#2132 - Implement project_root as a replacement for project_root_callback

autoload/ale/linter.vim

@@ -242,10 +242,21 @@ function! ale#linter#PreProcess(filetype, linter) abort
             endif
         endif
 
-        let l:obj.project_root_callback = get(a:linter, 'project_root_callback')
+        if has_key(a:linter, 'project_root')
+            let l:obj.project_root = a:linter.project_root
 
-        if !s:IsCallback(l:obj.project_root_callback)
-            throw '`project_root_callback` must be a callback for LSP linters'
+            if type(l:obj.project_root) isnot v:t_string
+            \&& type(l:obj.project_root) isnot v:t_func
+                throw '`project_root` must be a String or Function if defined'
+            endif
+        elseif has_key(a:linter, 'project_root_callback')
+            let l:obj.project_root_callback = a:linter.project_root_callback
+
+            if !s:IsCallback(l:obj.project_root_callback)
+                throw '`project_root_callback` must be a callback if defined'
+            endif
+        else
+            throw '`project_root` or `project_root_callback` must be defined for LSP linters'
         endif
 
         if has_key(a:linter, 'completion_filter')

autoload/ale/lsp_linter.vim

@@ -194,6 +194,12 @@ function! ale#lsp_linter#FindProjectRoot(buffer, linter) abort
     endif
 
     " Fall back to the linter-specific configuration
+    if has_key(a:linter, 'project_root')
+        let l:Root = a:linter.project_root
+
+        return type(l:Root) is v:t_func ? l:Root(a:buffer) : l:Root
+    endif
+
     return ale#util#GetFunction(a:linter.project_root_callback)(a:buffer)
 endfunction
 

doc/ale.txt

@@ -3270,16 +3270,21 @@ ale#linter#Define(filetype, linter)                       *ale#linter#Define()*
                          This argument must only be set if the `lsp` argument
                          is set to `'socket'`.
 
-  `project_root_callback`  A |String| or |Funcref| for a callback function
-                         accepting a buffer number. A |String| should be
-                         returned representing the path to the project for the
-                         file being checked with the language server. If an
-                         empty string is returned, the file will not be
+  `project_root`           A |String| representing a path to the project for
+                         the file being checked with the language server, or
+                         a |Funcref| accepting a buffer number and returning
+                         the |String|.
+
+                         If an empty string is returned, the file will not be
                          checked at all.
 
                          This argument must only be set if the `lsp` argument
                          is also set to a non-empty string.
 
+  `project_root_callback`  A |String| or |Funcref| for a callback function
+                         accepting a buffer number and returning the
+                         `project_root` |String| as documented above.
+
   `language`               A |String| representing the name of the language
                          being checked, or a |Funcref| accepting a buffer
                          number and returning the |String|. This string will

test/test_linter_defintion_processing.vader

@@ -1,4 +1,10 @@
 Before:
+  Save g:ale_lsp_root
+  Save b:ale_lsp_root
+
+  let g:ale_lsp_root = {}
+  unlet! b:ale_lsp_root
+
   let g:linter = {}
 
 After:
@@ -558,6 +564,68 @@ Execute(PreProcess should complain about invalid address values):
   \})
   AssertEqual '`address` must be a String or Function if defined', g:vader_exception
 
+Execute(PreProcess should accept allow the project root be set as a String):
+  let g:linter = ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root': '/foo/bar',
+  \})
+
+  AssertEqual '/foo/bar', ale#lsp_linter#FindProjectRoot(0, g:linter)
+
+Execute(PreProcess should accept allow the project root be set as a Function):
+  let g:linter = ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root': {-> '/foo/bar'},
+  \})
+
+  AssertEqual '/foo/bar', ale#lsp_linter#FindProjectRoot(0, g:linter)
+
+Execute(PreProcess should complain when the project_root valid is invalid):
+  AssertThrows call ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root': 0,
+  \})
+  AssertEqual '`project_root` must be a String or Function if defined', g:vader_exception
+
+Execute(PreProcess should accept project_root_callback as a String):
+  call ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root_callback': 'Foobar',
+  \})
+
+Execute(PreProcess should accept project_root_callback as a Function):
+  let g:linter = ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root_callback': {-> '/foo/bar'},
+  \})
+
+  AssertEqual '/foo/bar', ale#lsp_linter#FindProjectRoot(0, g:linter)
+
+Execute(PreProcess should complain when the project_root_callback valid is invalid):
+  AssertThrows call ale#linter#PreProcess('testft', {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address': 'foo:123',
+  \ 'language': 'x',
+  \ 'project_root_callback': 0,
+  \})
+  AssertEqual '`project_root_callback` must be a callback if defined', g:vader_exception
+
 Execute(PreProcess should complain about using initialization_options and initialization_options_callback together):
   let g:linter = {
   \ 'name': 'x',