config: Missing correspondence silently fails? sections = ["{WROTE_AB}", ...] and known_{meant_abc}

[EricCousineau-TRI]

Would it be possible to have isort complain if sections is defined without a corresponding known_{snake_case} definition? -- or conversely, if known_{snake_case} is defined, but is not used in sections?

I just spent some time chasing down an issue where section correspondence didn't exist, but it silently failed.

In my specific cast, I had the following TOML config portion:

[tool.isort]
# ...
# [ Sections ]
# See: https://github.com/timothycrosley/isort#custom-sections-and-ordering
# This determines the ordering of imports.
sections = [
    # {builtin}
    "FUTURE",
    # {builtin} + extra_standard_library
    "STDLIB",
    # known_third_party
    "THIRDPARTY",
    # known_robotlocomotion_upstream
    "ROBOTLOOMOTION_UPSTREAM",
    # known_first_party
    "FIRSTPARTY",
    # {builtin}
    "LOCALFOLDER",
]
# TODO(eric.cousineau): Rename to LCM ecosystem?
known_robotlocomotion_upstream = [
    "bot_core",
]
default_section = "THIRDPARTY"

But isort==5.1.3 was formatting the following file:

import time

import numpy as np

import bot_core

into this:

import time

import bot_core
import numpy as np

which was not what I wanted.

In the end, it was because I misspelled "ROBOTLOOMOTION_UPSTREAM" - it was missing the C 🤦

[timothycrosley]

Thanks for reporting this! I think the suggested approach is solid and I'll be aiming to get the improved error handling / warning in the 5.2.0 release.

Thanks!

~Timothy