Read the CLI option environment variables the way they are documented

Two defects in the same block, both of which make a documented option unusable or inverted: * the boolean options went through bool(), so CHECK_DELIVERABILITY=false, TEST_ENVIRONMENT=0 and any other non-empty value all meant *true* - the check the user asked to turn off is the one that runs, including the DNS lookups; * DEFAULT_TIMEOUT was forwarded as a keyword argument, but validate_email has no such parameter (the real ones are timeout and the module-level DEFAULT_TIMEOUT), so setting it always ended in TypeError: validate_email() got an unexpected keyword argument 'default_timeout'. The module documents that "keyword arguments to validate_email can be set in environment variables of the same name but uppercase" and 2.0.0 added the option reading, so both spellings should mean what the docs say. The falsy set is a superset of what bool() rejected before (the empty string, plus 0/false/no/off, case- and space-insensitive), so nothing that worked changes.
feiiiiii5 · Sep 28, 2026 · Sep 28, 2026 · 27c16b57b15b1c77d47ed248f6c49ce691a07340
commit 27c16b57b15b1c77d47ed248f6c49ce691a07340
diff --git a/email_validator/__main__.py b/email_validator/__main__.py
@@ -33,10 +33,15 @@ def main(dns_resolver: Optional[_Resolver] = None) -> None:
                     'ALLOW_DISPLAY_NAME',
                     'GLOBALLY_DELIVERABLE', 'CHECK_DELIVERABILITY', 'TEST_ENVIRONMENT'):
         if varname in os.environ:
-            options[varname.lower()] = bool(os.environ[varname])
+            # bool() would make any non-empty string True, so e.g.
+            # CHECK_DELIVERABILITY=false would enable the check.
+            options[varname.lower()] = os.environ[varname].strip().lower() not in ('', '0', 'false', 'no', 'off')
     for varname in ('DEFAULT_TIMEOUT',):
         if varname in os.environ:
-            options[varname.lower()] = float(os.environ[varname])
+            # DEFAULT_TIMEOUT is a module-level default read by
+            # caching_resolver(), not a keyword argument of validate_email.
+            import email_validator
+            email_validator.DEFAULT_TIMEOUT = int(os.environ[varname])
 
     if len(sys.argv) == 1:
         # Validate the email addresses passed line-by-line on STDIN.

diff --git a/tests/test_main.py b/tests/test_main.py
@@ -81,6 +81,43 @@ def test_main_multi_input(monkeypatch: pytest.MonkeyPatch, capsys: pytest.Captur
     assert test_cases[3] in stdout
 
 
+@pytest.mark.parametrize('value', ['false', 'False', 'FALSE', '0', 'no', 'off', ' '])
+def test_main_falsy_boolean_option_from_env(monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str], value: str) -> None:
+    # Options are set from environment variables of the same name in upper
+    # case. A falsy value there must turn the option off, not on.
+    import json
+    test_email = 'test@xkxufoekjvjfjeodlfmdfjcu.com'  # this domain does not exist in DNS
+    monkeypatch.setenv('CHECK_DELIVERABILITY', value)
+    monkeypatch.setattr('sys.argv', ['email_validator', test_email])
+    validator_command_line_tool(dns_resolver=RESOLVER)
+    stdout, _ = capsys.readouterr()
+    assert json.loads(str(stdout))["normalized"] == test_email
+
+
+@pytest.mark.parametrize('value', ['false', 'False', '0', 'no', 'off', ' '])
+def test_main_falsy_test_environment_from_env(monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str], value: str) -> None:
+    # test_environment off means the reserved "test" domain names are rejected.
+    monkeypatch.setenv('TEST_ENVIRONMENT', value)
+    monkeypatch.setattr('sys.argv', ['email_validator', 'me@foo.test'])
+    validator_command_line_tool(dns_resolver=RESOLVER)
+    stdout, _ = capsys.readouterr()
+    assert stdout == 'The part after the @-sign is a special-use or reserved name that cannot be used with email.\n'
+
+
+def test_main_default_timeout_from_env(monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str]) -> None:
+    import json
+    import email_validator
+    test_email = 'google@google.com'
+    # Set up the restore of the module-level default, which main() overwrites.
+    monkeypatch.setattr('email_validator.DEFAULT_TIMEOUT', email_validator.DEFAULT_TIMEOUT)
+    monkeypatch.setenv('DEFAULT_TIMEOUT', '5')
+    monkeypatch.setattr('sys.argv', ['email_validator', test_email])
+    validator_command_line_tool(dns_resolver=RESOLVER)
+    stdout, _ = capsys.readouterr()
+    assert json.loads(str(stdout))["normalized"] == test_email
+    assert email_validator.DEFAULT_TIMEOUT == 5
+
+
 def test_bytes_input() -> None:
     input_email = b"testaddr@example.tld"
     valid_email = validate_email(input_email, check_deliverability=False)