2.9 template optimizer seems to apply filters too early.

[mjpieters]

A {{ [1, 2, 3] | random }} interpolation results in one value being picked and re-used, no matter how often that interpolation is run inside a loop:

$ cat test.py
from jinja2 import Template
template = Template('''
{%- for i in range(10) -%}
{{ ['foo', 'bar', 'baz', 'eggs', 'ham', 'spam'] | random }}{{ ' ' }}
{%- endfor %}
''')
print(template.render())
$ python3 test.py
baz baz baz baz baz baz baz baz baz baz

This started with 2.9 and is present in 2.9.6 still. 2.8.1 doesn't show this behaviour (downgrading with pip install -U Jinja2==2.8.1 results in a proper random series of choices).

When you make the list a variable, things work as expected as well, so {% set seq = [...] %} then {{ seq | random }} works fine, as well as passing in the sequence as a template variable on rendering.

[davidism]

Fixed by #734 by making random a context filter. If I have time I'll go back and figure out what changed between 2.8 and 2.9.