Unclear support for `markdown_text` option.

[brendo]

I was attempting to send markdown_text ref to the chat_postMessage but am encountering some issues.

The reference docs indicate that when passing markdown_text, text should be omitted:

Accepts message text formatted in markdown. This argument should not be used in conjunction with blocks or text. Limit this field to 12,000 characters.

If I do so, eg. .chat_postMessage({ markdown_text: "*Hello*"}), an ArgumentError is raised as I haven't passed text.

slack-ruby-client/lib/slack/web/api/endpoints/chat.rb

Line 196 in adfde85

raise ArgumentError, 'At least one of :attachments, :blocks, :text is required' if options[:attachments].nil? && options[:blocks].nil? && options[:text].nil?

If I pass text and markdown_text, eg. .chat_postMessage({ markdown_text: "*Hello*", text: "*Hello*", mrkdwn: false}), the request goes through to the API but then fails with a Slack::Web::Api::Errors::MarkdownTextConflict error.

I believe the current workaround is to use Slack::Messages::Formatting.markdown or some other conversion process.

Is this an intentional gap in the API? Happy to raise a PR to amend if not.

[dblock]

This looks like a bug - did they just recently add markdown_text? I think the change should go into https://github.com/dblock/slack-api-ref/blob/eb27145fe0d79fc3901de9fa4823f038bf3b88db/methods/_patches/chat/chat.postMessage.json#L4. There might be other places where this needs to be fixed, too, appreciate a PR.

[brendo]

Hmm, judging by the blame, the first mentions of markdown_text were added back in February via #524.

I'll take a swing at a PR shortly.

[brendo]

I think slack-ruby/slack-api-ref#81 should do the trick.