feat(diagnostic): vim.diagnostic.is_disabled() #21527

4 files changed, 63 insertions, 14 deletions

diff --git a/runtime/doc/diagnostic.txt b/runtime/doc/diagnostic.txt
index 66ac2170e3..7066a3739a 100644
--- a/runtime/doc/diagnostic.txt
+++ b/runtime/doc/diagnostic.txt
@@ -565,6 +565,18 @@ hide({namespace}, {bufnr})                             *vim.diagnostic.hide()*
       • {bufnr}      (number|nil) Buffer number, or 0 for current buffer. When
                      omitted, hide diagnostics in all buffers.
 
+is_disabled({bufnr}, {namespace})               *vim.diagnostic.is_disabled()*
+    Check whether diagnostics are disabled in a given buffer.
+
+    Parameters: ~
+      • {bufnr}      (number|nil) Buffer number, or 0 for current buffer.
+      • {namespace}  (number|nil) Diagnostic namespace. When omitted, checks if all diagnostics are
+                     disabled in {bufnr}. Otherwise, only checks if
+                     diagnostics from {namespace} are disabled.
+
+    Return: ~
+        (boolean)
+
                                                       *vim.diagnostic.match()*
 match({str}, {pat}, {groups}, {severity_map}, {defaults})
     Parse a diagnostic from a string.
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index 7dceaa3318..ce07c3035c 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -135,6 +135,9 @@ The following new APIs or features were added.
 
   See https://github.com/neovim/neovim/pull/14537.
 
+• |vim.diagnostic.is_disabled()| checks if diagnostics are disabled in a given
+  buffer or namespace.
+
 • |--remote-ui| option was added to connect to a remote instance and display
   in it in a |TUI| in the local terminal. This can be used run a headless nvim
   instance in the background and display its UI on demand, which previously
diff --git a/runtime/lua/vim/diagnostic.lua b/runtime/lua/vim/diagnostic.lua
index f41f4a9c68..6fd000a029 100644
--- a/runtime/lua/vim/diagnostic.lua
+++ b/runtime/lua/vim/diagnostic.lua
@@ -252,19 +252,6 @@ local function get_bufnr(bufnr)
 end
 
 ---@private
-local function is_disabled(namespace, bufnr)
-  local ns = M.get_namespace(namespace)
-  if ns.disabled then
-    return true
-  end
-
-  if type(diagnostic_disabled[bufnr]) == 'table' then
-    return diagnostic_disabled[bufnr][namespace]
-  end
-  return diagnostic_disabled[bufnr]
-end
-
----@private
 local function diagnostic_lines(diagnostics)
   if not diagnostics then
     return {}
@@ -1119,6 +1106,27 @@ function M.hide(namespace, bufnr)
   end
 end
 
+--- Check whether diagnostics are disabled in a given buffer.
+---
+---@param bufnr number|nil Buffer number, or 0 for current buffer.
+---@param namespace number|nil Diagnostic namespace. When omitted, checks if
+---                            all diagnostics are disabled in {bufnr}.
+---                            Otherwise, only checks if diagnostics from
+---                            {namespace} are disabled.
+---@return boolean
+function M.is_disabled(bufnr, namespace)
+  bufnr = get_bufnr(bufnr)
+  if namespace and M.get_namespace(namespace).disabled then
+    return true
+  end
+
+  if type(diagnostic_disabled[bufnr]) == 'table' then
+    return diagnostic_disabled[bufnr][namespace]
+  end
+
+  return diagnostic_disabled[bufnr] ~= nil
+end
+
 --- Display diagnostics for the given namespace and buffer.
 ---
 ---@param namespace number|nil Diagnostic namespace. When omitted, show
@@ -1162,7 +1170,7 @@ function M.show(namespace, bufnr, diagnostics, opts)
     return
   end
 
-  if is_disabled(namespace, bufnr) then
+  if M.is_disabled(bufnr, namespace) then
     return
   end
 
diff --git a/test/functional/lua/diagnostic_spec.lua b/test/functional/lua/diagnostic_spec.lua
index 946994fd97..d364986ad7 100644
--- a/test/functional/lua/diagnostic_spec.lua
+++ b/test/functional/lua/diagnostic_spec.lua
@@ -2124,5 +2124,31 @@ end)
         return vim.g.diagnostic_autocmd_triggered == diagnostic_bufnr
       ]])
       end)
+
+    it("checks if diagnostics are disabled in a buffer", function()
+      eq({true, true, true , true}, exec_lua [[
+        vim.diagnostic.set(diagnostic_ns, diagnostic_bufnr, {
+          make_error('Diagnostic #1', 1, 1, 1, 1),
+        })
+        vim.api.nvim_set_current_buf(diagnostic_bufnr)
+        vim.diagnostic.disable()
+        return {
+          vim.diagnostic.is_disabled(),
+          vim.diagnostic.is_disabled(diagnostic_bufnr),
+          vim.diagnostic.is_disabled(diagnostic_bufnr, diagnostic_ns),
+          vim.diagnostic.is_disabled(_, diagnostic_ns),
+        }
+      ]])
+
+      eq({false, false, false , false}, exec_lua [[
+        vim.diagnostic.enable()
+        return {
+          vim.diagnostic.is_disabled(),
+          vim.diagnostic.is_disabled(diagnostic_bufnr),
+          vim.diagnostic.is_disabled(diagnostic_bufnr, diagnostic_ns),
+          vim.diagnostic.is_disabled(_, diagnostic_ns),
+        }
+      ]])
+    end)
   end)
 end)