racket: support racket-langserver lsp (#3808)

* racket: support racket-langserver lsp

* racket-langserver: find highest dir with init.rkt

* autoload/ale/racket: re-indent to 4 spaces

* racket: lint: sort supported tools

* racket: lint: function!

This is _not_ needed anymore, but the lint wants it. See :help E127

* racket-langserver: do not use new dict format

* racket: lint: use snake_case

* add tests for racket-langserver

* racket-langserver tests: correct result values

14 files changed, 85 insertions, 0 deletions

diff --git a/ale_linters/racket/langserver.vim b/ale_linters/racket/langserver.vim
new file mode 100644
index 00000000..ec80ed7b
--- /dev/null
+++ b/ale_linters/racket/langserver.vim
@@ -0,0 +1,7 @@
+call ale#linter#Define('racket', {
+\   'name': 'racket_langserver',
+\   'lsp': 'stdio',
+\   'executable': 'racket',
+\   'command': '%e -l racket-langserver',
+\   'project_root': function('ale#racket#FindProjectRoot'),
+\})
diff --git a/autoload/ale/racket.vim b/autoload/ale/racket.vim
new file mode 100644
index 00000000..ff896108
--- /dev/null
+++ b/autoload/ale/racket.vim
@@ -0,0 +1,12 @@
+function! ale#racket#FindProjectRoot(buffer) abort
+    let l:cwd = expand('#' . a:buffer . ':p:h')
+    let l:highest_init = l:cwd
+
+    for l:path in ale#path#Upwards(l:cwd)
+        if filereadable(l:path.'/init.rkt')
+            let l:highest_init = l:path
+        endif
+    endfor
+
+    return l:highest_init
+endfunction
diff --git a/doc/ale-supported-languages-and-tools.txt b/doc/ale-supported-languages-and-tools.txt
index 638cee7d..27c50efa 100644
--- a/doc/ale-supported-languages-and-tools.txt
+++ b/doc/ale-supported-languages-and-tools.txt
@@ -428,6 +428,7 @@ Notes:
   * `lintr`
   * `styler`
 * Racket
+  * `racket-langserver`
   * `raco`
 * Re:VIEW
   * `redpen`
diff --git a/supported-tools.md b/supported-tools.md
index 1b7b1de4..2a60b6d6 100644
--- a/supported-tools.md
+++ b/supported-tools.md
@@ -437,6 +437,7 @@ formatting.
   * [lintr](https://github.com/jimhester/lintr)
   * [styler](https://github.com/r-lib/styler)
 * Racket
+  * [racket-langserver](https://github.com/jeapostrophe/racket-langserver/tree/master)
   * [raco](https://docs.racket-lang.org/raco/)
 * Re:VIEW
   * [redpen](http://redpen.cc/)
diff --git a/test/linter/test_racket_langserver.vader b/test/linter/test_racket_langserver.vader
new file mode 100644
index 00000000..021eb565
--- /dev/null
+++ b/test/linter/test_racket_langserver.vader
@@ -0,0 +1,45 @@
+" Author: D. Ben Knoble <https://github.com/benknoble>
+" Description: Tests for racket-langserver lsp linter.
+Before:
+  call ale#assert#SetUpLinterTest('racket', 'langserver')
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(command callback should return default string):
+  AssertLinter 'racket', ale#Escape('racket').' -l racket-langserver'
+
+Execute(should set racket-langserver for deep module 3):
+  call ale#test#SetFilename('../test-files/racket/many-inits/a/b/c/foo.rkt')
+  AssertLSPLanguage 'racket'
+  AssertLSPOptions {}
+  AssertLSPConfig {}
+  AssertLSPProject ale#test#GetFilename('../test-files/racket/many-inits')
+
+Execute(should set racket-langserver for deep module 2):
+  call ale#test#SetFilename('../test-files/racket/many-inits/a/b/foo.rkt')
+  AssertLSPLanguage 'racket'
+  AssertLSPOptions {}
