Revert "fix(auth): parse hostname for mTLS and PSC endpoint certifica…

[attharva-24]

(#18153)

This reverts commit b642373.

[macastelaz]

Just for additional context - we wanted to await additional approvals before merging the PR being reverted here

[gemini-code-assist]

Code Review

This pull request removes the is_mtls_endpoint helper function and replaces it with inline substring checks for mTLS URL prefixes in both the requests and urllib3 transport modules. The review feedback highlights a potential TypeError if the url parameter is a bytes or urllib3.util.Url object rather than a string, recommending robust type-checking and decoding. Additionally, it is advised to avoid list comprehensions inside any() in the urllib3 transport to preserve short-circuiting behavior.

[gemini-code-assist]

Using a simple substring check (prefix in url) on the raw url parameter can raise a TypeError if url is a bytes object or a urllib3.util.Url object. To ensure robust type handling, check for a .url attribute, safely decode bytes to UTF-8, and fall back to string conversion.

                MTLS_URL_PREFIXES = [
                    "mtls.googleapis.com",
                    "mtls.sandbox.googleapis.com",
                ]
                url_str = url.url if hasattr(url, "url") else (url.decode("utf-8") if isinstance(url, bytes) else str(url))
                use_mtls = self.is_mtls and any(
                    prefix in url_str for prefix in MTLS_URL_PREFIXES
                )

References

1. When parsing or validating URLs that may be passed as urllib3.util.Url objects, bytes, or strings, ensure robust type handling by checking for a .url attribute, safely decoding bytes to UTF-8, and falling back to string conversion to prevent TypeErrors during parsing.

[gemini-code-assist]

Using a list comprehension inside any() defeats short-circuiting. Additionally, url can be a urllib3.util.Url object, bytes, or str. To prevent TypeError, check for a .url attribute, safely decode bytes to UTF-8, and fall back to string conversion.

Suggested change

	use_mtls = False
	if self._is_mtls:
	MTLS_URL_PREFIXES = ["mtls.googleapis.com", "mtls.sandbox.googleapis.com"]
	use_mtls = any([prefix in url for prefix in MTLS_URL_PREFIXES])
	use_mtls = False
	if self._is_mtls:
	MTLS_URL_PREFIXES = ["mtls.googleapis.com", "mtls.sandbox.googleapis.com"]
	url_str = url.url if hasattr(url, "url") else (url.decode("utf-8") if isinstance(url, bytes) else str(url))
	use_mtls = any(prefix in url_str for prefix in MTLS_URL_PREFIXES)

References

1. When parsing or validating URLs that may be passed as urllib3.util.Url objects, bytes, or strings, ensure robust type handling by checking for a .url attribute, safely decoding bytes to UTF-8, and falling back to string conversion to prevent TypeErrors during parsing.