fix(:restart): avoid ERR/WRN logging on Windows with --listen (#39287)

Problem:  :restart leads to ERR/WRN logging on Windows with --listen.
Solution: Add a log_level flag to vim._with() and use it to suppress
          logging from serverstart()/serverstop() during restart.
(cherry picked from commit 208951cbc0)

runtime/lua/vim/_core/server.lua

@@ -54,6 +54,9 @@ function M.rebind_old_addr_after_restart(canonical_addr, bootstrap_addr, expecte
   local poll_elapsed = 0
   timer:start(poll_ms, poll_ms, function()
     vim.schedule(function()
+      if timer:is_closing() then
+        return
+      end
       poll_elapsed = poll_elapsed + poll_ms
       if poll_elapsed >= max_wait_ms then
         timer:stop()
@@ -61,7 +64,9 @@ function M.rebind_old_addr_after_restart(canonical_addr, bootstrap_addr, expecte
         return
       end
       if not vim.list_contains(vim.fn.serverlist(), canonical_addr) then
-        local ok = pcall(vim.fn.serverstart, canonical_addr)
+        local ok = vim._with({ log_level = 5 }, function()
+          return pcall(vim.fn.serverstart, canonical_addr)
+        end)
         if not ok then
           return -- pipe still held by old server; retry next tick
         end
@@ -72,11 +77,16 @@ function M.rebind_old_addr_after_restart(canonical_addr, bootstrap_addr, expecte
       timer:stop()
       timer:start(poll_ms, poll_ms, function()
         vim.schedule(function()
+          if timer:is_closing() then
+            return
+          end
           elapsed = elapsed + poll_ms
           local all_uis = expected_uis <= 0 or #vim.api.nvim_list_uis() >= expected_uis
           if all_uis or elapsed >= max_wait_ms then
             if canonical_addr ~= bootstrap_addr then
-              pcall(vim.fn.serverstop, bootstrap_addr)
+              vim._with({ log_level = 5 }, function()
+                pcall(vim.fn.serverstop, bootstrap_addr)
+              end)
             end
             timer:stop()
             timer:close()

src/nvim/log.c

@@ -149,13 +149,9 @@ bool logmsg(int log_level, const char *context, const char *func_name, int line_
     return false;
   }
 
-#ifndef NVIM_LOG_DEBUG
-  // This should rarely happen (callsites are compiled out), but to be sure.
-  // TODO(bfredl): allow log levels to be configured at runtime
-  if (log_level < LOGLVL_WRN) {
+  if (log_level < g_min_log_level) {
     return false;
   }
-#endif
 
 #ifdef EXITFREE
   // Logging after we've already started freeing all our memory will only cause

src/nvim/log.h

@@ -51,4 +51,10 @@
 # define LOG_CALLSTACK_TO_FILE(fp) log_callstack_to_file(fp, __func__, __LINE__)
 #endif
 
+#ifndef NVIM_LOG_DEBUG
+EXTERN int g_min_log_level INIT( = LOGLVL_WRN);
+#else
+EXTERN int g_min_log_level INIT( = 0);
+#endif
+
 #include "log.h.generated.h"

src/nvim/lua/stdlib.c

@@ -8,6 +8,7 @@
 #include <string.h>
 #include <uv.h>
 
+#include "nvim/log.h"
 #ifdef NVIM_VENDOR_BIT
 # include "bit.h"
 #endif
@@ -581,6 +582,7 @@ static int nlua_with(lua_State *L)
   int flags = 0;
   buf_T *buf = NULL;
   win_T *win = NULL;
+  int log_level = -1;
 
 #define APPLY_FLAG(key, flag) \
   if (strequal((key), k) && (v)) { \
@@ -594,10 +596,12 @@ static int nlua_with(lua_State *L)
     if (lua_type(L, -2) == LUA_TSTRING) {
       const char *k = lua_tostring(L, -2);
       bool v = lua_toboolean(L, -1);
-      if (strequal("buf", k)) { \
+      if (strequal("buf", k)) {
         buf = handle_get_buffer((int)luaL_checkinteger(L, -1));
-      } else if (strequal("win", k)) { \
+      } else if (strequal("win", k)) {
         win = handle_get_window((int)luaL_checkinteger(L, -1));
+      } else if (strequal("log_level", k)) {
+        log_level = (int)luaL_checkinteger(L, -1);
       } else {
         APPLY_FLAG("sandbox", CMOD_SANDBOX);
         APPLY_FLAG("silent", CMOD_SILENT);
@@ -618,6 +622,10 @@ static int nlua_with(lua_State *L)
   int status = 0;
   int rets = 0;
 
+  const int save_min_log_level = g_min_log_level;
+  if (log_level >= 0) {
+    g_min_log_level = log_level;
+  }
   cmdmod_T save_cmdmod = cmdmod;
   CLEAR_FIELD(cmdmod);
   cmdmod.cmod_flags = flags;
@@ -652,6 +660,9 @@ static int nlua_with(lua_State *L)
 
   undo_cmdmod(&cmdmod);
   cmdmod = save_cmdmod;
+  if (log_level >= 0) {
+    g_min_log_level = save_min_log_level;
+  }
 
   if (status) {
     return lua_error(L);