fix: address CodeRabbit review issues on slack-full-width PR

- Capitalize 'markdown' to 'Markdown' in docs
- Replace invalid empty rich_text block with valid Slack Block Kit structure
- Add preview validation for full-width mode
- Handle markdown table truncation gracefully (row-by-row instead of mid-row)
- Align description rendering between dbt and elementary test templates
- Update tests to reflect valid rich_text block and exact assertions

Co-Authored-By: Itamar Hartstein <haritamar@gmail.com>

Author: devin-ai-integration[bot]

docs/oss/deployment-and-configuration/slack.mdx

@@ -56,12 +56,12 @@ The alert format is:
 
 ## Full-width alerts
 
-By default, Slack alerts use a narrower layout with some content in attachments. To use the full message width and show test results as a markdown table in the main message body, pass the flag when running the monitor:
+By default, Slack alerts use a narrower layout with some content in attachments. To use the full message width and show test results as a Markdown table in the main message body, pass the flag when running the monitor:
 
 ```shell
 edr monitor --slack-token <your_slack_token> --slack-channel-name <channel> --slack-full-width
 ```
 
-With `--slack-full-width`, alerts are sent using Slack Block Kit in the main message body instead of attachments, so the full channel width is used and test result samples appear as formatted markdown tables.
+With `--slack-full-width`, alerts are sent using Slack Block Kit in the main message body instead of attachments, so the full channel width is used and test result samples appear as formatted Markdown tables.
 
