Avoid using the `condition and expr1 or expr2` pattern when `expr1` can be `nil` or `false`, as this will always return `expr2` regardless of the condition result. This is a common source of subtle bugs in Lua code. The pattern `condition and expr1 or expr2` only works correctly when `expr1` is guaranteed to be truthy. When `expr1` can be `nil` or `false`, the `or expr2` part will always execute, making the condition meaningless. **Problematic examples:** ```lua -- This will always return `enable`, never `nil` vim.b[bufnr][var] = enable == vim.g[var] and nil or enable -- This fails when enable is false bufstate.enabled = enable ~= globalstate.enabled and enable or nil ``` **Safe alternatives:** ```lua -- Use explicit if-else if enable == vim.g[var] then vim.b[bufnr][var] = nil else vim.b[bufnr][var] = enable end -- Use vim.F.if_nil for nil-specific cases result = vim.F.if_nil(potentially_nil_value, fallback) ``` This pattern is particularly dangerous because it appears to work correctly in many cases, making the bug difficult to detect during testing.