fix(secure): crash when hitting escape in prompt (#21283)

- use pcall when calling vim.secure.read from C
- catch keyboard interrupts in vim.secure.read, rethrow other errors
- selecting "view" in prompt runs :view command
- simplify lua stack cleanup with lua_gettop and lua_settop

Co-authored-by: ii14 <ii14@users.noreply.github.com>

runtime/lua/vim/secure.lua

@@ -80,34 +80,27 @@ function M.read(path)
   end
 
   -- File either does not exist in trust database or the hash does not match
-  local choice = vim.fn.confirm(
+  local ok, result = pcall(
+    vim.fn.confirm,
     string.format('%s is not trusted.', fullpath),
     '&ignore\n&view\n&deny\n&allow',
     1
   )
 
-  if choice == 0 or choice == 1 then
+  if not ok and result ~= 'Keyboard interrupt' then
+    error(result)
+  elseif not ok or result == 0 or result == 1 then
     -- Cancelled or ignored
     return nil
-  elseif choice == 2 then
+  elseif result == 2 then
     -- View
-    vim.cmd('new')
-    local buf = vim.api.nvim_get_current_buf()
-    local lines = vim.split(string.gsub(contents, '\n$', ''), '\n')
-    vim.api.nvim_buf_set_lines(buf, 0, -1, false, lines)
-    vim.bo[buf].bufhidden = 'hide'
-    vim.bo[buf].buftype = 'nofile'
-    vim.bo[buf].swapfile = false
-    vim.bo[buf].modeline = false
-    vim.bo[buf].buflisted = false
-    vim.bo[buf].readonly = true
-    vim.bo[buf].modifiable = false
+    vim.cmd('sview ' .. fullpath)
     return nil
-  elseif choice == 3 then
+  elseif result == 3 then
     -- Deny
     trust[fullpath] = '!'
     contents = nil
-  elseif choice == 4 then
+  elseif result == 4 then
     -- Allow
     trust[fullpath] = hash
   end

src/nvim/lua/executor.c

@@ -2197,11 +2197,17 @@ plain:
 char *nlua_read_secure(const char *path)
 {
   lua_State *const lstate = global_lstate;
+  const int top = lua_gettop(lstate);
+
   lua_getglobal(lstate, "vim");
   lua_getfield(lstate, -1, "secure");
   lua_getfield(lstate, -1, "read");
   lua_pushstring(lstate, path);
-  lua_call(lstate, 1, 1);
+  if (nlua_pcall(lstate, 1, 1)) {
+    nlua_error(lstate, _("Error executing vim.secure.read: %.*s"));
+    lua_settop(lstate, top);
+    return NULL;
+  }
 
   size_t len = 0;
   const char *contents = lua_tolstring(lstate, -1, &len);
@@ -2212,15 +2218,15 @@ char *nlua_read_secure(const char *path)
     memcpy(buf, contents, len + 1);
   }
 
-  // Pop return value, "vim", and "secure"
-  lua_pop(lstate, 3);
-
+  lua_settop(lstate, top);
   return buf;
 }
 
 bool nlua_trust(const char *action, const char *path)
 {
   lua_State *const lstate = global_lstate;
+  const int top = lua_gettop(lstate);
+
   lua_getglobal(lstate, "vim");
   lua_getfield(lstate, -1, "secure");
   lua_getfield(lstate, -1, "trust");
@@ -2241,6 +2247,7 @@ bool nlua_trust(const char *action, const char *path)
 
   if (nlua_pcall(lstate, 1, 2)) {
     nlua_error(lstate, _("Error executing vim.secure.trust: %.*s"));
+    lua_settop(lstate, top);
     return false;
   }
 
@@ -2260,8 +2267,6 @@ bool nlua_trust(const char *action, const char *path)
     }
   }
 
-  // Pop return values, "vim" and "secure"
-  lua_pop(lstate, 4);
-
+  lua_settop(lstate, top);
   return success;
 }

test/functional/lua/secure_spec.lua

@@ -150,10 +150,10 @@ describe('vim.secure', function()
       ]]}
       feed('v')
       screen:expect{grid=[[
-        ^  let g:foobar = 42                                                             |
+          ^let g:foobar = 42                                                             |
         {1:~                                                                               }|
         {1:~                                                                               }|
-        {2:]] .. cwd .. pathsep .. [[Xfile [RO]{MATCH:%s+}|
+        {2:]] .. funcs.fnamemodify(cwd, ':~') .. pathsep .. [[Xfile [RO]{MATCH:%s+}|
                                                                                         |
         {1:~                                                                               }|
         {4:[No Name]                                                                       }|
@@ -166,7 +166,7 @@ describe('vim.secure', function()
 
       -- Cannot write file
       pcall_err(command, 'write')
-      eq(false, curbufmeths.get_option('modifiable'))
+      eq(true, curbufmeths.get_option('readonly'))
     end)
   end)