Work with moving sequences

[tszmytka]

Currently the plugin incorrectly handles control sequences like:

• CUU Cursor Up
• CUD Cursor Down
• CUF Cursor Forward
• CUB Cursor Back
• EL Erase in Line

Using many popular tools in a job, like docker, produces output similar to:

+ docker-compose down
Stopping container_1               ... 
Stopping container_2               ... 
Stopping container_3               ... 
�[4A�[2K
Stopping container_1               done
�[4B�[2A�[2K

This PR contains a fix - the mentioned sequences will not produce any output - as well as a test case against regression.
Merging this may very well fix #151 as the actual problem looks very similar.

[dwnusbaum]

Thanks for the PR, especially for adding tests! The change seems ok to me, this is pretty much what I proposed at the end of #151 (comment).

I added one minor comment, and I think we might as well override all methods on AnsiOutputStream that are not already overridden by AnsiHtmlOutputStream at the same time to do the same thing. What do you think?

[tszmytka]

I've provided additional adjustments so closing the original conversation.

• All AnsiOutputStream methods are overridden

• Made them all call AnsiAttributeElement.Emitter#emitInvisibleSequence previously emitRedundantReset

• Restructured EmitterImpl to not rely on any special values (null or otherwise) and equipped the method param with @Nonnull. Now there is no way of anyone providing "", null or anything else and triggering the special behavior.
  I really don't like that guerilla-style EmitterImpl class defined out of nowhere in the middle of a method but changing that would require a broader refactoring.

• Added tests

@dwnusbaum what do you think?

[dwnusbaum]

@tszmytka The changes look great to me, thanks for adding tests for everything!

[dwnusbaum]

Note: This breaks binary compatibility. We could avoid it by keeping emitRedundantReset and having it call emitInvisibleSequence internally, but it doesn't look like emitRedundantReset was ever used by any other plugins, so I think the change is fine as-is.

[tszmytka]

Note: This breaks binary compatibility.

Are there other plugins extending ansicolor-plugin?

[dwnusbaum]

updatebot plugin implements AnsiAttributeElement.Emitter (the usage looks weird, it probably shouldn't be extending ansicolor), but the plugin looks obsolete and has less than 50 installs, so I think it can be ignored.

[tszmytka]

Do I need to do anything else in order to merge this?

[dwnusbaum]

@tszmytka I just merged #169, can you resolve the conflict? Once we have a passing CI build, I am happy to merge and release in the next few days (CC @dblock as a heads up).

Could you also update CHANGELOG.md in this PR with your changes?

[tszmytka]

@tszmytka I just merged #169, can you resolve the conflict? Once we have a passing CI build, I am happy to merge and release in the next few days (CC @dblock as a heads up).

Could you also update CHANGELOG.md in this PR with your changes?

@dwnusbaum All done. Thanks for the help.

[dwnusbaum]

@tszmytka Thanks for fixing the bug!