missing matplotlib agg backend for builder

[Timmie]

The following recipe fails:
https://code.launchpad.net/~pythonxy/+archive/individual-devel/+build/3116522

with
[...]
test_upsample_generic (pandas.tests.test_functions.TestReductions) ... ok
test_upsample_max (pandas.tests.test_functions.TestReductions) ... ok
test_upsample_mean (pandas.tests.test_functions.TestReductions) ... ok
test_upsample_min (pandas.tests.test_functions.TestReductions) ... ok
test_boxplot (pandas.tests.test_graphics.TestDataFramePlots) ... ERROR
test_hist (pandas.tests.test_graphics.TestDataFramePlots) ... ERROR
test_plot (pandas.tests.test_graphics.TestDataFramePlots) ... ERROR
test_plot_bar (pandas.tests.test_graphics.TestDataFramePlots) ... ERROR
test_plot_int_columns (pandas.tests.test_graphics.TestDataFramePlots) ... ERROR
test_hist (pandas.tests.test_graphics.TestSeriesPlots) ... ERROR
test_plot (pandas.tests.test_graphics.TestSeriesPlots) ... ERROR
test_agg_apply_corner (pandas.tests.test_groupby.TestGroupBy) ... ok
test_agg_must_agg (pandas.tests.test_groupby.TestGroupBy) ... ok
test_agg_python_multiindex (pandas.tests.test_groupby.TestGroupBy) ... ok

[...]

ERROR: test_boxplot (pandas.tests.test_graphics.TestDataFramePlots)
----------------------------------------------------------------------
Traceback (most recent call last):

[...]

see the log:
https://launchpadlibrarian.net/90900640/buildlog.txt.gz

according to Pandas develpers, the matplotlib installation of the builder is missing the AGG backend:
https://github.com/wesm/pandas/issues/674

Could this be installed?

[Martin Pool (mbp)]

If you need this library, you need to declare it as a dependency of
your source package. By design, Launchpad does not add random
dependencies into the chroot for all packages.

[Timmie (timmie)]

It is a build-dependency:
http://bazaar.launchpad.net/~pythonxy/pythonxy/pandas_debian/view/head:/control#L16

Build-Depends: debhelper (>= 7),
               python-all-dev (>= 2.5), python-support (>= 0.6),
               python-setuptools, cython (>= 0.12~),
               python-numpy, python-dateutil,
               python-scipy,
               python-scikits.statsmodels,
               python-tz,
               python-tables, python-xlrd,
               python-sphinx (>= 1.0~),
               python-nose,
               python-matplotlib,

Is this wrongly done?

[Martin Pool (mbp)]

Can you see if you can build it locally, in a clean environment
(probably using pbuilder/sbuilder)?

[Robert Collins (lifeless)]

The builders install what package dependencies tell them to install: the issue you are having is user data, not a code bug.

[Martin Pool (mbp)]

Upstream says this error means you're missing tkinter, so I guess you need python-tk.