Add new invalid_build_cfg lint
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| Original file line number | Diff line number | Diff line change | ||||
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| @@ -0,0 +1,308 @@ | ||||||
| use rustc_ast::ast::{Attribute, MacCall}; | ||||||
| use rustc_ast::token::{LitKind, TokenKind}; | ||||||
| use rustc_ast::tokenstream::{TokenStream, TokenTree}; | ||||||
| use rustc_ast::MetaItem; | ||||||
| use rustc_errors::Applicability; | ||||||
| use rustc_lint::{EarlyContext, EarlyLintPass, LintContext}; | ||||||
| use rustc_session::declare_lint_pass; | ||||||
| use rustc_span::{sym, Span, Symbol}; | ||||||
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| use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg}; | ||||||
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| declare_clippy_lint! { | ||||||
| /// ### What it does | ||||||
| /// Checks for usage of `#[cfg]`/`#[cfg_attr]`/`cfg!()` in `build.rs` scripts. | ||||||
| /// | ||||||
| /// ### Why is this bad? | ||||||
| /// It checks the `cfg` values for the *host*, not the target. For example, `cfg!(windows)` is | ||||||
| /// true when compiling on Windows, so it will give the wrong answer if you are cross compiling. | ||||||
| /// This is because build scripts run on the machine performing compilation, rather than on the | ||||||
| /// target. | ||||||
| /// | ||||||
| /// ### Example | ||||||
| /// ```no_run | ||||||
| /// if cfg!(windows) {} | ||||||
| /// ``` | ||||||
| /// Use instead: | ||||||
| /// ```no_run | ||||||
| /// if std::env::var("CARGO_CFG_WINDOWS").is_ok() {} | ||||||
| /// ``` | ||||||
| #[clippy::version = "1.80.0"] | ||||||
| pub INVALID_BUILD_CFG, | ||||||
| suspicious, | ||||||
| "invalid use of cfg in `build.rs`" | ||||||
|
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| } | ||||||
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| declare_lint_pass!(InvalidBuildCfg => [INVALID_BUILD_CFG]); | ||||||
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| #[derive(Debug)] | ||||||
| enum CfgAst { | ||||||
| Os(Symbol), | ||||||
| Any(Vec<CfgAst>), | ||||||
| All(Vec<CfgAst>), | ||||||
| Not(Box<CfgAst>), | ||||||
| TargetKeyValue(Symbol, Symbol), | ||||||
| Feature(Symbol), | ||||||
| OtherTarget(Symbol, Symbol), | ||||||
| } | ||||||
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There was a problem hiding this comment. Some documentation would be nice, it's not immediately clear why |
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| impl CfgAst { | ||||||
| fn has_only_features(&self) -> bool { | ||||||
| match self { | ||||||
| Self::Os(_) | Self::TargetKeyValue(_, _) | Self::OtherTarget(_, _) => false, | ||||||
| Self::Any(v) | Self::All(v) => v.is_empty() || v.iter().all(CfgAst::has_only_features), | ||||||
| Self::Not(v) => v.has_only_features(), | ||||||
| Self::Feature(_) => true, | ||||||
| } | ||||||
| } | ||||||
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| fn generate_replacement(&self) -> String { | ||||||
| self.generate_replacement_inner(true, false) | ||||||
| } | ||||||
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| fn generate_replacement_inner(&self, is_top_level: bool, parent_is_not: bool) -> String { | ||||||
| match self { | ||||||
| Self::Os(os) => format!( | ||||||
| "std::env::var(\"CARGO_CFG_{}\"){}", | ||||||
| os.as_str().to_uppercase(), | ||||||
| if parent_is_not { ".is_err()" } else { ".is_ok()" }, | ||||||
| ), | ||||||
| Self::TargetKeyValue(cfg_target, s) => format!( | ||||||
