Don't depend on stringcase (closes openapi-generators#369)

ramnes · ramnes · commit 797b76fd98d3 · 2021-04-01T17:16:40.000+02:00
Let's reimplement what we need here so that we don't depend on stringcase anymore (see openapi-generators#369 for rationale). I've added a few test cases for stuff I've seen break along the way.
diff --git a/mypy.ini b/mypy.ini
@@ -8,9 +8,6 @@ strict_equality = True
 [mypy-importlib_metadata]
 ignore_missing_imports = True
 
-[mypy-stringcase]
-ignore_missing_imports = True
-
 [mypy-typer]
 ignore_missing_imports = True
 
diff --git a/openapi_python_client/utils.py b/openapi_python_client/utils.py
@@ -1,13 +1,20 @@
 import builtins
 import re
 from keyword import iskeyword
+from typing import List
 
-import stringcase
+delimiters = " _-"
 
 
 def sanitize(value: str) -> str:
-    """ Removes every character that isn't 0-9, A-Z, a-z, ' ', -, or _ """
-    return re.sub(r"[^\w _\-]+", "", value)
+    """ Removes every character that isn't 0-9, A-Z, a-z, or a known delimiter """
+    return re.sub(rf"[^\w{delimiters}]+", "", value)
+
+
+def split_words(value: str) -> List[str]:
+    """ Split a string on non-capital letters and known delimiters """
+    value = " ".join(re.split("([A-Z]?[a-z0-9]+)", value))
+    return re.findall(rf"[^{delimiters}]+", value)
 
 
 def fix_keywords(value: str) -> str:
@@ -25,22 +32,23 @@ def fix_reserved_words(value: str) -> str:
     return value
 
 
-def group_title(value: str) -> str:
-    value = re.sub(r"([A-Z]{2,})([A-Z][a-z]|[ \-_]|$)", lambda m: m.group(1).title() + m.group(2), value.strip())
-    value = re.sub(r"(^|[ _-])([A-Z])", lambda m: m.group(1) + m.group(2).lower(), value)
-    return value
-
-
 def snake_case(value: str) -> str:
-    return fix_keywords(stringcase.snakecase(group_title(sanitize(value))))
+    words = split_words(sanitize(value))
+    value = "_".join(words).lower()
+    return fix_keywords(value)
 
 
 def pascal_case(value: str) -> str:
-    return fix_keywords(stringcase.pascalcase(sanitize(value.replace(" ", ""))))
+    words = split_words(sanitize(value))
+    words = [word.capitalize() if not word.isupper() else word for word in words]
+    value = "".join(words)
+    return fix_keywords(value)
 
 
 def kebab_case(value: str) -> str:
-    return fix_keywords(stringcase.spinalcase(group_title(sanitize(value))))
+    words = split_words(sanitize(value))
+    value = "-".join(words).lower()
+    return fix_keywords(value)
 
 
 def remove_string_escapes(value: str) -> str:
diff --git a/poetry.lock b/poetry.lock
diff --git a/pyproject.toml b/pyproject.toml
@@ -21,7 +21,6 @@ include = ["CHANGELOG.md", "openapi_python_client/py.typed"]
 [tool.poetry.dependencies]
 python = "^3.6"
 jinja2 = "^2.11.1"
-stringcase = "^1.2.0"
 typer = "^0.3"
 colorama = {version = "^0.4.3", markers = "sys_platform == 'win32'"}
 shellingham = "^1.3.2"
diff --git a/tests/test_utils.py b/tests/test_utils.py
@@ -12,6 +12,7 @@ def test_snake_case_from_pascal_with_acronyms():
     assert utils.snake_case("HTTPResponse") == "http_response"
     assert utils.snake_case("APIClientHTTPResponse") == "api_client_http_response"
     assert utils.snake_case("OAuthClientHTTPResponse") == "o_auth_client_http_response"
+    assert utils.snake_case("S3Config") == "s3_config"
 
 
 def test_snake_case_from_pascal():
@@ -20,6 +21,7 @@ def test_snake_case_from_pascal():
 
 def test_snake_case_from_camel():
     assert utils.snake_case("httpResponseLowerCamel") == "http_response_lower_camel"
+    assert utils.snake_case("connectionID") == "connection_id"
 
 
 def test_kebab_case():
@@ -59,6 +61,7 @@ def test_to_valid_python_identifier():
         ("snake_case", "SnakeCase"),
         ("TLAClass", "TLAClass"),
         ("Title Case", "TitleCase"),
+        ("s3_config", "S3Config"),
     ],
 )
 def test_pascalcase(before, after):
