/dev/ipython[master ✗] $ rg @skip_if -tpy
IPython/lib/tests/test_clipboard.py
7:@skip_if_no_x11

IPython/utils/tests/test_path.py
102:@skip_if_not_win32
117:@skip_if_not_win32
157:@skip_if_not_win32
377:    @skip_if_not_win32
468:    @skip_if_not_win32

… and 10x faster on my machine.

[jcbollinger]

For future reference and maybe a real fix sometime, this appears to be happening because ipython uses an SQL “GROUP BY” clause to squash duplicates, while also selecting and ordering by columns that are neither grouping columns nor aggregate functions (session and line). Neither SQL nor sqlite specify from which row of each resulting group the values for those so-called “bare” columns will be drawn, and apparently sqlite’s actual behavior changed in that regard.

I tried a couple of variations on the generated SQL, with no success against sqlite3 3.26.0. There are certainly ways to do it, but there’s a question of the size of the changes required and their effect on search performance.