| "{}std::env::var(\"CARGO_CFG_{}\").unwrap_or_default() == \"{s}\"", | ||||||
| if parent_is_not { "!" } else { "" }, | ||||||
| cfg_target.as_str().to_uppercase(), | ||||||
| ), | ||||||
| Self::OtherTarget(cfg_target, s) => format!( | ||||||
| "{}std::env::var(\"CARGO_CFG_{}\").unwrap_or_default().split(',').any(|f| f == \"{s}\")", | ||||||
| if parent_is_not { "!" } else { "" }, | ||||||
| cfg_target.as_str().to_uppercase(), | ||||||
| ), | ||||||
| Self::Any(v) => { | ||||||
| if v.is_empty() { | ||||||
| if parent_is_not { "true" } else { "false" }.to_string() | ||||||
| } else if v.len() == 1 { | ||||||
| v[0].generate_replacement_inner(is_top_level, parent_is_not) | ||||||
| } else { | ||||||
| format!( | ||||||
| "{not}{open_paren}{cond}{closing_paren}", | ||||||
| not = if parent_is_not { "!" } else { "" }, | ||||||
| open_paren = if !parent_is_not && is_top_level { "" } else { "(" }, | ||||||
| cond = v | ||||||
| .iter() | ||||||
| .map(|i| i.generate_replacement_inner(false, false)) | ||||||
| .collect::<Vec<_>>() | ||||||
| .join(" || "), | ||||||
| closing_paren = if !parent_is_not && is_top_level { "" } else { ")" }, | ||||||
| ) | ||||||
| } | ||||||
| }, | ||||||
| Self::All(v) => { | ||||||
| if v.is_empty() { | ||||||
| if parent_is_not { "false" } else { "true" }.to_string() | ||||||
| } else if v.len() == 1 { | ||||||
| v[0].generate_replacement_inner(is_top_level, parent_is_not) | ||||||
| } else { | ||||||
| format!( | ||||||
| "{not}{open_paren}{cond}{closing_paren}", | ||||||
| not = if parent_is_not { "!" } else { "" }, | ||||||
| open_paren = if !parent_is_not && is_top_level { "" } else { "(" }, | ||||||
| cond = v | ||||||
| .iter() | ||||||
| .map(|i| i.generate_replacement_inner(false, false)) | ||||||
| .collect::<Vec<_>>() | ||||||
| .join(" && "), | ||||||
| closing_paren = if !parent_is_not && is_top_level { "" } else { ")" }, | ||||||
| ) | ||||||
| } | ||||||
| }, | ||||||
| Self::Not(i) => i.generate_replacement_inner(is_top_level, true), | ||||||
| Self::Feature(s) => format!( | ||||||
| "cfg!({}feature = {s}{})", | ||||||
| if parent_is_not { "not(" } else { "" }, | ||||||
| if parent_is_not { ")" } else { "" }, | ||||||
| ), | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| fn parse_macro_args(tokens: &TokenStream, has_unknown: &mut bool, out: &mut Vec<CfgAst>) { | ||||||
| let mut tokens = tokens.trees().peekable(); | ||||||
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| while let Some(token) = tokens.next() { | ||||||
| match token { | ||||||
| TokenTree::Token(token, _) => { | ||||||
| match token.kind { | ||||||
| TokenKind::Ident(name, _) => { | ||||||
| if name == sym::feature || name.as_str().starts_with("target_") { | ||||||
| if let Some(next_token) = tokens.next() | ||||||
| && let TokenTree::Token(next_token, _) = next_token | ||||||
| && matches!(next_token.kind, TokenKind::Eq) | ||||||
| && let Some(next_token) = tokens.next() | ||||||
| && let TokenTree::Token(next_token, _) = next_token | ||||||
| && let TokenKind::Literal(lit) = next_token.kind | ||||||
| && matches!(lit.kind, LitKind::Str | LitKind::StrRaw(_)) | ||||||
|
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There was a problem hiding this comment. Instead of all this custom parsing logic could it be possible to use |
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| { | ||||||
| if [ | ||||||
| sym::target_os, | ||||||
| sym::target_endian, | ||||||
| sym::target_pointer_width, | ||||||
| sym::target_vendor, | ||||||
| sym::target_has_atomic, | ||||||
| ] | ||||||
| .contains(&name) | ||||||
| { | ||||||
