Suggest functions for fixing issues for ALEFix

autoload/ale/fix.vim

@@ -249,7 +249,7 @@ function! s:GetCallbacks() abort
     endfor
 
     if empty(l:callback_list)
-        echoerr 'No fixers have been defined for filetype: ' . &filetype
+        echoerr 'No fixers have been defined. Try :ALEFixSuggest'
         return []
     endif
 

autoload/ale/fix/registry.vim

@@ -37,6 +37,11 @@ endfunction
 " Set up entries now.
 call ale#fix#registry#ResetToDefaults()
 
+" Remove everything from the registry, useful for tests.
+function! ale#fix#registry#Clear() abort
+    let s:entries = {}
+endfunction
+
 " Add a function for fixing problems to the registry.
 function! ale#fix#registry#Add(name, func, filetypes, desc) abort
     if type(a:name) != type('')
@@ -72,3 +77,58 @@ endfunction
 function! ale#fix#registry#GetFunc(name) abort
     return get(s:entries, a:name, {'function': ''}).function
 endfunction
+
+function! s:ShouldSuggestForType(suggested_filetypes, type_list) abort
+    for l:type in a:type_list
+        if index(a:suggested_filetypes, l:type) >= 0
+            return 1
+        endif
+    endfor
+
+    return 0
+endfunction
+
+" Suggest functions to use from the registry.
+function! ale#fix#registry#Suggest(filetype) abort
+    let l:type_list = split(a:filetype, '\.')
+    let l:first_for_filetype = 1
+    let l:first_generic = 1
+
+    for l:key in sort(keys(s:entries))
+        let l:suggested_filetypes = s:entries[l:key].suggested_filetypes
+
+        if s:ShouldSuggestForType(l:suggested_filetypes, l:type_list)
+            if l:first_for_filetype
+                let l:first_for_filetype = 0
+                echom 'Try the following fixers appropriate for the filetype:'
+                echom ''
+            endif
+
+            echom printf('%s - %s', string(l:key), s:entries[l:key].description)
+        endif
+    endfor
+
+
+    for l:key in sort(keys(s:entries))
+        if empty(s:entries[l:key].suggested_filetypes)
+            if l:first_generic
+                if !l:first_for_filetype
+                    echom ''
+                endif
+
+                let l:first_generic = 0
+                echom 'Try the following generic fixers:'
+                echom ''
+            endif
+
+            echom printf('%s - %s', string(l:key), s:entries[l:key].description)
+        endif
+    endfor
+
+    if l:first_for_filetype && l:first_generic
+        echom 'There is nothing in the registry to suggest.'
+    else
+        echom ''
+        echom 'See :help ale-fix-configuration'
+    endif
+endfunction

plugin/ale.vim

@@ -281,6 +281,8 @@ command! -bar ALEInfoToClipboard :call ale#debugging#InfoToClipboard()
 
 " Fix problems in files.
 command! -bar ALEFix :call ale#fix#Fix()
+" Suggest registered functions to use for fixing problems.
+command! -bar ALEFixSuggest :call ale#fix#registry#Suggest(&filetype)
 
 " <Plug> mappings for commands
 nnoremap <silent> <Plug>(ale_previous) :ALEPrevious<Return>

test/test_ale_fix.vader

@@ -53,7 +53,7 @@ Given testft (A file with three lines):
 
 Execute(ALEFix should complain when there are no functions to call):
   AssertThrows ALEFix
-  AssertEqual 'Vim(echoerr):No fixers have been defined for filetype: testft', g:vader_exception
+  AssertEqual 'Vim(echoerr):No fixers have been defined. Try :ALEFixSuggest', g:vader_exception
 
 Execute(ALEFix should apply simple functions):
   let g:ale_fixers.testft = ['AddCarets']

test/test_ale_fix_suggest.vader

@@ -0,0 +1,75 @@
+Before:
+  call ale#fix#registry#Clear()
+
+  function GetSuggestions()
+    redir => l:output
+      silent ALEFixSuggest
+    redir END
+
+    return split(l:output, "\n")
+  endfunction
+
+After:
+  call ale#fix#registry#ResetToDefaults()
+  delfunction GetSuggestions
+
+Execute(ALEFixSuggest should return something sensible with no suggestions):
+  AssertEqual
+  \ [
+  \   'There is nothing in the registry to suggest.',
+  \ ],
+  \ GetSuggestions()
+
+Execute(ALEFixSuggest output should be correct for only generic handlers):
+  call ale#fix#registry#Add('zed', 'XYZ', [], 'Zedify things.')
+  call ale#fix#registry#Add('alpha', 'XYZ', [], 'Alpha things.')
+
+  AssertEqual
+  \ [
+  \   'Try the following generic fixers:',
+  \   '',
+  \   '''alpha'' - Alpha things.',
+  \   '''zed'' - Zedify things.',
+  \   '',
+  \   'See :help ale-fix-configuration',
+  \ ],
+  \ GetSuggestions()
+
+Execute(ALEFixSuggest output should be correct for only filetype handlers):
+  let &filetype = 'testft2.testft'
+
+  call ale#fix#registry#Add('zed', 'XYZ', ['testft2'], 'Zedify things.')
+  call ale#fix#registry#Add('alpha', 'XYZ', ['testft'], 'Alpha things.')
+
+  AssertEqual
+  \ [
+  \   'Try the following fixers appropriate for the filetype:',
+  \   '',
+  \   '''alpha'' - Alpha things.',
+  \   '''zed'' - Zedify things.',
+  \   '',
+  \   'See :help ale-fix-configuration',
+  \ ],
+  \ GetSuggestions()
+
+Execute(ALEFixSuggest should suggest filetype and generic handlers):
+  let &filetype = 'testft2.testft'
+
+  call ale#fix#registry#Add('zed', 'XYZ', ['testft2'], 'Zedify things.')
+  call ale#fix#registry#Add('alpha', 'XYZ', ['testft'], 'Alpha things.')
+  call ale#fix#registry#Add('generic', 'XYZ', [], 'Generic things.')
+
+  AssertEqual
+  \ [
+  \   'Try the following fixers appropriate for the filetype:',
+  \   '',
+  \   '''alpha'' - Alpha things.',
+  \   '''zed'' - Zedify things.',
+  \   '',
+  \   'Try the following generic fixers:',
+  \   '',
+  \   '''generic'' - Generic things.',
+  \   '',
+  \   'See :help ale-fix-configuration',
+  \ ],
+  \ GetSuggestions()