nonsensical error message for invalid input to plt.bar

[anntzer]

mpl2.0b3, py3.5.2

In [1]: plt.bar(range(3), 1)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<elided>
ValueError: incompatible sizes: argument 'height' must be length 3 or scalar

Well, it is a scalar...

[QuLogic]

Python 2 or 3?

[anntzer]

py3, but it's the same for both.

[Kojoley]

I have got the same with master and py2

>python -c "import matplotlib.pylab as plt; plt.bar(range(3), 1)"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\working\repositories\matplotlib\lib\matplotlib\pyplot.py", line 2554, in bar
    **kwargs)
  File "c:\working\repositories\matplotlib\lib\matplotlib\__init__.py", line 1916, in inner
    return func(ax, *args, **kwargs)
  File "c:\working\repositories\matplotlib\lib\matplotlib\axes\_axes.py", line 2041, in bar
    "must be length %d or scalar" % nbars)
ValueError: incompatible sizes: argument 'height' must be length 3 or scalar

[Kojoley]

The doc says that height is sequence of scalars

So exception message lies and doc lies. Function expects sequence of len(left) elements

        height = make_iterable(height)
        ...
        if orientation == 'vertical':
            ...
            nbars = len(left)
            ...
        ...
        if len(height) != nbars:
            raise ValueError("incompatible sizes: argument 'height' "
                              "must be length %d or scalar" % nbars)

>python -c "import matplotlib.pylab as plt; plt.bar(range(3), [1])"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\working\repositories\matplotlib\lib\matplotlib\pyplot.py", line 2554, in bar
    **kwargs)
  File "c:\working\repositories\matplotlib\lib\matplotlib\__init__.py", line 1916, in inner
    return func(ax, *args, **kwargs)
  File "c:\working\repositories\matplotlib\lib\matplotlib\axes\_axes.py", line 2041, in bar
    "must be length %d or scalar" % nbars)
ValueError: incompatible sizes: argument 'height' must be length 3 or scalar