| out.push(CfgAst::TargetKeyValue(name, lit.symbol)); | ||||||
| } else if name == sym::feature { | ||||||
| out.push(CfgAst::Feature(lit.symbol)); | ||||||
| } else { | ||||||
| out.push(CfgAst::OtherTarget(name, lit.symbol)); | ||||||
| } | ||||||
| } else { | ||||||
| *has_unknown = true; | ||||||
| return; | ||||||
| } | ||||||
| } else if [sym::windows, sym::unix].contains(&name) { | ||||||
| out.push(CfgAst::Os(name)); | ||||||
| } else if [sym::any, sym::not, sym::all].contains(&name) { | ||||||
| let mut sub_out = Vec::new(); | ||||||
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| if let Some(next_token) = tokens.next() | ||||||
| && let TokenTree::Delimited(_, _, _, stream) = next_token | ||||||
| { | ||||||
| parse_macro_args(stream, has_unknown, &mut sub_out); | ||||||
| } else { | ||||||
| *has_unknown = true; | ||||||
| } | ||||||
| if *has_unknown { | ||||||
| // Could be set inside `parse_macro_args` too. | ||||||
| return; | ||||||
| } | ||||||
| if name == sym::any { | ||||||
| out.push(CfgAst::Any(sub_out)); | ||||||
| } else if name == sym::all { | ||||||
| out.push(CfgAst::All(sub_out)); | ||||||
| } else if sub_out.len() > 1 { | ||||||
| *has_unknown = true; | ||||||
| return; | ||||||
| } else if sub_out.len() == 1 { | ||||||
| out.push(CfgAst::Not(Box::new(sub_out.pop().unwrap()))); | ||||||
| } | ||||||
| } else { | ||||||
| *has_unknown = true; | ||||||
| return; | ||||||
| } | ||||||
| }, | ||||||
| TokenKind::Comma => {}, | ||||||
| _ => { | ||||||
| *has_unknown = true; | ||||||
| return; | ||||||
| }, | ||||||
| } | ||||||
| }, | ||||||
| TokenTree::Delimited(_, _, _, stream) => parse_macro_args(stream, has_unknown, out), | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| fn get_invalid_cfg_attrs(attr: &MetaItem, spans: &mut Vec<Span>, has_feature: &mut bool) { | ||||||
| let Some(ident) = attr.ident() else { return }; | ||||||
| if ident.name == sym::feature { | ||||||
| *has_feature = true; | ||||||
| return; | ||||||
| } | ||||||
| if attr.value_str().is_some() { | ||||||
| spans.push(attr.span); | ||||||
| } else if let Some(sub_attrs) = attr.meta_item_list() { | ||||||
| for sub_attr in sub_attrs { | ||||||
| if let Some(meta) = sub_attr.meta_item() { | ||||||
| get_invalid_cfg_attrs(meta, spans, has_feature); | ||||||
| } | ||||||
| } | ||||||
| } else { | ||||||
| spans.push(attr.span); | ||||||
| } | ||||||
| } | ||||||
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| fn is_build_script(cx: &EarlyContext<'_>) -> bool { | ||||||
| cx.sess() | ||||||
| .opts | ||||||
| .crate_name | ||||||
| .as_ref() | ||||||
| .map_or(false, |crate_name| crate_name == "build_script_build") | ||||||
| } | ||||||
|
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There was a problem hiding this comment. It would also be good to check if we are actually being called by Cargo. |
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| impl EarlyLintPass for InvalidBuildCfg { | ||||||
| fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &Attribute) { | ||||||
| if !is_build_script(cx) { | ||||||
| return; | ||||||
| } | ||||||
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| let name = attr.name_or_empty(); | ||||||
| let mut spans = Vec::new(); | ||||||
| let mut has_feature = false; | ||||||
| if name == sym::cfg { | ||||||
| if let Some(meta) = attr.meta() { | ||||||
| get_invalid_cfg_attrs(&meta, &mut spans, &mut has_feature); | ||||||
| } | ||||||
| } else if name == sym::cfg_attr { | ||||||
| if let Some(sub_attrs) = attr.meta_item_list() | ||||||
