[Python] Support encode for array of string in serialization and deserialization

.chronus/changes/auto-microsoft-python-array-encode-2025-11-5-10-12-9.md

@@ -0,0 +1,8 @@
+---
+changeKind: feature
+packages:
+  - "@autorest/python"
+  - "@azure-tools/typespec-python"
+---
+
+Support encode for array of string in serialization and deserialization

packages/autorest.python/package.json

@@ -29,7 +29,7 @@
   },
   "homepage": "https://github.com/Azure/autorest.python/blob/main/README.md",
   "dependencies": {
-    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTY1OTA2NS9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.22.0.tgz",
+    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTY2MzY4Mi9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.22.0.tgz",
     "@autorest/system-requirements": "~1.0.2",
     "fs-extra": "~11.2.0",
     "tsx": "~4.19.1"

packages/typespec-python/package.json

@@ -67,7 +67,7 @@
     "js-yaml": "~4.1.0",
     "semver": "~7.6.2",
     "tsx": "~4.19.1",
-    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTY1OTA2NS9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.22.0.tgz",
+    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTY2MzY4Mi9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.22.0.tgz",
     "fs-extra": "~11.2.0"
   },
   "devDependencies": {

packages/typespec-python/test/azure/generated/authentication-api-key/authentication/apikey/_utils/model_base.py

@@ -171,6 +171,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -315,6 +330,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     return _DESERIALIZE_MAPPING.get(annotation)  # pyright: ignore
@@ -483,6 +500,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -767,6 +786,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)
 
 

packages/typespec-python/test/azure/generated/authentication-http-custom/authentication/http/custom/_utils/model_base.py

@@ -171,6 +171,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -315,6 +330,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     return _DESERIALIZE_MAPPING.get(annotation)  # pyright: ignore
@@ -483,6 +500,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -767,6 +786,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)
 
 

packages/typespec-python/test/azure/generated/authentication-oauth2/authentication/oauth2/_utils/model_base.py

@@ -171,6 +171,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -315,6 +330,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     return _DESERIALIZE_MAPPING.get(annotation)  # pyright: ignore
@@ -483,6 +500,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -767,6 +786,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)
 
 

packages/typespec-python/test/azure/generated/authentication-union/authentication/union/_utils/model_base.py

@@ -171,6 +171,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -315,6 +330,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     return _DESERIALIZE_MAPPING.get(annotation)  # pyright: ignore
@@ -483,6 +500,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -767,6 +786,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)
 
 

packages/typespec-python/test/azure/generated/azure-client-generator-core-access/specs/azure/clientgenerator/core/access/_utils/model_base.py

@@ -171,6 +171,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -315,6 +330,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     return _DESERIALIZE_MAPPING.get(annotation)  # pyright: ignore
@@ -483,6 +500,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -767,6 +786,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)
 
 

packages/typespec-python/test/azure/generated/azure-client-generator-core-alternate-type/specs/azure/clientgenerator/core/alternatetype/_utils/model_base.py

@@ -177,6 +177,21 @@ def default(self, o):  # pylint: disable=too-many-return-statements
     r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{4}\s\d{2}:\d{2}:\d{2}\sGMT"
 )
 
+_ARRAY_ENCODE_MAPPING = {
+    "pipeDelimited": "|",
+    "spaceDelimited": " ",
+    "commaDelimited": ",",
+    "newlineDelimited": "\n",
+}
+
+
+def _deserialize_array_encoded(delimit: str, attr):
+    if isinstance(attr, str):
+        if attr == "":
+            return []
+        return attr.split(delimit)
+    return attr
+
 
 def _deserialize_datetime(attr: typing.Union[str, datetime]) -> datetime:
     """Deserialize ISO-8601 formatted string into Datetime object.
@@ -321,6 +336,8 @@ def _deserialize_int_as_str(attr):
 def get_deserializer(annotation: typing.Any, rf: typing.Optional["_RestField"] = None):
     if annotation is int and rf and rf._format == "str":
         return _deserialize_int_as_str
+    if annotation is str and rf and rf._format in _ARRAY_ENCODE_MAPPING:
+        return functools.partial(_deserialize_array_encoded, _ARRAY_ENCODE_MAPPING[rf._format])
     if rf and rf._format:
         return _DESERIALIZE_MAPPING_WITHFORMAT.get(rf._format)
     if _DESERIALIZE_MAPPING.get(annotation):  # pyright: ignore
@@ -491,6 +508,8 @@ def _is_model(obj: typing.Any) -> bool:
 
 def _serialize(o, format: typing.Optional[str] = None):  # pylint: disable=too-many-return-statements
     if isinstance(o, list):
+        if format in _ARRAY_ENCODE_MAPPING and all(isinstance(x, str) for x in o):
+            return _ARRAY_ENCODE_MAPPING[format].join(o)
         return [_serialize(x, format) for x in o]
     if isinstance(o, dict):
         return {k: _serialize(v, format) for k, v in o.items()}
@@ -781,6 +800,17 @@ def _deserialize_sequence(
         return obj
     if isinstance(obj, ET.Element):
         obj = list(obj)
+    try:
+        if (
+            isinstance(obj, str)
+            and isinstance(deserializer, functools.partial)
+            and isinstance(deserializer.args[0], functools.partial)
+            and deserializer.args[0].func == _deserialize_array_encoded  # pylint: disable=comparison-with-callable
+        ):
+            # encoded string may be deserialized to sequence
+            return deserializer(obj)
+    except:  # pylint: disable=bare-except
+        pass
     return type(obj)(_deserialize(deserializer, entry, module) for entry in obj)