fix: preserve whitespace in ContentText for streaming

Move the [empty string] conversion from __init__ to __str__ in ContentText
so that whitespace-only text is preserved internally while still displaying
nicely. This fixes streaming tests where newlines between words were being
converted to [empty string].

Also revert the .isspace() filtering in stream_content() methods since
ContentText now preserves the original text.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: cpsievert

chatlas/_content.py

@@ -168,13 +168,9 @@ class ContentText(Content):
     text: str
     content_type: ContentTypeEnum = "text"
 
-    def __init__(self, **data: Any):
-        super().__init__(**data)
-
-        if self.text == "" or self.text.isspace():
-            self.text = "[empty string]"
-
     def __str__(self):
+        if self.text == "" or self.text.isspace():
+            return "[empty string]"
         return self.text
 
 

chatlas/_provider_anthropic.py

@@ -467,12 +467,12 @@ def stream_content(self, chunk):
         if chunk.type == "content_block_delta":
             if chunk.delta.type == "text_delta":
                 text = chunk.delta.text
-                if not text:
+                if text is None:
                     return None
                 return ContentText(text=text)
             if chunk.delta.type == "thinking_delta":
                 thinking = chunk.delta.thinking
-                if not thinking:
+                if thinking is None:
                     return None
                 return ContentThinking(thinking=thinking)
         return None

chatlas/_provider_google.py

@@ -375,7 +375,7 @@ def stream_content(self, chunk):
                 return None
             part = parts[0]
             text = part.text
-            if not text:
+            if text is None:
                 return None
             # Check if this is thinking content
             if getattr(part, "thought", False):

chatlas/_provider_openai.py

@@ -295,12 +295,12 @@ def _chat_perform_args(
     def stream_content(self, chunk):
         if chunk.type == "response.output_text.delta":
             # https://platform.openai.com/docs/api-reference/responses-streaming/response/output_text/delta
-            if not chunk.delta:
+            if chunk.delta is None:
                 return None
             return ContentText(text=chunk.delta)
         if chunk.type == "response.reasoning_summary_text.delta":
             # https://platform.openai.com/docs/api-reference/responses-streaming/response/reasoning_summary_text/delta
-            if not chunk.delta:
+            if chunk.delta is None:
                 return None
             return ContentThinking(thinking=chunk.delta)
         if chunk.type == "response.reasoning_summary_text.done":

chatlas/_provider_openai_completions.py

@@ -196,7 +196,7 @@ def stream_content(self, chunk):
         if not chunk.choices:
             return None
         text = chunk.choices[0].delta.content
-        if not text:
+        if text is None:
             return None
         return ContentText(text=text)
 

chatlas/_provider_snowflake.py

@@ -363,7 +363,7 @@ def stream_content(self, chunk):
         if delta is None or "content" not in delta:
             return None
         text = delta["content"]
-        if not text:
+        if text is None:
             return None
         return ContentText(text=text)