+  AssertLSPConfig {}
+  AssertLSPProject ale#test#GetFilename('../test-files/racket/many-inits')
+
+Execute(should set racket-langserver for deep module 1):
+  call ale#test#SetFilename('../test-files/racket/many-inits/a/foo.rkt')
+  AssertLSPLanguage 'racket'
+  AssertLSPOptions {}
+  AssertLSPConfig {}
+  AssertLSPProject ale#test#GetFilename('../test-files/racket/many-inits')
+
+Execute(should set racket-langserver for top-level module):
+  call ale#test#SetFilename('../test-files/racket/many-inits/foo.rkt')
+  AssertLSPLanguage 'racket'
+  AssertLSPOptions {}
+  AssertLSPConfig {}
+  AssertLSPProject ale#test#GetFilename('../test-files/racket/many-inits')
+
+Execute(should set racket-langserver for non-package module or script):
+  call ale#test#SetFilename('../test-files/racket/simple-script/foo.rkt')
+  AssertLSPLanguage 'racket'
+  AssertLSPOptions {}
+  AssertLSPConfig {}
+  AssertLSPProject ale#test#GetFilename('../test-files/racket/simple-script')
diff --git a/test/test-files/racket/many-inits/a/b/c/foo.rkt b/test/test-files/racket/many-inits/a/b/c/foo.rkt
new file mode 100644
index 00000000..622f3eea
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/b/c/foo.rkt
@@ -0,0 +1,3 @@
+#lang racket/base
+
+(displayln "foo")
diff --git a/test/test-files/racket/many-inits/a/b/c/init.rkt b/test/test-files/racket/many-inits/a/b/c/init.rkt
new file mode 100644
index 00000000..e0c94f27
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/b/c/init.rkt
@@ -0,0 +1 @@
+#lang info
diff --git a/test/test-files/racket/many-inits/a/b/foo.rkt b/test/test-files/racket/many-inits/a/b/foo.rkt
new file mode 100644
index 00000000..622f3eea
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/b/foo.rkt
@@ -0,0 +1,3 @@
+#lang racket/base
+
+(displayln "foo")
diff --git a/test/test-files/racket/many-inits/a/b/init.rkt b/test/test-files/racket/many-inits/a/b/init.rkt
new file mode 100644
index 00000000..e0c94f27
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/b/init.rkt
@@ -0,0 +1 @@
+#lang info
diff --git a/test/test-files/racket/many-inits/a/foo.rkt b/test/test-files/racket/many-inits/a/foo.rkt
new file mode 100644
index 00000000..622f3eea
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/foo.rkt
@@ -0,0 +1,3 @@
+#lang racket/base
+
+(displayln "foo")
diff --git a/test/test-files/racket/many-inits/a/init.rkt b/test/test-files/racket/many-inits/a/init.rkt
new file mode 100644
index 00000000..e0c94f27
--- /dev/null
+++ b/test/test-files/racket/many-inits/a/init.rkt
@@ -0,0 +1 @@
+#lang info
diff --git a/test/test-files/racket/many-inits/foo.rkt b/test/test-files/racket/many-inits/foo.rkt
new file mode 100644
index 00000000..622f3eea
--- /dev/null
+++ b/test/test-files/racket/many-inits/foo.rkt
@@ -0,0 +1,3 @@
+#lang racket/base
+
+(displayln "foo")
diff --git a/test/test-files/racket/many-inits/init.rkt b/test/test-files/racket/many-inits/init.rkt
new file mode 100644
index 00000000..e0c94f27
--- /dev/null
+++ b/test/test-files/racket/many-inits/init.rkt
@@ -0,0 +1 @@
+#lang info
diff --git a/test/test-files/racket/simple-script/foo.rkt b/test/test-files/racket/simple-script/foo.rkt
new file mode 100644
index 00000000..622f3eea
--- /dev/null
+++ b/test/test-files/racket/simple-script/foo.rkt
@@ -0,0 +1,3 @@
+#lang racket/base
+
+(displayln "foo")