Storing Markdown in a Yesod Persist Model

I am trying to store markdown on a field in Persistent model with a MySQL backend. I messed up the use case:

models:

TestModel
    content Markdown

      

        
        
        
      

    

Model.hs:

import Text.Markdown (Markdown)
import Yesod.Text.Markdown ()
....

      

        
        
        
      

    

This seems to create the correct migrations:

mysql> show columns in test_model;
+---------+------------+------+-----+---------+----------------+
| Field   | Type       | Null | Key | Default | Extra          |
+---------+------------+------+-----+---------+----------------+
| id      | bigint(20) | NO   | PRI | NULL    | auto_increment |
| content | text       | NO   |     | NULL    |                |
+---------+------------+------+-----+---------+----------------+

      

        
        
        
      

    

However, when I try to fetch data from this table, I get an exception. Below is an example from cabal repl

, but the same happens when the application starts:

repl> testid <- db $ insert $ TestModel $ Markdown "# Hello world"
[Debug#SQL] INSERT INTO `test_model`(`content`) VALUES(?); [PersistText "# Hello world"]
repl> testmodel <- db $ get testid
[Debug#SQL] SELECT `content` FROM `test_model` WHERE `id`=?; [PersistInt64 2]
*** Exception: runFakeHandler issue: InternalError "get TestModelKey {unTestModelKey = SqlBackendKey {unSqlBackendKey = 2}}: field content: Not a PersistText value"

      

        
        
        
      

    

My first guess was that the TestModel constructor value was wrong, but the same error occurs even when creating an object using markdownField

in the form:

testModelForm :: AForm Handler TestModel
testModelForm = TestModel
        <$> areq markdownField "Content" Nothing

getTestModelR :: TestModelId -> Handler Html
getTestModelR testModelId = do
    testmodel <- runDB $ get404 testModelId
....
08/Aug/2015:12:44:33 -0700 [Error#yesod-core] get TestModelKey {unTestModelKey = SqlBackendKey {unSqlBackendKey = 2}}: field content: Not a PersistText value @(yesod-core-1.4.12:Yesod.Core.Class.Yesod ./Yesod/Core/Class/Yesod.hs:577:5)

      

        
        
        
      

    

Has anyone seen this exception before and knows how to deal with it? The only documentation I could find for this error was the source code for yesod-text-markdown

.