| use crate::utils::{is_direct_expn_of, span_lint_and_help}; |
| use if_chain::if_chain; |
| use rustc_ast::ast::{Expr, ExprKind}; |
| use rustc_lint::{EarlyContext, EarlyLintPass}; |
| use rustc_session::{declare_lint_pass, declare_tool_lint}; |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for usage of `option_env!(...).unwrap()` and |
| /// suggests usage of the `env!` macro. |
| /// |
| /// **Why is this bad?** Unwrapping the result of `option_env!` will panic |
| /// at run-time if the environment variable doesn't exist, whereas `env!` |
| /// catches it at compile-time. |
| /// |
| /// **Known problems:** None. |
| /// |
| /// **Example:** |
| /// |
| /// ```rust,no_run |
| /// let _ = option_env!("HOME").unwrap(); |
| /// ``` |
| /// |
| /// Is better expressed as: |
| /// |
| /// ```rust,no_run |
| /// let _ = env!("HOME"); |
| /// ``` |
| pub OPTION_ENV_UNWRAP, |
| correctness, |
| "using `option_env!(...).unwrap()` to get environment variable" |
| } |
| |
| declare_lint_pass!(OptionEnvUnwrap => [OPTION_ENV_UNWRAP]); |
| |
| impl EarlyLintPass for OptionEnvUnwrap { |
| fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { |
| if_chain! { |
| if let ExprKind::MethodCall(path_segment, args) = &expr.kind; |
| let method_name = path_segment.ident.as_str(); |
| if method_name == "expect" || method_name == "unwrap"; |
| if let ExprKind::Call(caller, _) = &args[0].kind; |
| if is_direct_expn_of(caller.span, "option_env").is_some(); |
| then { |
| span_lint_and_help( |
| cx, |
| OPTION_ENV_UNWRAP, |
| expr.span, |
| "this will panic at run-time if the environment variable doesn't exist at compile-time", |
| "consider using the `env!` macro instead" |
| ); |
| } |
| } |
| } |
| } |