clippy_lints/src/dbg_macro.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::macros::root_macro_call_first_node;
   3 use clippy_utils::source::snippet_with_applicability;
   4 use clippy_utils::{is_in_cfg_test, is_in_test_function};
   5 use rustc_errors::Applicability;
   6 use rustc_hir::{Expr, ExprKind};
   7 use rustc_lint::{LateContext, LateLintPass};
   8 use rustc_session::{declare_tool_lint, impl_lint_pass};
   9 use rustc_span::sym;
  10
  11 declare_clippy_lint! {
  12     /// ### What it does
  13     /// Checks for usage of dbg!() macro.
  14     ///
  15     /// ### Why is this bad?
  16     /// `dbg!` macro is intended as a debugging tool. It
  17     /// should not be in version control.
  18     ///
  19     /// ### Example
  20     /// ```rust,ignore
  21     /// dbg!(true)
  22     /// ```
  23     ///
  24     /// Use instead:
  25     /// ```rust,ignore
  26     /// true
  27     /// ```
  28     #[clippy::version = "1.34.0"]
  29     pub DBG_MACRO,
  30     restriction,
  31     "`dbg!` macro is intended as a debugging tool"
  32 }
  33
  34 #[derive(Copy, Clone)]
  35 pub struct DbgMacro {
  36     allow_dbg_in_tests: bool,
  37 }
  38
  39 impl_lint_pass!(DbgMacro => [DBG_MACRO]);
  40
  41 impl DbgMacro {
  42     pub fn new(allow_dbg_in_tests: bool) -> Self {
  43         DbgMacro { allow_dbg_in_tests }
  44     }
  45 }
  46
  47 impl LateLintPass<'_> for DbgMacro {
  48     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
  49         let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return };
  50         if cx.tcx.is_diagnostic_item(sym::dbg_macro, macro_call.def_id) {
  51             // allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
  52             if self.allow_dbg_in_tests
  53                 && (is_in_test_function(cx.tcx, expr.hir_id) || is_in_cfg_test(cx.tcx, expr.hir_id))
  54             {
  55                 return;
  56             }
  57             let mut applicability = Applicability::MachineApplicable;
  58             let suggestion = match expr.peel_drop_temps().kind {
  59                 // dbg!()
  60                 ExprKind::Block(_, _) => String::new(),
  61                 // dbg!(1)
  62                 ExprKind::Match(val, ..) => {
  63                     snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability).to_string()
  64                 },
  65                 // dbg!(2, 3)
  66                 ExprKind::Tup(
  67                     [
  68                         Expr {
  69                             kind: ExprKind::Match(first, ..),
  70                             ..
  71                         },
  72                         ..,
  73                         Expr {
  74                             kind: ExprKind::Match(last, ..),
  75                             ..
  76                         },
  77                     ],
  78                 ) => {
  79                     let snippet = snippet_with_applicability(
  80                         cx,
  81                         first.span.source_callsite().to(last.span.source_callsite()),
  82                         "..",
  83                         &mut applicability,
  84                     );
  85                     format!("({snippet})")
  86                 },
  87                 _ => return,
  88             };
  89
  90             span_lint_and_sugg(
  91                 cx,
  92                 DBG_MACRO,
  93                 macro_call.span,
  94                 "`dbg!` macro is intended as a debugging tool",
  95                 "ensure to avoid having uses of it in version control",
  96                 suggestion,
  97                 applicability,
  98             );
  99         }
 100     }
 101 }