Updates various areas of the backend code that generate
JsonableErrors with translated strings to use channel
instead of stream.
Part of stream to channel rename project.
This is preparatory work towards adding a Topic model.
We plan to use the local variable name as 'topic' for
the Topic model objects.
Currently, we use *topic as the local variable name for
topic names.
We rename local variables of the form *topic to *topic_name
so that we don't need to think about type collisions in
individual code paths where we might want to talk about both
Topic objects and strings for the topic name.
Translators benefit from the extra information in the field names, and
need the reordering freedom that isn’t available with multiple
positional fields.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
These characters are not allowed and trying to create a Zulip message
with those characters throws a JsonableError in check_stream_topic.
We don't want to reject emails with those chars in the subject, so
it's best to just modify it appropriately.
Under the unicodedata distributed with Python 3.6, some Emoji are
classified as `Cn`, and not `So`:
```
$ unicode 1f929 --long
U+1F929 GRINNING FACE WITH STAR EYES
UTF-8: f0 9f a4 a9 UTF-16BE: d83edd29 Decimal: 🤩 Octal: \0374451
🤩
Category: So (Symbol, Other); East Asian width: W (wide)
Unicode block: 1F900..1F9FF; Supplemental Symbols and Pictographs
Bidi: ON (Other Neutrals)
$ python3.6 -c 'import unicodedata; print(unicodedata.category("\U0001f929"))'
Cn
$ python3.7 -c 'import unicodedata; print(unicodedata.category("\U0001f929"))'
So
```
Drop `Cn` from the list of excluded Unicode character classes, and
replace it with an explicit list of the 66 non-characters, which are
invariant.
Co-authored-by: Shlok Patel <shlokcpatel2001@gmail.com>