Env vars are case sensitive (overriding only uppercase params if written in uppercase) when merge_enabled=True

[abalakh]

Let's say i have very simple yaml config with envs:

default:
  my_section:
    my_param: "default settings content"
development:
  my_section:
    my_param: "development settings content"

And i want to override my_param with env variable at some point. What's proper env var name for such case? DYNACONF_MY_SECTION__MY_PARAM works if merge_enabled=False.
However, if merge_enabled=True, DYNACONF_MY_SECTION__MY_PARAM will set my_section.MY_PARAM, not my_section.my_param.
Easy reproducer:

import os
import dynaconf


os.environ["DYNACONF_MY_SECTION__MY_PARAM"] = "env var content"

settings = dynaconf.LazySettings(
	environments=True,
	env="development",
	settings_files=["settings.yaml"],
	merge_enabled=True,
)

print(settings.my_section.my_param)
print(settings.my_section.MY_PARAM)

Running the code returns the following output:

development settings content
env var content

setting merge_enabled=False and re-running the code returns expected output:

env var content
env var content

Documentation is kinda confusing about this behavior, so i'm not 100% sure it's a bug:
On the one hand, https://www.dynaconf.com/envvars/ examples are showing uppercase env vars are correctly recognized:

export DYNACONF_PERSON__IS_ADMIN=true
assert settings.person.is_admin is True

And it works like that with merge_enabled=False
On the other - there's the following line:

Also variable access is case insensitive for the first level key

And there's https://www.dynaconf.com/configuration/#lowercase_read , so it looks like only the first level keys are designed to be case insensitive.

I'm using dynaconf 3.1.7, OS is macOS 12.2.1 if that matters.

[rochacbruno]

@abalakh this is a bug, env vars are case insensitive only on windows because on windows every env var is forced to be upper case, on linux it should have worked

[rochacbruno]

@abalakh does it work if you set

DYNACONF_MY_SECTION__my_param=othervalue

??

^that must work, however with all upper must also work if the key already exists in the settings.

[abalakh]

@rochacbruno yes, with lowercase everything works. That's what i'm currently using as workaround.

[bartolootrit]

@rochacbruno There is a similar issue. An empty lowercase YAML key value isn't overridden by an uppercase environment variable even when merge_enabled is false:

def test_empty_yaml_key_overriding(tmpdir):
    new_key_value = 'new_key_value'
    os.environ["DYNACONF_LEVEL1__KEY"] = new_key_value
    os.environ["DYNACONF_LEVEL1__KEY2"] = new_key_value
    os.environ["DYNACONF_LEVEL1__key3"] = new_key_value
    os.environ["DYNACONF_LEVEL1__KEY4"] = new_key_value

    tmpdir.join("test.yml").write(
        """
        level1:
          key: key_value
          KEY2:
          key3:
          key4:
        """
    )

    _settings = LazySettings(settings_files=['test.yml'], merge_enabled=False)

    # AssertionError: assert 'key_value' == 'new_key_value' if merge_enabled=True
    assert _settings.level1.key == new_key_value  # OK
    assert _settings.level1.key2 == new_key_value  # OK
    assert _settings.level1.key3 == new_key_value  # OK
    assert _settings.level1.key4 == new_key_value  # AssertionError: assert None == 'new_key_value'

Dynaconf is from the master branch (3.1.10.dev0)

[rochacbruno]

@bartolootrit I found the problem you described and it has to do with how dictionaries are ordered.

The env_loader is getting data as:

{'LEVEL1': {'KEY4': 'new_key_value', 'key': 'key_value', 'KEY2': None, 'key3': None, 'key4': None}}

And as dicts considers only latest added elements the None is there, I am thinking on a way to solve it.

[rochacbruno]

I think it might be fixed on this PR #795 @bartolootrit @abalakh

[bartolootrit]

@rochacbruno Yes. Thank you.