The core near match implementation already converts input to NFKC, where U+FF1A becomes U+003A. Therefore Wikipedia：首页 or 维基百科：首页 can currently resolve to Wikipedia:首页 with srwhat=nearmatch.

The completion suggester and fulltext search do not appear to work for the U+FF1A cases on surface, because by default they work in the article namespace. Dealing with this case can be tricky, as shown by the book title https://en.wikipedia.org/wiki/Wikipedia_–_The_Missing_Manual. It might not be appropriate to assume a query starting with 维基百科： is searching either the article namespace or the Wikipedia namespace. It might need to recognize both interpretations, and probably needs some refactoring on the CirrusSearch side.

If this ambiguity is dismissed by assuming 维基百科： to be a legitimate namespace prefix for search purposes, it should be simple to implement.

In T432820#12329596, @Bewfip wrote:

The core near match implementation already converts input to NFKC, where U+FF1A becomes U+003A. Therefore Wikipedia：首页 or 维基百科：首页 can currently resolve to Wikipedia:首页 with srwhat=nearmatch.

The completion suggester and fulltext search do not appear to work for the U+FF1A cases on surface, because by default they work in the article namespace. Dealing with this case can be tricky, as shown by the book title https://en.wikipedia.org/wiki/Wikipedia_–_The_Missing_Manual. It might not be appropriate to assume a query starting with 维基百科： is searching either the article namespace or the Wikipedia namespace. It might need to recognize both interpretations, and probably needs some refactoring on the CirrusSearch side.

If this ambiguity is dismissed by assuming 维基百科： to be a legitimate namespace prefix for search purposes, it should be simple to implement.

For that "Wikipedia – The Missing Manual" case, the English Wikipedia has a redirect at "Wikipedia:The Missing Manual". We should create that kind of redirects if possible when we encounter those technical restrictions, so I guess searching only in the Wikipedia namespace is fair enough.