Fix #907 - Stop LSP integration breaking with empty string keys in NeoVim

autoload/ale/lsp.vim

@@ -242,10 +242,14 @@ function! s:HandleCommandMessage(job_id, message) abort
     call ale#lsp#HandleMessage(l:conn, a:message)
 endfunction
 
-function! s:RegisterProject(conn, project_root) abort
+function! ale#lsp#RegisterProject(conn, project_root) abort
-    if !has_key(a:conn.projects, a:project_root)
+    " Empty strings can't be used for Dictionary keys in NeoVim, due to E713.
+    " This appears to be a nonsensical bug in NeoVim.
+    let l:key = empty(a:project_root) ? '<<EMPTY>>' : a:project_root
+
+    if !has_key(a:conn.projects, l:key)
         " Tools without project roots are ready right away, like tsserver.
-        let a:conn.projects[a:project_root] = {
+        let a:conn.projects[l:key] = {
         \   'initialized': empty(a:project_root),
         \   'init_request_id': 0,
         \   'message_queue': [],
@@ -253,6 +257,12 @@ function! s:RegisterProject(conn, project_root) abort
     endif
 endfunction
 
+function! ale#lsp#GetProject(conn, project_root) abort
+    let l:key = empty(a:project_root) ? '<<EMPTY>>' : a:project_root
+
+    return get(a:conn.projects, l:key, {})
+endfunction
+
 " Start a program for LSP servers which run with executables.
 "
 " The job ID will be returned for for the program if it ran, otherwise
@@ -285,7 +295,7 @@ function! ale#lsp#StartProgram(executable, command, project_root, callback) abor
     let l:conn.id = l:job_id
     " Add the callback to the List if it's not there already.
     call uniq(sort(add(l:conn.callback_list, a:callback)))
-    call s:RegisterProject(l:conn, a:project_root)
+    call ale#lsp#RegisterProject(l:conn, a:project_root)
 
     return l:job_id
 endfunction
@@ -311,7 +321,7 @@ function! ale#lsp#ConnectToAddress(address, project_root, callback) abort
     let l:conn.id = a:address
     " Add the callback to the List if it's not there already.
     call uniq(sort(add(l:conn.callback_list, a:callback)))
-    call s:RegisterProject(l:conn, a:project_root)
+    call ale#lsp#RegisterProject(l:conn, a:project_root)
 
     return 1
 endfunction
@@ -344,7 +354,7 @@ function! ale#lsp#Send(conn_id, message, ...) abort
         return 0
     endif
 
-    let l:project = get(l:conn.projects, l:project_root, {})
+    let l:project = ale#lsp#GetProject(l:conn, l:project_root)
 
     if empty(l:project)
         return 0

test/lsp/test_lsp_connections.vader

@@ -3,6 +3,7 @@ Before:
 
 After:
   unlet! b:data
+  unlet! b:conn
 
 Execute(GetNextMessageID() should increment appropriately):
   " We should get the initial ID, and increment a bit.
@@ -220,3 +221,51 @@ Execute(ale#lsp#ReadMessageData() should handle a message with part of a second
   \   . '{"id":2,"jsonrpc":"2.0","result":{"foo":"barÜ"}}'
   \   . b:data
   \ )
+
+Execute(Projects with regular project roots should be registered correctly):
+  let b:conn = {'projects': {}}
+
+  call ale#lsp#RegisterProject(b:conn, '/foo/bar')
+
+  AssertEqual
+  \ {
+  \   'projects': {
+  \     '/foo/bar': {'initialized': 0, 'message_queue': [], 'init_request_id': 0},
+  \   },
+  \ },
+  \ b:conn
+
+Execute(Projects with regular project roots should be fetched correctly):
+  let b:conn = {
+  \ 'projects': {
+  \   '/foo/bar': {'initialized': 0, 'message_queue': [], 'init_request_id': 0},
+  \ },
+  \}
+
+  AssertEqual
+  \ {'initialized': 0, 'message_queue': [], 'init_request_id': 0},
+  \ ale#lsp#GetProject(b:conn, '/foo/bar')
+
+Execute(Projects with empty project roots should be registered correctly):
+  let b:conn = {'projects': {}}
+
+  call ale#lsp#RegisterProject(b:conn, '')
+
+  AssertEqual
+  \ {
+  \   'projects': {
+  \     '<<EMPTY>>': {'initialized': 1, 'message_queue': [], 'init_request_id': 0},
+  \   },
+  \ },
+  \ b:conn
+
+Execute(Projects with empty project roots should be fetched correctly):
+  let b:conn = {
+  \ 'projects': {
+  \   '<<EMPTY>>': {'initialized': 1, 'message_queue': [], 'init_request_id': 0},
+  \ },
+  \}
+
+  AssertEqual
+  \ {'initialized': 1, 'message_queue': [], 'init_request_id': 0},
+  \ ale#lsp#GetProject(b:conn, '')