Prefer ale_root option when detecting roots

ale_linters/python/pylsp.vim

@@ -36,7 +36,7 @@ function! ale_linters#python#pylsp#GetCwd(buffer) abort
     \   'name': 'pylsp',
     \   'project_root': function('ale#python#FindProjectRoot'),
     \}
-    let l:root = ale#lsp_linter#FindProjectRoot(a:buffer, l:fake_linter)
+    let l:root = ale#linter#GetRoot(a:buffer, l:fake_linter)
 
     return !empty(l:root) ? l:root : v:null
 endfunction

ale_linters/python/pyright.vim

@@ -13,7 +13,7 @@ function! ale_linters#python#pyright#GetCwd(buffer) abort
     \   'name': 'pyright',
     \   'project_root': function('ale#python#FindProjectRoot'),
     \}
-    let l:root = ale#lsp_linter#FindProjectRoot(a:buffer, l:fake_linter)
+    let l:root = ale#linter#GetRoot(a:buffer, l:fake_linter)
 
     return !empty(l:root) ? l:root : v:null
 endfunction

autoload/ale/assert.vim

@@ -216,7 +216,7 @@ endfunction
 function! ale#assert#LSPProject(expected_root) abort
     let l:buffer = bufnr('')
     let l:linter = s:GetLinter()
-    let l:root = ale#lsp_linter#FindProjectRoot(l:buffer, l:linter)
+    let l:root = ale#linter#GetRoot(l:buffer, l:linter)
 
     AssertEqual a:expected_root, l:root
 endfunction

autoload/ale/linter.vim

@@ -447,3 +447,32 @@ function! ale#linter#GetAddress(buffer, linter) abort
 
     return type(l:Address) is v:t_func ? l:Address(a:buffer) : l:Address
 endfunction
+
+" Get the project root for a linter.
+" If |b:ale_root| or |g:ale_root| is set to either a String or a Dict mapping
+" linter names to roots or callbacks, return that value immediately.  When no
+" value is available, fall back to the linter-specific configuration.
+function! ale#linter#GetRoot(buffer, linter) abort
+    let l:buffer_ale_root = getbufvar(a:buffer, 'ale_root', {})
+
+    if type(l:buffer_ale_root) is v:t_string
+        return l:buffer_ale_root
+    endif
+
+    if has_key(l:buffer_ale_root, a:linter.name)
+        let l:Root = l:buffer_ale_root[a:linter.name]
+        return type(l:Root) is v:t_func ? l:Root(a:buffer) : l:Root
+    endif
+
+    if has_key(g:ale_root, a:linter.name)
+        let l:Root = g:ale_root[a:linter.name]
+        return type(l:Root) is v:t_func ? l:Root(a:buffer) : l:Root
+    endif
+
+    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 ''
+endfunction

autoload/ale/lsp_linter.vim

@@ -296,44 +296,6 @@ function! ale#lsp_linter#GetConfig(buffer, linter) abort
     return {}
 endfunction
 
-function! ale#lsp_linter#FindProjectRoot(buffer, linter) abort
-    let l:buffer_ale_root = getbufvar(a:buffer, 'ale_root', {})
-
-    if type(l:buffer_ale_root) is v:t_string
-        return l:buffer_ale_root
-    endif
-
-    " Try to get a buffer-local setting for the root
-    if has_key(l:buffer_ale_root, a:linter.name)
-        let l:Root = l:buffer_ale_root[a:linter.name]
-
-        if type(l:Root) is v:t_func
-            return l:Root(a:buffer)
-        else
-            return l:Root
-        endif
-    endif
-
-    " Try to get a global setting for the root
-    if has_key(g:ale_root, a:linter.name)
-        let l:Root = g:ale_root[a:linter.name]
-
-        if type(l:Root) is v:t_func
-            return l:Root(a:buffer)
-        else
-            return l:Root
-        endif
-    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
 
 " This function is accessible so tests can call it.
 function! ale#lsp_linter#OnInit(linter, details, Callback) abort
@@ -504,7 +466,7 @@ endfunction
 function! ale#lsp_linter#StartLSP(buffer, linter, Callback) abort
     let l:command = ''
     let l:address = ''
-    let l:root = ale#lsp_linter#FindProjectRoot(a:buffer, a:linter)
+    let l:root = ale#linter#GetRoot(a:buffer, a:linter)
 
     if empty(l:root) && a:linter.lsp isnot# 'tsserver'
         " If there's no project root, then we can't check files with LSP,

autoload/ale/python.vim

@@ -61,6 +61,12 @@ endfunction
 " through paths, including the current directory, until no __init__.py files
 " is found.
 function! ale#python#FindProjectRoot(buffer) abort
+    let l:root = ale#linter#GetRoot(a:buffer, {'name': 'python'})
+
+    if !empty(l:root)
+        return l:root
+    endif
+
     let l:ini_root = ale#python#FindProjectRootIni(a:buffer)
 
     if !empty(l:ini_root)

doc/ale-python.txt

@@ -55,6 +55,9 @@ For some linters, ALE will search for a Python project root by looking at the
 files in directories on or above where a file being checked is. ALE applies
 the following methods, in order:
 
