From 027a287a7d93c3657eb0beb946fba52ac2964b41 Mon Sep 17 00:00:00 2001
From: Kazuhiro Sera <seratch@gmail.com>
Date: Sat, 27 May 2023 09:38:36 +0900
Subject: [PATCH] Fix #1369 ImageBlock title parsing defaults to incorrect
 behaviour when given a string (#1374)

---
 slack_sdk/models/blocks/blocks.py     | 17 ++++++++-
 tests/slack_sdk/models/test_blocks.py | 54 +++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/slack_sdk/models/blocks/blocks.py b/slack_sdk/models/blocks/blocks.py
index c38ecb0c0..22ed4f31f 100644
--- a/slack_sdk/models/blocks/blocks.py
+++ b/slack_sdk/models/blocks/blocks.py
@@ -15,6 +15,7 @@
 from .block_elements import ImageElement
 from .block_elements import InputInteractiveElement
 from .block_elements import InteractiveElement
+from ...errors import SlackObjectFormationError
 
 
 # -------------------------------------------------
@@ -216,7 +217,7 @@ def __init__(
         *,
         image_url: str,
         alt_text: str,
-        title: Optional[Union[str, dict, TextObject]] = None,
+        title: Optional[Union[str, dict, PlainTextObject]] = None,
         block_id: Optional[str] = None,
         **others: dict,
     ):
@@ -240,7 +241,19 @@ def __init__(
 
         self.image_url = image_url
         self.alt_text = alt_text
-        self.title = TextObject.parse(title)
+        parsed_title = None
+        if title is not None:
+            if isinstance(title, str):
+                parsed_title = PlainTextObject(text=title)
+            elif isinstance(title, dict):
+                if title.get("type") != PlainTextObject.type:
+                    raise SlackObjectFormationError(f"Unsupported type for title in an image block: {title.get('type')}")
+                parsed_title = PlainTextObject(text=title.get("text"), emoji=title.get("emoji"))
+            elif isinstance(title, PlainTextObject):
+                parsed_title = title
+            else:
+                raise SlackObjectFormationError(f"Unsupported type for title in an image block: {type(title)}")
+        self.title = parsed_title
 
     @JsonValidator(f"image_url attribute cannot exceed {image_url_max_length} characters")
     def _validate_image_url_length(self):
diff --git a/tests/slack_sdk/models/test_blocks.py b/tests/slack_sdk/models/test_blocks.py
index 9eb12a8a1..5461ba8d3 100644
--- a/tests/slack_sdk/models/test_blocks.py
+++ b/tests/slack_sdk/models/test_blocks.py
@@ -251,6 +251,60 @@ def test_document(self):
         }
         self.assertDictEqual(input, ImageBlock(**input).to_dict())
 
+    def test_issue_1369_title_type(self):
+        self.assertEqual(
+            "plain_text",
+            ImageBlock(
+                image_url="https://example.com/",
+                alt_text="example",
+                title="example",
+            ).title.type,
+        )
+
+        self.assertEqual(
+            "plain_text",
+            ImageBlock(
+                image_url="https://example.com/",
+                alt_text="example",
+                title={
+                    "type": "plain_text",
+                    "text": "Please enjoy this photo of a kitten",
+                },
+            ).title.type,
+        )
+
+        self.assertEqual(
+            "plain_text",
+            ImageBlock(
+                image_url="https://example.com/",
+                alt_text="example",
+                title=PlainTextObject(text="example"),
+            ).title.type,
+        )
+
+        with self.assertRaises(SlackObjectFormationError):
+            self.assertEqual(
+                "plain_text",
+                ImageBlock(
+                    image_url="https://example.com/",
+                    alt_text="example",
+                    title={
+                        "type": "mrkdwn",
+                        "text": "Please enjoy this photo of a kitten",
+                    },
+                ).title.type,
+            )
+
+            with self.assertRaises(SlackObjectFormationError):
+                self.assertEqual(
+                    "plain_text",
+                    ImageBlock(
+                        image_url="https://example.com/",
+                        alt_text="example",
+                        title=MarkdownTextObject(text="example"),
+                    ).title.type,
+                )
+
     def test_json(self):
         self.assertDictEqual(
             {