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     /// // Bad
  22     /// dbg!(true)
  23     ///
  24     /// // Good
  25     /// true
  26     /// ```
  27     #[clippy::version = "1.34.0"]
  28     pub DBG_MACRO,
  29     restriction,
  30     "`dbg!` macro is intended as a debugging tool"
  31 }
  32
  33 #[derive(Copy, Clone)]
  34 pub struct DbgMacro {
  35     allow_dbg_in_tests: bool,
  36 }
  37
  38 impl_lint_pass!(DbgMacro => [DBG_MACRO]);
  39
  40 impl DbgMacro {
  41     pub fn new(allow_dbg_in_tests: bool) -> Self {
  42         DbgMacro { allow_dbg_in_tests }
  43     }
  44 }
  45
  46 impl LateLintPass<'_> for DbgMacro {
  47     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
  48         let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return };
  49         if cx.tcx.is_diagnostic_item(sym::dbg_macro, macro_call.def_id) {
  50             // allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
  51             if self.allow_dbg_in_tests
  52                 && (is_in_test_function(cx.tcx, expr.hir_id) || is_in_cfg_test(cx.tcx, expr.hir_id))
  53             {
  54                 return;
  55             }
  56             let mut applicability = Applicability::MachineApplicable;
  57             let suggestion = match expr.peel_drop_temps().kind {
  58                 // dbg!()
  59                 ExprKind::Block(_, _) => String::new(),
  60                 // dbg!(1)
  61                 ExprKind::Match(val, ..) => {
  62                     snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability).to_string()
  63                 },
  64                 // dbg!(2, 3)
  65                 ExprKind::Tup(
  66                     [
  67                         Expr {
  68                             kind: ExprKind::Match(first, ..),
  69                             ..
  70                         },
  71                         ..,
  72                         Expr {
  73                             kind: ExprKind::Match(last, ..),
  74                             ..
  75                         },
  76                     ],
  77                 ) => {
  78                     let snippet = snippet_with_applicability(
  79                         cx,
  80                         first.span.source_callsite().to(last.span.source_callsite()),
  81                         "..",
  82                         &mut applicability,
  83                     );
  84                     format!("({snippet})")
  85                 },
  86                 _ => return,
  87             };
  88
  89             span_lint_and_sugg(
  90                 cx,
  91                 DBG_MACRO,
  92                 macro_call.span,
  93                 "`dbg!` macro is intended as a debugging tool",
  94                 "ensure to avoid having uses of it in version control",
  95                 suggestion,
  96                 applicability,
  97             );
  98         }
  99     }
 100 }