How can I comment in a Jinja directive? - jinja2

Question

I have a Jinja set directive as follows:
{% set mylist = [
"item 1",
"another item",
"yet another item",
] %}
I would like to add a comment to the second list item. Does Jinja support that? I've tried the following:
{% set mylist = [
"item 1",
"another item", # My comment
"yet another item",
] %}
and
{% set mylist = [
"item 1",
"another item", ## My comment
"yet another item",
] %}
, but none of them work. I'm using Jinja 2.6.

Answer 1

Since you are using Jinja 2.2+ then you can use whatever your environment configures for line_comment_prefix (part of the line statements feature). This feature must be enabled by the application that Jinja is embedded in (for example, in Flask, this is done by setting app.jinja_options['line_comment_prefix'] = "whatever#you$want").
app = Flask(__name__)
app.jinja_options['line_statement_prefix'] = '#'
app.jinja_options['line_comment_prefix'] = '#::'
Then you can write a template that uses line comments:
{% set mylist = [
"first item",
"another item", #:: needed for raisins - see #12345
"a third item"
] %}
If you are using Jinja 2.1 or lower then those versions do not support inline comments. However, you can use a comment block:
{#
BUG: Added "another item" because of raisins.
Don't remove it until #12345 is fixed
#}
{% set mylist = [
"item 1",
"another item",
"yet another item",
] %}

Answer 2

I guess everyone's going to find that out via documentation but just in case, I'll leave it here as well:
Since Jinja 2.2, line-based comments are available as well. For
example, if the line-comment prefix is configured to be ##, everything
from ## to the end of the line is ignored (excluding the newline
sign):
# for item in seq:
<li>{{ item }}</li> ## this comment is ignored
# endfor