pip installer: fix typing issues for http repos

src/poetry/installation/pip_installer.py

@@ -12,6 +12,7 @@
 from poetry.core.pyproject.toml import PyProjectTOML
 
 from poetry.installation.base_installer import BaseInstaller
+from poetry.repositories.http import HTTPRepository
 from poetry.utils._compat import encode
 from poetry.utils.helpers import safe_rmtree
 from poetry.utils.pip import pip_install
@@ -57,23 +58,28 @@ def install(self, package: Package, update: bool = False) -> None:
                 )
                 args += ["--trusted-host", parsed.hostname]
 
-            if repository.cert:
-                args += ["--cert", str(repository.cert)]
+            if isinstance(repository, HTTPRepository):
+                if repository.cert:
+                    args += ["--cert", str(repository.cert)]
 
-            if repository.client_cert:
-                args += ["--client-cert", str(repository.client_cert)]
+                if repository.client_cert:
+                    args += ["--client-cert", str(repository.client_cert)]
 
-            index_url = repository.authenticated_url
+                index_url = repository.authenticated_url
+
+                args += ["--index-url", index_url]
 
-            args += ["--index-url", index_url]
             if (
                 self._pool.has_default()
                 and repository.name != self._pool.repositories[0].name
             ):
-                args += [
-                    "--extra-index-url",
-                    self._pool.repositories[0].authenticated_url,
-                ]
+                first_repository = self._pool.repositories[0]
+
+                if isinstance(first_repository, HTTPRepository):
+                    args += [
+                        "--extra-index-url",
+                        first_repository.authenticated_url,
+                    ]
 
         if update:
             args.append("-U")