 ---

docs/oss/guides/alerts/send-slack-alerts.mdx

@@ -24,7 +24,7 @@ Make sure to run the following command after your dbt runs and tests:
 edr monitor --slack-token <your_slack_token> --slack-channel-name <slack_channel_to_post_at> --group-by [table | alert]
 ```
 
-Add `--slack-full-width` to use the full message width and show test results as markdown tables. See [Slack setup - Full-width alerts](/oss/deployment-and-configuration/slack#full-width-alerts).
+Add `--slack-full-width` to use the full message width and show test results as Markdown tables. See [Slack setup - Full-width alerts](/oss/deployment-and-configuration/slack#full-width-alerts).
 
 Or just `edr monitor` if you used `config.yml`. Please note that when you specify the --slack-channel-name, it's the
 default channel name to which all the alerts will be sent that are not attributed to any custom channel. Therefore,

elementary/monitor/data_monitoring/alerts/integrations/slack/message_builder.py

@@ -35,9 +35,22 @@ def get_slack_message(
         alert_schema: SlackAlertMessageSchema,
     ) -> SlackMessageSchema:
         if self.full_width:
-            # Empty rich_text block forces Slack to use full message width for following
-            # blocks instead of the narrower attachment-style layout.
-            self._add_always_displayed_blocks([{"type": "rich_text", "elements": []}])
+            # A rich_text block at the start forces Slack to use full message width
+            # for following blocks instead of the narrower attachment-style layout.
+            # The elements array must be non-empty per Slack Block Kit API.
+            self._add_always_displayed_blocks(
+                [
+                    {
+                        "type": "rich_text",
+                        "elements": [
+                            {
+                                "type": "rich_text_section",
+                                "elements": [{"type": "text", "text": " "}],
+                            }
+                        ],
+                    }
+                ]
+            )
         self.add_title_to_slack_alert(alert_schema.title)
         self.add_preview_to_slack_alert(alert_schema.preview)
         self.add_details_to_slack_alert(alert_schema.details)
@@ -55,10 +68,10 @@ def add_preview_to_slack_alert(
     ):
         if not preview_blocks:
             return
+        validated_preview_blocks = self._validate_preview_blocks(preview_blocks)
         if self.full_width:
-            self._add_always_displayed_blocks(preview_blocks)
+            self._add_always_displayed_blocks(validated_preview_blocks)
         else:
-            validated_preview_blocks = self._validate_preview_blocks(preview_blocks)
             self._add_blocks_as_attachments(validated_preview_blocks)
 
     def add_details_to_slack_alert(

elementary/monitor/data_monitoring/alerts/integrations/slack/slack.py

@@ -222,8 +222,10 @@ def _get_dbt_test_template(
             TEST_RESULTS_SAMPLE_FIELD in (alert.alert_fields or DEFAULT_ALERT_FIELDS)
             and alert.test_rows_sample
         ):
+            # Reserve space for the code fence (``` prefix and ``` suffix = 6 chars)
+            table_max_length = SectionBlock.text_max_length - 6
             test_rows_sample_table = list_of_dicts_to_markdown_table(
-                alert.test_rows_sample
+                alert.test_rows_sample, max_length=table_max_length
             )
             result.extend(
                 [
@@ -361,21 +363,12 @@ def _get_elementary_test_template(
             )
 
         if DESCRIPTION_FIELD in (alert.alert_fields or DEFAULT_ALERT_FIELDS):
-            if alert.test_description:
-                preview.extend(
-                    [
-                        self.message_builder.create_text_section_block("*Description*"),
-                        self.message_builder.create_context_block(
-                            [alert.test_description]
-                        ),
-                    ]
-                )
-            else:
-                preview.append(
-                    self.message_builder.create_text_section_block(
-                        "*Description*\n_No description_"
-                    )
+            description_text = alert.test_description or "_No description_"
+            preview.append(
+                self.message_builder.create_text_section_block(
+                    f"*Description*\n{description_text}"
                 )
+            )
 
         result = []
         if (
@@ -384,7 +377,7 @@ def _get_elementary_test_template(
         ):
             result.extend(
                 [
-                    self.message_builder.create_context_block(["*Result message*"]),
+                    self.message_builder.create_text_section_block("*Result message*"),
                     self.message_builder.create_text_section_block(
                         f"```{alert.error_message.strip()}```"
                     ),

elementary/utils/json_utils.py

@@ -112,12 +112,17 @@ def _format_value(value: Any) -> str:
     return str(value)
 
 
-def list_of_dicts_to_markdown_table(data: List[Dict[str, Any]]) -> str:
+def list_of_dicts_to_markdown_table(
+    data: List[Dict[str, Any]], max_length: Optional[int] = None
+) -> str:
     """
     Convert a list of dictionaries with consistent keys to a markdown table string.
 
     Args:
         data: List of dictionaries
+        max_length: Optional maximum character length for the output. If the full
+            table exceeds this limit, rows are removed from the end and a
+            "(truncated)" note is appended to avoid cutting mid-row.
 
     Returns:
         A markdown-formatted table string using GitHub table format
@@ -126,6 +131,31 @@ def list_of_dicts_to_markdown_table(data: List[Dict[str, Any]]) -> str:
         return ""
 
     processed_data = [{k: _format_value(v) for k, v in row.items()} for row in data]
-    return tabulate(
+    full_table = tabulate(
         processed_data, headers="keys", tablefmt="github", disable_numparse=True
     )
+
+    if max_length is None or len(full_table) <= max_length:
+        return full_table
+
+    # Truncate by removing rows from the end until the table fits
+    truncation_note = "\n(truncated)"
+    effective_max = max_length - len(truncation_note)
+    for row_count in range(len(processed_data) - 1, 0, -1):
+        table = tabulate(
+            processed_data[:row_count],
+            headers="keys",
+            tablefmt="github",
+            disable_numparse=True,
+        )
+        if len(table) <= effective_max:
+            return table + truncation_note
+
+    # Even a single row doesn't fit — return what we can with a note
+    single_row_table = tabulate(
+        processed_data[:1],
+        headers="keys",
+        tablefmt="github",
+        disable_numparse=True,
+    )
+    return single_row_table + truncation_note

tests/unit/monitor/data_monitoring/alerts/integrations/slack/test_slack_alert_message_builder.py

@@ -177,11 +177,12 @@ def test_add_details_to_slack_alert():
 
 
 def test_full_width_preview_goes_to_blocks_not_attachments():
-    """With full_width=True, preview blocks are added to main blocks."""
+    """With full_width=True, preview blocks are validated and added to main blocks."""
     message_builder = SlackAlertMessageBuilder(full_width=True)
     block = message_builder.create_header_block("Preview header")
     message_builder.add_preview_to_slack_alert([block])
-    assert len(message_builder.slack_message["blocks"]) == 1
+    # Preview blocks are validated (padded to _MAX_ALERT_PREVIEW_BLOCKS)
+    assert len(message_builder.slack_message["blocks"]) == 5
     assert message_builder.slack_message["blocks"][0] == block
     assert message_builder.slack_message["attachments"][0]["blocks"] == []
 
@@ -210,11 +211,23 @@ def test_full_width_get_slack_message_structure():
     result = message_builder.get_slack_message(alert_schema=schema)
 
     blocks = result.blocks
-    assert len(blocks) >= 5
-    assert blocks[0] == {"type": "rich_text", "elements": []}
+    valid_rich_text_block = {
+        "type": "rich_text",
+        "elements": [
+            {
+                "type": "rich_text_section",
+                "elements": [{"type": "text", "text": " "}],
+            }
+        ],
+    }
+    assert blocks[0] == valid_rich_text_block
     assert blocks[1] == title
     assert blocks[2]["type"] == "divider"
+    # Preview blocks are validated and padded to _MAX_ALERT_PREVIEW_BLOCKS (5)
     assert blocks[3] == preview_block
-    assert blocks[4] == detail_block
+    # Blocks 4-7 are padding from preview validation
+    # Then detail_block follows
+    assert blocks[8] == detail_block
+    assert len(blocks) == 9
 
     assert result.attachments == []