Add kotlin language server support (#1725)

* Add kotlin languageserver linter definition
* Added kotlin languageserver references in docs, fix missing !! on other linters
* Added Vader tests for root path detection in Kotlin Language Server

1 files changed, 38 insertions, 0 deletions

diff --git a/ale_linters/kotlin/languageserver.vim b/ale_linters/kotlin/languageserver.vim
new file mode 100644
index 00000000..0ab673ec
--- /dev/null
+++ b/ale_linters/kotlin/languageserver.vim
@@ -0,0 +1,38 @@
+" Author: MTDL9 <https://github.com/MTDL9>
+" Description: Support for the Kotlin language server https://github.com/fwcd/KotlinLanguageServer
+
+call ale#Set('kotlin_languageserver_executable', 'kotlin-language-server')
+
+function! ale_linters#kotlin#languageserver#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'kotlin_languageserver_executable')
+endfunction
+
+function! ale_linters#kotlin#languageserver#GetCommand(buffer) abort
+    let l:executable = ale_linters#kotlin#languageserver#GetExecutable(a:buffer)
+    return ale#Escape(l:executable)
+endfunction
+
+function! ale_linters#kotlin#languageserver#GetProjectRoot(buffer) abort
+    let l:gradle_root = ale#gradle#FindProjectRoot(a:buffer)
+
+    if !empty(l:gradle_root)
+        return l:gradle_root
+    endif
+
+    let l:maven_pom_file = ale#path#FindNearestFile(a:buffer, 'pom.xml')
+
+    if !empty(l:maven_pom_file)
+        return fnamemodify(l:maven_pom_file, ':h')
+    endif
+
+    return ''
+endfunction
+
+call ale#linter#Define('kotlin', {
+\   'name': 'languageserver',
+\   'lsp': 'stdio',
+\   'executable_callback': 'ale_linters#kotlin#languageserver#GetExecutable',
+\   'command_callback': 'ale_linters#kotlin#languageserver#GetCommand',
+\   'language': 'kotlin',
+\   'project_root_callback': 'ale_linters#kotlin#languageserver#GetProjectRoot',
+\})