If you update to Xtext 2.27.0 and have compiler tests for your Xbase DSL that assert the output of the compilation, you’ll get lots of failures after the update.

I am guilty of that
Well, for a good reason, at least

In fact, I worked on this issue: https://github.com/eclipse/xtext-extras/issues/772 and its fix is included in Xtext 2.27.0.

Now, the Xbase compilation mechanism does not generate useless empty lines anymore (before, it added lines with two spaces). Your compiler tests will fail because the output is different.

I personally fixed my tests in my DSLs by simply using the Find/Replace mechanism of Eclipse with this substitution pattern (there are two space characters between the tab character and the newline character):

If you have deep nesting in your compilation output, you might have to repeat this substitution with more than two characters, but this should not be required unless you generate nested classes or something like that.

With the above substitution a test like the following one:

will become like the following one (you see the difference: no empty line with two characters between the two generated constructors:

Now your tests should be fixed