fix(lsp): retrigger diagnostics request on server cancellation (#31345)

Co-authored-by: Jesse <github@jessebakker.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/test/functional/plugin/lsp/diagnostic_spec.lua b/test/functional/plugin/lsp/diagnostic_spec.lua
index 5afbe22793..ca9196562c 100644
--- a/test/functional/plugin/lsp/diagnostic_spec.lua
+++ b/test/functional/plugin/lsp/diagnostic_spec.lua
@@ -209,10 +209,16 @@ describe('vim.lsp.diagnostic', function()
     before_each(function()
       exec_lua(create_server_definition)
       exec_lua(function()
+        _G.requests = 0
         _G.server = _G._create_server({
           capabilities = {
             diagnosticProvider = {},
           },
+          handlers = {
+            [vim.lsp.protocol.Methods.textDocument_diagnostic] = function()
+              _G.requests = _G.requests + 1
+            end,
+          },
         })
 
         function _G.get_extmarks(bufnr, client_id0)
@@ -373,5 +379,56 @@ describe('vim.lsp.diagnostic', function()
         end)
       )
     end)
+
+    it('handles server cancellation', function()
+      eq(
+        1,
+        exec_lua(function()
+          vim.lsp.diagnostic.on_diagnostic({
+            code = vim.lsp.protocol.ErrorCodes.ServerCancelled,
+            -- Empty data defaults to retriggering request
+            data = {},
+            message = '',
+          }, {}, {
+            method = vim.lsp.protocol.Methods.textDocument_diagnostic,
+            client_id = client_id,
+          })
+
+          return _G.requests
+        end)
+      )
+
+      eq(
+        2,
+        exec_lua(function()
+          vim.lsp.diagnostic.on_diagnostic({
+            code = vim.lsp.protocol.ErrorCodes.ServerCancelled,
+            data = { retriggerRequest = true },
+            message = '',
+          }, {}, {
+            method = vim.lsp.protocol.Methods.textDocument_diagnostic,
+            client_id = client_id,
+          })
+
+          return _G.requests
+        end)
+      )
+
+      eq(
+        2,
+        exec_lua(function()
+          vim.lsp.diagnostic.on_diagnostic({
+            code = vim.lsp.protocol.ErrorCodes.ServerCancelled,
+            data = { retriggerRequest = false },
+            message = '',
+          }, {}, {
+            method = vim.lsp.protocol.Methods.textDocument_diagnostic,
+            client_id = client_id,
+          })
+
+          return _G.requests
+        end)
+      )
+    end)
   end)
 end)