Add new validation to fix issue #585 (#667)

Co-authored-by: andressa.cabistani <andressa.cabistani@thoughtworks.com>

docs/validation.md

@@ -167,6 +167,23 @@ $ dynaconf validate
 This returns code 0 (success) if validation is ok.
 
 
+!!! info
+    All values in dynaconf are parsed using toml format, TOML tries to be smart
+    and infer the type of the settings variables, some variables will be automatically
+    converted to integer:
+
+    FOO = "0x..."  # hexadecimal
+    FOO = "0o..."  # Octal
+    FOO = "0b..."  # Binary
+
+All cases are on toml specs https://github.com/toml-lang/toml/blob/master/toml.abnf
+
+If you need to force a specific type casting there are 2 options.
+
+1. Use double quoted for strings ex: `FOO = "'0x...'"  will be string.
+2. Specify the type using `@`  ex: FOO = "@str 0x..."
+(available converters are `@int, @float, @bool, @json`)
+
 ## Selective Validation
 
 > **New in 3.1.6**

dynaconf/utils/parse_conf.py

@@ -316,6 +316,13 @@ def parse_conf_data(data, tomlfy=False, box_settings=None):
             )
         return _parsed
 
+    if (
+        isinstance(data, str)
+        and data.startswith(("+", "-"))
+        and data[1:].isdigit()
+    ):
+        return data
+
     # return parsed string value
     return _parse_conf_data(data, tomlfy=tomlfy, box_settings=box_settings)
 

tests/test_validators.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+from dynaconf import Dynaconf
 from dynaconf import LazySettings
 from dynaconf import ValidationError
 from dynaconf import Validator
@@ -659,3 +660,19 @@ def test_validator_descriptions_flat(tmpdir):
         "a": "a",
         "b": "a",
     }
+
+
+def test_toml_should_not_change_validator_type_with_is_type_set():
+    settings = Dynaconf(
+        validators=[Validator("TEST", is_type_of=str, default="+172800")]
+    )
+
+    assert settings.test == "+172800"
+
+
+def test_toml_should_not_change_validator_type_using_at_sign():
+    settings = Dynaconf(
+        validators=[Validator("TEST", is_type_of=str, default="@str +172800")]
+    )
+
+    assert settings.test == "+172800"