Reserved name populated by snake-case-field

Describe the bug

When a property name is Global, and --snake-case-field option is given, the generator creates a pydantic model named global which fails, because global is a reserved keyword.

To Reproduce

Below is a command to generator models from docker engine api. The docker engine api has a schema(Mode) that has Global as property name.

Used commandline:

$ datamodel-codegen \
    --url "https://converter.swagger.io/api/convert?url=https://docs.docker.com/engine/api/v1.30.yaml" \
    --output ex.py \
    --use-standard-collections \
    --use-generic-container-types \
    --reuse-model \
    --enable-faux-immutability \
    --strict-nullable \
    --use-schema-description \
    --snake-case-field \
    --allow-population-by-field-name \
    --target-python-version 3.7 \
    --enum-field-as-literal all

Expected behavior

I expect that code generator would select another name rather than global. such as global_.

Solution Idea

We can add an underscore if the lowercased string is reserved.

parser.base.py:camel_to_snake

@lru_cache()
def camel_to_snake(string: str) -> str:
    subbed = _UNDER_SCORE_1.sub(r'\1_\2', string)
    subbed = _UNDER_SCORE_2.sub(r'\1_\2', subbed).lower()  # +
    if keyword.iskeyword(subbed):                                                       # +
        subbed = subbed + "_"                                                                  # +
    return subbed                                                                                       # +

I’ve tested this out.

Version:

• OS: macOS 10.15.7
• Python version: 3.7.10
• datamodel-code-generator version: master branch (commit d5bc50cb9d934ae5d40e8a5dd003224bdc7527de)

[yuyupopo]

No worries 😃 Thx for the fix

[koxudaxi]

@yuyupopo I’m sorry for the late release. I pushed the new version as 0.10.0