[READY] Migrate to GOPLS

[bstaletic]

It took a while, but it should work now. The gopls commit is pinned, because go get -u breaks daily.

Supports:

• Completion
• Diagnostics
• Format (but only whole file)
• GoTo
• GoToDefintion
• GoToDeclaration (via GoToDefinition)
• GoToType
• RestartServer
• FixIt*

Limitations:

• If any parent directory is named test_data, gopls doesn't work. This is a feature!
• If the file being edited isn't in a module or in the $GOPATH, gopls won't be able to parse it.
• If the file is inside a module directory or inside $GOPATH but doesn't obey domain/owner/project directory hierarchy, gopls won't work.
• If the hierarchy is correct, but the file that declares package foo isn't in directory domain/owner/project/foo, gopls won't work.

This is all in line with the standard golang project structure, but it means that a quick vim foo.go is impossible.

Fixes #1217

* Fixits behave od. gopls really wants to format the code even if it is unrelated to the actual FixIt reported. (check what the Subocommands_FixIt_Simple_test() is doing).

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This change is 

[puremourning]

I love the amount of code this removes.

But I don't love the limitations. As is normal for me, I use go in literally ONE project. I'd like to see if this works with that project as a sample-of-one test.

Reviewed 25 of 25 files at r1.
Reviewable status: 0 of 2 LGTMs obtained (waiting on @bstaletic)

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.gitmodules, line 46 at r1 (raw file):

	path = third_party/requests_deps/idna
	url = https://github.com/kjd/idna
[submodule "third_party/go/src/golang.org/x/tools"]

what does the 'x' mean ?

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ycmd/completers/go/go_completer.py, line 90 at r1 (raw file):

  def GetType( self, request_data ):
    # Quite stupidly, gopls returns this as markdown

Do we correctly declare the supported types of markup? IIRC there is/was a bug that we declared it wrong, that I fixed, but may or may not have actually pushed the fix for. But ultimately, markdown is better than HTML or some other nonsense.

[bstaletic]

But I don't love the limitations. As is normal for me, I use go in literally ONE project. I'd like to see if this works with that project as a sample-of-one test.

This sounds very reasonable, though keep in mind that the conversion to modules is easy, provided that the project always obeyed the standard directory hierarchy.

Reviewable status: 0 of 2 LGTMs obtained (waiting on @puremourning)

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.gitmodules, line 46 at r1 (raw file):

Previously, puremourning (Ben Jackson) wrote…

what does the 'x' mean ?

That's the "owner" in "domain/owner/project" I mentioned. It's where golang keeps a bunch of repos: https://godoc.org/-/subrepo

Needs to match the upstream repo hierarchy so we can build anything from the tools with just go build and avoid fiddling with $GOPATH. (Not to mention that the old way of setting $GOPATH somehow failed to work.

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ycmd/completers/go/go_completer.py, line 90 at r1 (raw file):

Previously, puremourning (Ben Jackson) wrote…

Do we correctly declare the supported types of markup? IIRC there is/was a bug that we declared it wrong, that I fixed, but may or may not have actually pushed the fix for. But ultimately, markdown is better than HTML or some other nonsense.

This is a stale comment. GOPLS now obeys that we didn't declare the markdown capability. I.e. it returns plain text.

Comment removed.

[codecov]

Codecov Report

Merging #1243 into master will decrease coverage by 0.01%.
The diff coverage is 88.23%.

@@            Coverage Diff             @@
##           master    #1243      +/-   ##
==========================================
- Coverage   97.42%   97.41%   -0.02%     
==========================================
  Files          95       95              
  Lines        7389     7262     -127     
  Branches      153      153              
==========================================
- Hits         7199     7074     -125     
+ Misses        149      147       -2     
  Partials       41       41

[bstaletic]

Turns out gopls supports FixIts, so added support for that.

Though, it behaves weird. It really wants to format the code even if it is unrelated to the actual FixIt reported. (check what the Subocommands_FixIt_Simple_test() is doing).

[rajathagasthya]

Any ETA on this? Looking forward to trying out Gopls with YCM.

[bstaletic]

You can always merge it locally. ETA is whenver it gets reviewed.

To merge it locally, you need to do the following:

• cd YouCompleteMe/third_party/ycmd
• git fetch origin +refs/pull/1243/merge:gopls
• git checkout gopls
• git submodule update --init --recursive
• ./build.py --skip-build --go-completer

[orlangure]

To merge it locally, you need to do the following:

@bstaletic, this does not seem to work, I'm still seeing gocode processes started by the plugin. Do I need to add anything to configuration to make the switch?

[mjolk]

@orlangure after git fetch ... you need to run git checkout gopls, then run git submodule update ... etc
@bstaletic great work! thanks!

[orlangure]

after git fetch ... you need to run git checkout gopls, then run git submodule update

@mjolk, thanks, I see now that the original comment was also edited.
@bstaletic works great, thank you!

[puremourning]

• Deletes a LOAD of code
• Seems to be strong community support
• Re-uses the language server implementation
• Tests are passing
• Code looks good.

What's not to like.

Reviewed 5 of 5 files at r3.
Reviewable status: 1 of 2 LGTMs obtained

[preslavmihaylov]

This is great. I just ran into the problem fixed by this MR and was about to open a new issue.

Can't wait for the final LGTM to approve this and get it merged.

[puremourning]

Ship It.

Multiple users have expressed interest in this PR and I have reviewed it. It net reduces our code and thus liability and increases functionality for users.

[mergify]

Thanks for sending a PR!

[bstaletic]

Rebased and fixed the tests after rebase.

Reviewable status: 0 of 2 LGTMs obtained (and 1 stale) (waiting on @puremourning)

[puremourning]

Reviewed 6 of 6 files at r4.
Reviewable status: 1 of 2 LGTMs obtained

[mergify]

Thanks for sending a PR!

[bstaletic]

For everyone watching this thread... I messed up the rebase and we have merged a broken completer. #1257 fixes this and it's literally a two character fix.