Go1.8 html/template a change in behavior

This is a created article in which the information may have evolved or changed.

During the development of Go1.8, there is a commit, the title is:

Html/template, text/template:clarify template redefinition behavior

Description is:

Make two important points clearer: - Giving a template definition containing   nothing but spaces has no effect. - Giving a template definition containing   non-spaces can only be done once per template.Fixes #16912.Fixes #16913.Fixes #17360.

It looks nothing special, but if you use some template parsing based on go template, you may encounter template hot compile after upgrading to Go1.8. Don't ask me how I know.