| && let Some(meta) = sub_attrs.first().and_then(|a| a.meta_item()) | ||||||
| { | ||||||
| get_invalid_cfg_attrs(meta, &mut spans, &mut has_feature); | ||||||
| } | ||||||
| } else { | ||||||
| return; | ||||||
| } | ||||||
| if !spans.is_empty() { | ||||||
| if has_feature { | ||||||
| // If the `cfg`/`cfg_attr` attribute contains not only invalid items, we display | ||||||
| // spans of all invalid items. | ||||||
| span_lint( | ||||||
| cx, | ||||||
| INVALID_BUILD_CFG, | ||||||
| spans, | ||||||
| format!("`{name}` attribute should not be used in `build.rs`"), | ||||||
| ); | ||||||
| } else { | ||||||
| // No "good" item in the `cfg`/`cfg_attr` attribute so we can use the span of the | ||||||
| // whole attribute directly. | ||||||
| span_lint( | ||||||
| cx, | ||||||
| INVALID_BUILD_CFG, | ||||||
| attr.span, | ||||||
| format!("`{name}` attribute should not be used in `build.rs`"), | ||||||
| ); | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| fn check_mac(&mut self, cx: &EarlyContext<'_>, call: &MacCall) { | ||||||
| if !is_build_script(cx) { | ||||||
| return; | ||||||
| } | ||||||
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| if call.path.segments.len() == 1 && call.path.segments[0].ident.name == sym::cfg { | ||||||
| let mut ast = Vec::new(); | ||||||
| let mut has_unknown = false; | ||||||
| parse_macro_args(&call.args.tokens, &mut has_unknown, &mut ast); | ||||||
| if has_unknown || ast.len() > 1 { | ||||||
| span_lint( | ||||||
| cx, | ||||||
| INVALID_BUILD_CFG, | ||||||
| call.span(), | ||||||
| "`cfg!` macro should not be used in `build.rs`", | ||||||
| ); | ||||||
| } else if !ast[0].has_only_features() { | ||||||
| span_lint_and_sugg( | ||||||
| cx, | ||||||
| INVALID_BUILD_CFG, | ||||||
| call.span(), | ||||||
| "`cfg!` macro should not be used in `build.rs`", | ||||||
| "use cargo environment variables if possible", | ||||||
| ast[0].generate_replacement(), | ||||||
| Applicability::MaybeIncorrect, | ||||||
| ); | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,30 @@ | ||
| // Should not emit the lint here! | ||
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| #![warn(clippy::invalid_build_cfg)] | ||
| #![allow(clippy::needless_if)] | ||
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| #[cfg(windows)] | ||
| fn unused_windows_fn() {} | ||
| #[cfg(not(windows))] | ||
| fn unused_not_windows_fn() {} | ||
| #[cfg(any(windows, feature = "yellow", unix))] | ||
| fn pink() {} | ||
| // Should not warn. | ||
| #[cfg(feature = "green")] | ||
| fn pink() {} | ||
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| fn main() { | ||
| if cfg!(windows) {} | ||
| if cfg!(not(windows)) {} | ||
| if cfg!(target_os = "freebsd") {} | ||
| if cfg!(any(target_os = "freebsd", windows)) {} | ||
| if cfg!(not(any(target_os = "freebsd", windows))) {} | ||
| if cfg!(all(target_os = "freebsd", windows)) {} | ||
| if cfg!(not(all(target_os = "freebsd", windows))) {} | ||
| if cfg!(all(target_os = "freebsd", any(windows, not(feature = "red")))) {} | ||
|
|
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| // Should not warn. | ||
|
There was a problem hiding this comment. Would also be good to add tests for custom cfgs, like |
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| if cfg!(any()) {} | ||
| if cfg!(all()) {} | ||
| if cfg!(feature = "blue") {} | ||
| } | ||
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Given that there are legitimate use cases for host-config in
build.rs, I think it would be better if the lint name acknowledges it. the linked issue proposedmisleading_cfg_in_build_script.