fix(lsp): handle textDocumentSync.save bool capability (#18332)

Follow up to https://github.com/neovim/neovim/pull/17814

runtime/lua/vim/lsp.lua

@@ -1208,10 +1208,11 @@ function lsp._text_document_did_save_handler(bufnr)
   bufnr = resolve_bufnr(bufnr)
   local uri = vim.uri_from_bufnr(bufnr)
   local text = once(buf_get_full_text)
-  for_each_buffer_client(bufnr, function(client, _client_id)
+  for_each_buffer_client(bufnr, function(client)
-    if vim.tbl_get(client.server_capabilities, "textDocumentSync", "save") then
+    local save_capability = vim.tbl_get(client.server_capabilities, "textDocumentSync", "save")
+    if save_capability then
       local included_text
-      if vim.tbl_get(client.server_capabilities, "textDocumentSync", "save", "includeText") then
+      if type(save_capability) == "table" and save_capability.includeText then
         included_text = text(bufnr)
       end
       client.notify('textDocument/didSave', {

test/functional/fixtures/fake-lsp-server.lua

@@ -28,7 +28,10 @@ local function assert_eq(a, b, ...)
   if not vim.deep_equal(a, b) then
     error(message_parts(": ",
       ..., "assert_eq failed",
-      string.format("left == %q, right == %q", vim.inspect(a), vim.inspect(b))
+      string.format("left == %q, right == %q",
+        table.concat(vim.split(vim.inspect(a), "\n"), ""),
+        table.concat(vim.split(vim.inspect(b), "\n"), "")
+      )
     ))
   end
 end
@@ -245,6 +248,51 @@ function tests.basic_check_capabilities()
   }
 end
 
+function tests.text_document_sync_save_bool()
+  skeleton {
+    on_init = function()
+      return {
+        capabilities = {
+          textDocumentSync = {
+            save = true
+          }
+        }
+      }
+    end;
+    body = function()
+      notify('start')
+      expect_notification('textDocument/didSave', {textDocument = { uri = "file://" }})
+      notify('shutdown')
+    end;
+  }
+end
+
+function tests.text_document_sync_save_includeText()
+  skeleton {
+    on_init = function()
+      return {
+        capabilities = {
+          textDocumentSync = {
+            save = {
+              includeText = true
+            }
+          }
+        }
+      }
+    end;
+    body = function()
+      notify('start')
+      expect_notification('textDocument/didSave', {
+        textDocument = {
+          uri = "file://"
+        },
+        text = "help me\n"
+      })
+      notify('shutdown')
+    end;
+  }
+end
+
 function tests.capabilities_for_client_supports_method()
   skeleton {
     on_init = function(params)

test/functional/plugin/lsp_spec.lua

@@ -421,6 +421,67 @@ describe('LSP', function()
       }
     end)
 
+    it('_text_document_did_save_handler sends didSave with bool textDocumentSync.save', function()
+      local expected_handlers = {
+        {NIL, {}, {method="shutdown", client_id=1}};
+        {NIL, {}, {method="start", client_id=1}};
+      }
+      local client
+      test_rpc_server {
+        test_name = "text_document_sync_save_bool";
+        on_init = function(c)
+          client = c
+        end;
+        on_exit = function(code, signal)
+          eq(0, code, "exit code", fake_lsp_logfile)
+          eq(0, signal, "exit signal", fake_lsp_logfile)
+        end;
+        on_handler = function(err, result, ctx)
+          eq(table.remove(expected_handlers), {err, result, ctx}, "expected handler")
+          if ctx.method == "start" then
+            exec_lua([=[
+              BUFFER = vim.api.nvim_get_current_buf()
+              lsp.buf_attach_client(BUFFER, TEST_RPC_CLIENT_ID)
+              lsp._text_document_did_save_handler(BUFFER)
+            ]=])
+          else
+            client.stop()
+          end
+        end;
+      }
+    end)
+
+    it('_text_document_did_save_handler sends didSave including text if server capability is set', function()
+      local expected_handlers = {
+        {NIL, {}, {method="shutdown", client_id=1}};
+        {NIL, {}, {method="start", client_id=1}};
+      }
+      local client
+      test_rpc_server {
+        test_name = "text_document_sync_save_includeText";
+        on_init = function(c)
+          client = c
+        end;
+        on_exit = function(code, signal)
+          eq(0, code, "exit code", fake_lsp_logfile)
+          eq(0, signal, "exit signal", fake_lsp_logfile)
+        end;
+        on_handler = function(err, result, ctx)
+          eq(table.remove(expected_handlers), {err, result, ctx}, "expected handler")
+          if ctx.method == "start" then
+            exec_lua([=[
+              BUFFER = vim.api.nvim_get_current_buf()
+              vim.api.nvim_buf_set_lines(BUFFER, 0, -1, true, {"help me"})
+              lsp.buf_attach_client(BUFFER, TEST_RPC_CLIENT_ID)
+              lsp._text_document_did_save_handler(BUFFER)
+            ]=])
+          else
+            client.stop()
+          end
+        end;
+      }
+    end)
+
     it('client.supports_methods() should validate capabilities', function()
       local expected_handlers = {
         {NIL, {}, {method="shutdown", client_id=1}};