Add option to open loclist/quicklist when there are errors (#266)

* Add option to open loclist/quicklist when there are errors

I copied PR #137, and tries to complete it by correcting some issues and
adding vader tests.

About tests, first time with vader, can you give some feedback if there
are what you expected in PR #137.

* Remove old code + fix indent issue

* add g:ale_keep_list_window_open option

* Correct bug with keep open option

* Add comment into vader file

* Fix errors for Travis CI build

4 files changed, 156 insertions, 3 deletions

diff --git a/autoload/ale/engine.vim b/autoload/ale/engine.vim
index 933be2ac..08852e00 100644
--- a/autoload/ale/engine.vim
+++ b/autoload/ale/engine.vim
@@ -161,8 +161,8 @@ function! s:HandleExit(job) abort
     let g:ale_buffer_info[l:buffer].loclist = g:ale_buffer_info[l:buffer].new_loclist
     let g:ale_buffer_info[l:buffer].new_loclist = []
 
-    if g:ale_set_loclist
-        call setloclist(0, g:ale_buffer_info[l:buffer].loclist)
+    if g:ale_set_quickfix || g:ale_set_loclist
+        call ale#list#SetLists(g:ale_buffer_info[l:buffer].loclist)
     endif
 
     if g:ale_set_signs
diff --git a/autoload/ale/list.vim b/autoload/ale/list.vim
new file mode 100644
index 00000000..480880e4
--- /dev/null
+++ b/autoload/ale/list.vim
@@ -0,0 +1,49 @@
+" Author: Bjorn Neergaard <bjorn@neersighted.com>, modified by Yann fery <yann@fery.me>
+" Description: Manages the loclist and quickfix lists
+
+" Return 1 if there is a buffer with buftype == 'quickfix' in bufffer list
+function! ale#list#IsQuickfixOpen() abort
+    for l:buf in range(1, bufnr('$'))
+        if getbufvar(l:buf, '&buftype') ==# 'quickfix' 
+            return 1
+        endif
+    endfor
+    return 0 
+endfunction
+
+function! ale#list#SetLists(loclist) abort
+    if g:ale_set_quickfix
+        call setqflist(a:loclist)
+    elseif g:ale_set_loclist
+        call setloclist(0, a:loclist)
+    endif
+
+    " If we don't auto-open lists, bail out here.
+    if !g:ale_open_list && !g:ale_keep_list_window_open
+        return
+    endif
+
+    " If we have errors in our list, open the list. Only if it isn't already open
+    if len(a:loclist) > 0 || g:ale_keep_list_window_open
+        let l:winnr = winnr()
+
+        if g:ale_set_quickfix
+            copen
+        elseif g:ale_set_loclist
+            lopen
+        endif
+
+        " If focus changed, restore it (jump to the last window).
+        if l:winnr !=# winnr()
+            wincmd p
+        endif
+
+        " Only close if the list is totally empty (relying on Vim's state, not our
+        " own). This keeps us from closing the window when other plugins have
+        " populated it.
+    elseif !g:ale_keep_list_window_open && g:ale_set_quickfix && len(getqflist()) == 0
+        cclose
+    elseif !g:ale_keep_list_window_open && len(getloclist(0)) == 0
+        lclose
+    endif
+endfunction
diff --git a/plugin/ale.vim b/plugin/ale.vim
index 9d2f62c1..cb90aac8 100644
--- a/plugin/ale.vim
+++ b/plugin/ale.vim
@@ -74,8 +74,16 @@ if g:ale_lint_on_save
     augroup END
 endif
 
-" This flag can be set to 0 to disable setting the loclist.
+" These flags dictates if ale uses the quickfix or the loclist (loclist is the
+" default, quickfix overrides loclist).
 let g:ale_set_loclist = get(g:, 'ale_set_loclist', 1)
+let g:ale_set_quickfix = get(g:, 'ale_set_quickfix', 0)
+
+" This flag dictates if ale open the configured loclist 
+let g:ale_open_list = get(g:, 'ale_open_list', 0)
+
+" This flag dictates if ale keeps open loclist even if there is no error in loclist
+let g:ale_keep_list_window_open = get(g:, 'ale_keep_list_window_open', 0)
 
 " This flag can be set to 0 to disable setting signs.
 " This is enabled by default only if the 'signs' feature exists.
diff --git a/test/test_loclist_quicklist.vader b/test/test_loclist_quicklist.vader
new file mode 100644
index 00000000..e3a47a4e
--- /dev/null
+++ b/test/test_loclist_quicklist.vader
@@ -0,0 +1,96 @@
+" Author: Yann Fery <yann@fery.me>
+
+Before:
+  let g:loclist = [
+  \ {'lnum': 5, 'col': 5},
+  \ {'lnum': 5, 'col': 4},
+  \ {'lnum': 2, 'col': 10},
+  \ {'lnum': 3, 'col': 2},
+  \]
+  let g:empty_loclist = []
+
+After:
+  " Close quickfix window after every execute block
+  lcl
+  ccl
+  unlet g:loclist
+  unlet g:empty_loclist
+
+Execute (IsQuickfixOpen):
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  call setloclist(0, g:loclist)
+  lopen
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  lcl
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  call setqflist(g:loclist)
+  copen
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  ccl
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  
+Execute (loclist and openlist):
+  let g:ale_set_loclist = 1
+  let g:ale_set_quickfix = 0
+  let g:ale_open_list = 1
+  let g:ale_keep_list_window_open = 0
+  " With empty loclist, window must stay close
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  " With a loclist it must open
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  " And with keep open option, must stay open even with empty loclist
+  let g:ale_keep_list_window_open = 1
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+
+Execute (loclist without openlist):
+  let g:ale_set_loclist = 1
+  let g:ale_set_quickfix = 0
+  let g:ale_open_list = 0
+  " Must stay close without loclist
+  let g:ale_keep_list_window_open = 0
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  " Must stay open event without loclist
+  let g:ale_keep_list_window_open = 1
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+
+Execute (quickfix and openlist):
+  let g:ale_set_loclist = 0
+  let g:ale_set_quickfix = 1
+  let g:ale_open_list = 1
+  let g:ale_keep_list_window_open = 0
+  " With empty loclist, window must stay close
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  " With a loclist it must open
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  " And with keep open option, must stay open even with empty loclist
+  let g:ale_keep_list_window_open = 1
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+
+Execute (quickfix without openlist):
+  let g:ale_set_loclist = 0
+  let g:ale_set_quickfix = 1
+  let g:ale_open_list = 0
+  " Must stay close without loclist
+  let g:ale_keep_list_window_open = 0
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 0, ale#list#IsQuickfixOpen()
+  " Must stay open event without loclist
+  let g:ale_keep_list_window_open = 1
+  call ale#list#SetLists(g:empty_loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()
+  call ale#list#SetLists(g:loclist)
+  AssertEqual 1, ale#list#IsQuickfixOpen()