+If |g:ale_root| or |b:ale_root| provides a value, that value is used as the
+project root instead and the searching described below is skipped.
+
 1. Find the first directory containing a common Python configuration file.
 2. If no configuration file can be found, use the first directory which does
    not contain a readable file named `__init__.py`.

doc/ale.txt

@@ -2297,17 +2297,18 @@ g:ale_root
   Type: |Dictionary| or |String|
   Default: `{}`
 
-  This option is used to determine the project root for a linter. If the value
-  is a |Dictionary|, it maps a linter to either a |String| containing the
-  project root or a |Funcref| to call to look up the root. The |Funcref| is
-  provided the buffer number as its argument.
+  This option is used to determine the project root for a linter. When set to a
+  |String| it will be used for all linters. When set to a |Dictionary|, the
+  keys are linter names and the values are either |Strings| containing project
+  roots or |Funcref|s which are passed the buffer number.
 
-  The buffer-specific variable may additionally be a string containing the
+  The buffer-specific variable may additionally be a |String| containing the
   project root itself.
 
-  If neither variable yields a result, a linter-specific function is invoked to
-  detect a project root. If this, too, yields no result, and the linter is an
-  LSP linter, it will not run.
+  If a value can be found from either variable, ALE uses it directly and skips
+  searching for a project root. If no value is found, a linter-specific
+  function is invoked to detect a project root. If this, too, yields no result
+  and the linter is an LSP linter, it will not run.
 
                                                       *ale-options.save_hidden*
                                                             *g:ale_save_hidden*

test/test_linter_defintion_processing.vader

@@ -407,7 +407,7 @@ Execute(PreProcess should allow the `project_root` to be set as a String):
   \ 'project_root': '/foo/bar',
   \})
 
-  AssertEqual '/foo/bar', ale#lsp_linter#FindProjectRoot(0, g:linter)
+  AssertEqual '/foo/bar', ale#linter#GetRoot(0, g:linter)
 
 Execute(PreProcess should `project_root` be set as a Function):
   let g:linter = ale#linter#PreProcess('testft', {
@@ -418,7 +418,7 @@ Execute(PreProcess should `project_root` be set as a Function):
   \ 'project_root': {-> '/foo/bar'},
   \})
 
-  AssertEqual '/foo/bar', ale#lsp_linter#FindProjectRoot(0, g:linter)
+  AssertEqual '/foo/bar', ale#linter#GetRoot(0, g:linter)
 
 Execute(PreProcess should complain when `project_root` is invalid):
   AssertThrows call ale#linter#PreProcess('testft', {

test/test_python_root_option.vader

@@ -0,0 +1,27 @@
+Before:
+  Save g:ale_root
+  Save b:ale_root
+  call ale#test#SetDirectory('/testplugin/test')
+
+After:
+  Restore
+  call ale#test#RestoreDirectory()
+
+Execute(The global setting is used as the project root):
+  let g:ale_root = '/foo/python'
+  call ale#test#SetFilename('test-files/python/no_virtualenv/subdir/foo/bar.py')
+  AssertEqual '/foo/python', ale#python#FindProjectRoot(bufnr(''))
+
+Execute(The buffer setting overrides the global setting):
+  let g:ale_root = '/foo/python'
+  let b:ale_root = '/bar/python'
+  call ale#test#SetFilename('test-files/python/no_virtualenv/subdir/foo/bar.py')
+  AssertEqual '/bar/python', ale#python#FindProjectRoot(bufnr(''))
+
+Execute(Fallback to searching when no setting is used):
+  unlet! g:ale_root
+  unlet! b:ale_root
+  call ale#test#SetFilename('test-files/python/no_virtualenv/subdir/foo/bar.py')
+  AssertEqual \
+  \ ale#path#Simplify(g:dir . '/../test-files/python/no_virtualenv/subdir'),
+  \ ale#python#FindProjectRoot(bufnr(''))