JSON WS GUI is not permitting blank themeDisplay value for get-article-content, even though it is permissible via curl

• Type: Bug
• Status: Closed
• Resolution: Duplicate
• Affects Version/s: 7.0.0 DXP FP26, 7.0.X, Master
• Fix Version/s: None
• Component/s: Web Services > JSON WS
• Labels:
  • ee-ts
  • jp-support
• Fix Priority: 3
• Git Pull Request: https://github.com/gregory-bretall/liferay-portal/pull/29

While attempting to test /journal.journalarticle/get-article-content through JSON WS's GUI form, we cannot pass a blank value for themeDisplay.

When we try to pass the values through the UI, we get an error:
"Conversion failed: com.liferay.portal.kernel.theme.ThemeDisplay"

However, when we can pass a blank value using curl or URL by setting -theme-display:

curl http://localhost:8080/api/jsonws/journal.journalarticle/get-article-content \
  -u [email protected]:test \
  -d groupId=20143 \
  -d articleId='37320' \
  -d languageId='en-US' \
  -d -themeDisplay=

In practice, if we run this, it'll return with the article:

$ curl http://localhost:8080/api/jsonws/journal.journalarticle/get-article-content \
>   -u [email protected]:test \
>   -d groupId=20143 \
>   -d articleId='37320' \
>   -d languageId='en-US' \
>   -d -themeDisplay=

"<p>Test Data<\/p>"

Steps to Reproduce
1. Start up Liferay DXP + FP26
2. In a new window, note the Liferay DXP (default site)'s GroupID
3. Create a new article in Web Content in Liferay DXP (default site), and note its article ID
4. Access JSON WS, and go to the get-article-content-4 method: http://localhost:8080/api/jsonws?contextName=journal&signature=%2Fjournal.journalarticle%2Fget-article-content-4-groupId-articleId-languageId-themeDisplay
5. Fill in the form with the details found in steps 2-4 (en_US for languageId), and leave the themeDisplay blank

Result
"Conversion failed: com.liferay.portal.kernel.theme.ThemeDisplay"

However, if we try the curl example as listed in the description above (where we set -themeDisplay), it works fine.