Invalid character in pages - page cannot be created

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X, 7.1.X, Master
• Fix Version/s: 7.0.0 DXP FP63, 7.0.X, 7.1.10 DXP FP3, 7.1.1 CE GA2, 7.1.10.1 SP1, 7.1.X, Master
• Component/s: Collaboration > Wiki
• Labels:
  • liferay-dxp-70-sp10
  • liferay-dxp-71-sp1
  • liferay-fixpack-de-63-7010
  • liferay-fixpack-dxp-3-7110
• Branch Version/s:
  7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Story Points: 0.25
• Fix Priority: 3
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/64147

The issue: non-breaking space in Creole source breaks the auto-linking feature of Wiki. It graphically appears as a normal space in rich text editor but it shows as a red dot in the source. Such dot is translated into %C2%A0 , breaking the hyperlink, which will lead to a non-existing page. I could reproduce on Grow Prod.

Steps on clean environment:

1) Place a Wiki portlet on a page
2) Add some content to the FrontPage
3) Add Child Page to FrontPage with title "Test Page" (with whatever content)
4) In a Google Docs, create this text: Test<non-breaking-space>Page. You may be able to type the non breaking space in a Google Doc by following these steps: Insert ->Special characters... >>Format & Whitespace + Compatibility >> Click the first empty box ((U+00A0) No-break Space) on the left
5) Edit FrontPage (or create another Child Page)
6) Copy the text to the content of the new Wiki page
7) Switch to source: notice how there is a red dot instead of space
8) Still in source mode, surround the text with double square brackets [[ ]] so that it will become an actual hyperlink like this:

**[[Test Page]]**

This should point to the already existing Wiki page http://localhost:8080/web/guest/home/-/wiki/Main/Test+Page after publication
7) Publish
8) Click on Test Page link

Expected: http://localhost:8080/web/guest/home/-/wiki/Main/Test+Page to open
Actual behavior: No existing page will open, instead you will be prompted to create a new one

Modern applications allow the usage of non breaking space. Wiki creole accepts and represents them graphically as a space, but stores them in the source as being an "error" (red dot). Such error messes the hyperlinks, leading to unwanted results.