Fix escaping of braces in OIDC sample config. (#9317)

This fixes the Jinja2 templates for the mapping provider.

changelog.d/9317.doc

@@ -0,0 +1 @@
+Fix the braces in the `oidc_providers` section of the sample config.

docs/sample_config.yaml

@@ -1872,9 +1872,9 @@ oidc_providers:
   #  user_mapping_provider:
   #    config:
   #      subject_claim: "id"
-  #      localpart_template: "{ user.login }"
-  #      display_name_template: "{ user.name }"
-  #      email_template: "{ user.email }"
+  #      localpart_template: "{{ user.login }}"
+  #      display_name_template: "{{ user.name }}"
+  #      email_template: "{{ user.email }}"
 
   # For use with Keycloak
   #
@@ -1901,8 +1901,8 @@ oidc_providers:
   #  user_mapping_provider:
   #    config:
   #      subject_claim: "id"
-  #      localpart_template: "{ user.login }"
-  #      display_name_template: "{ user.name }"
+  #      localpart_template: "{{ user.login }}"
+  #      display_name_template: "{{ user.name }}"
 
 
 # Enable Central Authentication Service (CAS) for registration and login.

synapse/config/oidc_config.py

@@ -198,9 +198,9 @@ def generate_config_section(self, config_dir_path, server_name, **kwargs):
           #  user_mapping_provider:
           #    config:
           #      subject_claim: "id"
-          #      localpart_template: "{{ user.login }}"
-          #      display_name_template: "{{ user.name }}"
-          #      email_template: "{{ user.email }}"
+          #      localpart_template: "{{{{ user.login }}}}"
+          #      display_name_template: "{{{{ user.name }}}}"
+          #      email_template: "{{{{ user.email }}}}"
 
           # For use with Keycloak
           #
@@ -227,8 +227,8 @@ def generate_config_section(self, config_dir_path, server_name, **kwargs):
           #  user_mapping_provider:
           #    config:
           #      subject_claim: "id"
-          #      localpart_template: "{{ user.login }}"
-          #      display_name_template: "{{ user.name }}"
+          #      localpart_template: "{{{{ user.login }}}}"
+          #      display_name_template: "{{{{ user.name }}}}"
         """.format(
             mapping_provider=DEFAULT_USER_MAPPING_PROVIDER
         )