Merge pull request #14115 from mfussenegger/lsp-commands

lsp: Add a registry for client side code action commands

4 files changed, 100 insertions, 14 deletions

diff --git a/runtime/doc/lsp.txt b/runtime/doc/lsp.txt
index 48d65a22b6..c434f6db66 100644
--- a/runtime/doc/lsp.txt
+++ b/runtime/doc/lsp.txt
@@ -224,6 +224,11 @@ For |lsp-request|, each |lsp-handler| has this signature: >
                                             The ID of the |vim.lsp.client|.
                             {bufnr}     (Buffer)
                                            Buffer handle, or 0 for current.
+
+                            {params}    (table|nil)
+                                           The parameters used in the original request
+                                           which resulted in this handler
+                                           call.
             {config}    (table)
                             Configuration for the handler.
 
@@ -234,6 +239,7 @@ For |lsp-request|, each |lsp-handler| has this signature: >
                             To configure a particular |lsp-handler|, see:
                                 |lsp-handler-configuration|
 
+
         Returns: ~
             The |lsp-handler| can respond by returning two values: `result, err`
               Where `err` must be shaped like an RPC error:
diff --git a/runtime/lua/vim/lsp.lua b/runtime/lua/vim/lsp.lua
index 90c5872f11..ae9a7ab513 100644
--- a/runtime/lua/vim/lsp.lua
+++ b/runtime/lua/vim/lsp.lua
@@ -896,7 +896,7 @@ function lsp.start_client(config)
 
     local _ = log.debug() and log.debug(log_prefix, "client.request", client_id, method, params, handler, bufnr)
     return rpc.request(method, params, function(err, result)
-      handler(err, result, {method=method, client_id=client_id, bufnr=bufnr})
+      handler(err, result, {method=method, client_id=client_id, bufnr=bufnr, params=params})
     end)
   end
 
@@ -1534,5 +1534,34 @@ function lsp._with_extend(name, options, user_config)
   return resulting_config
 end
 
+
+--- Registry for client side commands.
+--- This is an extension point for plugins to handle custom commands which are
+--- not part of the core language server protocol specification.
+---
+--- The registry is a table where the key is a unique command name,
+--- and the value is a function which is called if any LSP action
+--- (code action, code lenses, ...) triggers the command.
+---
+--- If a LSP response contains a command for which no matching entry is
+--- available in this registry, the command will be executed via the LSP server
+--- using `workspace/executeCommand`.
+---
+--- The first argument to the function will be the `Command`:
+--    Command
+--      title: String
+--      command: String
+--      arguments?: any[]
+--
+--- The second argument is the `ctx` of |lsp-handler|
+lsp.commands = setmetatable({}, {
+  __newindex = function(tbl, key, value)
+    assert(type(key) == 'string', "The key for commands in `vim.lsp.commands` must be a string")
+    assert(type(value) == 'function', "Command added to `vim.lsp.commands` must be a function")
+    rawset(tbl, key, value)
+  end;
+})
+
+
 return lsp
 -- vim:sw=2 ts=2 et
diff --git a/runtime/lua/vim/lsp/handlers.lua b/runtime/lua/vim/lsp/handlers.lua
index 918666ab27..c2f2b870f7 100644
--- a/runtime/lua/vim/lsp/handlers.lua
+++ b/runtime/lua/vim/lsp/handlers.lua
@@ -110,7 +110,7 @@ M['client/registerCapability'] = function(_, _, ctx)
 end
 
 --see: https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_codeAction
-M['textDocument/codeAction'] = function(_, result)
+M['textDocument/codeAction'] = function(_, result, ctx)
   if result == nil or vim.tbl_isempty(result) then
     print("No code actions available")
     return
@@ -127,19 +127,28 @@ M['textDocument/codeAction'] = function(_, result)
   if choice < 1 or choice > #result then
     return
   end
-  local action_chosen = result[choice]
-  -- textDocument/codeAction can return either Command[] or CodeAction[].
-  -- If it is a CodeAction, it can have either an edit, a command or both.
-  -- Edits should be executed first
-  if action_chosen.edit or type(action_chosen.command) == "table" then
-    if action_chosen.edit then
-      util.apply_workspace_edit(action_chosen.edit)
-    end
-    if type(action_chosen.command) == "table" then
-      buf.execute_command(action_chosen.command)
-    end
+  local action = result[choice]
+  -- textDocument/codeAction can return either Command[] or CodeAction[]
+  --
+  -- CodeAction
+  --  ...
+  --  edit?: WorkspaceEdit    -- <- must be applied before command
+  --  command?: Command
+  --
+  -- Command:
+  --  title: string
+  --  command: string
+  --  arguments?: any[]
+  --
+  if action.edit then
+    util.apply_workspace_edit(action.edit)
+  end
+  local command = type(action.command) == 'table' and action.command or action
+  local fn = vim.lsp.commands[command.command]
+  if fn then
+    fn(command, ctx)
   else
-    buf.execute_command(action_chosen)
+    buf.execute_command(command)
   end
 end
 
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 6ad37110c7..27f2d2536f 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -2353,6 +2353,10 @@ describe('LSP', function()
           eq(0, signal, "exit signal", fake_lsp_logfile)
         end;
         on_handler = function(err, result, ctx)
+          -- Don't compare & assert params, they're not relevant for the testcase
+          -- This allows us to be lazy and avoid declaring them
+          ctx.params = nil
+
           eq(table.remove(test.expected_handlers), {err, result, ctx}, "expected handler")
           if ctx.method == 'start' then
             exec_lua("vim.lsp.buf.rename()")
@@ -2370,4 +2374,42 @@ describe('LSP', function()
     end
   end)
 
+  describe('vim.lsp.buf.code_action', function()
+    it('Calls client side command if available', function()
+      eq(1, exec_lua [[
+        local dummy_calls = 0
+        vim.lsp.commands.dummy = function()
+          dummy_calls = dummy_calls + 1
+        end
+        local actions = {
+          {
+            title = 'Dummy command',
+            command = 'dummy',
+          },
+        }
+        -- inputlist would require input and block the test;
+        vim.fn.inputlist = function()
+          return 1
+        end
+        local params = {}
+        local handler = require'vim.lsp.handlers'['textDocument/codeAction']
+        handler(nil, actions, { method = 'textDocument/codeAction', params = params }, nil)
+        return dummy_calls
+      ]])
+    end)
+  end)
+  describe('vim.lsp.commands', function()
+    it('Accepts only string keys', function()
+      matches(
+        '.*The key for commands in `vim.lsp.commands` must be a string',
+        pcall_err(exec_lua, 'vim.lsp.commands[1] = function() end')
+      )
+    end)
+    it('Accepts only function values', function()
+      matches(
+        '.*Command added to `vim.lsp.commands` must be a function',
+        pcall_err(exec_lua, 'vim.lsp.commands.dummy = 10')
+      )
+    end)
+  end)
 end)