SIM401 should not apply to non-concrete default values

[thomasdesr]

Thanks again for Ruff ❤️

As of ruff==0.0.219 SIM401 seems to be incorrectly applied when the default value is not a constant value.

import asyncio


async def some_async_func():
    await asyncio.sleep(10)


async def foo():
    d = {"key": "value"}
    key = "key"

    if key in d:
        value = d[key]
    else:
        value = await some_async_func()

    return value

Believes it can be simplified (& maybe more dangerously will be auto-fixed) to:

import asyncio


async def some_async_func():
    await asyncio.sleep(10)


async def foo():
    d = {"key": "value"}
    key = "key"

    value = d.get(key, await some_async_func())

    return value

However these two are not interchangeable as some_async_func() may be arbitrarily expensive as demonstrated here by the asyncio.sleep(10)

Note: This is also a bug in upstream flake8-simplify MartinThoma/flake8-simplify#166

[charliermarsh]

Ahh, good catch! We can fix this.

[thomasdesr]

Thanks!

[charliermarsh]

I went off some heuristics (ignore any expressions containing function calls, awaits, etc.) — let me know if it misses anything going forward.

[thomasdesr]

They look like sufficient for my code base! Thanks so much :D

[andersk]

We should also ignore subscripting, since it might throw KeyError. For example, this fix is wrong:

-             if "title" in fileinfo: 
-                 file_name = fileinfo["title"] 
-             else: 
-                 file_name = fileinfo["name"] 
+             file_name = fileinfo.get("title", fileinfo["name"])

[charliermarsh]

Makes sense, I can fix that.