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Add missing_panics_doc lint

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Caden Haustein 2020-12-30 16:37:59 -06:00 • committed by flip1995
parent f870876d92
commit bde667af7e
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GPG key ID: 1CA0DF2AF59D68A5
16 changed files with 346 additions and 38 deletions
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125
clippy_lints/src/doc.rs
View file

@ -1,4 +1,7 @@
use crate::utils::{implements_trait, is_entrypoint_fn, is_type_diagnostic_item, return_ty, span_lint};
use crate::utils::{
implements_trait, is_entrypoint_fn, is_type_diagnostic_item, match_panic_def_id, method_chain_args, return_ty,
span_lint, span_lint_and_note,
};
use if_chain::if_chain;
use itertools::Itertools;
use rustc_ast::ast::{Async, AttrKind, Attribute, FnRetTy, ItemKind};
@ -8,7 +11,10 @@ use rustc_data_structures::sync::Lrc;
use rustc_errors::emitter::EmitterWriter;
use rustc_errors::Handler;
use rustc_hir as hir;
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::{Expr, ExprKind, QPath};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::hir::map::Map;
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty;
use rustc_parse::maybe_new_parser_from_source_str;
@ -122,6 +128,37 @@ declare_clippy_lint! {
"`pub fn` returns `Result` without `# Errors` in doc comment"
}
declare_clippy_lint! {
/// **What it does:** Checks the doc comments of publicly visible functions that
/// may panic and warns if there is no `# Panics` section.
///
/// **Why is this bad?** Documenting the scenarios in which panicking occurs
/// can help callers who do not want to panic to avoid those situations.
///
/// **Known problems:** None.
///
/// **Examples:**
///
/// Since the following function may panic it has a `# Panics` section in
/// its doc comment:
///
/// ```rust
/// /// # Panics
/// ///
/// /// Will panic if y is 0
/// pub fn divide_by(x: i32, y: i32) -> i32 {
/// if y == 0 {
/// panic!("Cannot divide by 0")
/// } else {
/// x / y
/// }
/// }
/// ```
pub MISSING_PANICS_DOC,
pedantic,
"`pub fn` may panic without `# Panics` in doc comment"
}
declare_clippy_lint! {
/// **What it does:** Checks for `fn main() { .. }` in doctests
///
@ -166,7 +203,9 @@ impl DocMarkdown {
}
}
impl_lint_pass!(DocMarkdown => [DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, NEEDLESS_DOCTEST_MAIN]);
impl_lint_pass!(DocMarkdown =>
[DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, MISSING_PANICS_DOC, NEEDLESS_DOCTEST_MAIN]
);
impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
fn check_crate(&mut self, cx: &LateContext<'tcx>, krate: &'tcx hir::Crate<'_>) {
@ -180,7 +219,15 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
if !(is_entrypoint_fn(cx, cx.tcx.hir().local_def_id(item.hir_id).to_def_id())
|| in_external_macro(cx.tcx.sess, item.span))
{
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
let body = cx.tcx.hir().body(body_id);
let impl_item_def_id = cx.tcx.hir().local_def_id(item.hir_id);
let mut fpu = FindPanicUnwrap {
cx,
typeck_results: cx.tcx.typeck(impl_item_def_id),
panic_span: None,
};
fpu.visit_expr(&body.value);
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
}
},
hir::ItemKind::Impl(ref impl_) => {
@ -200,7 +247,7 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
if let hir::TraitItemKind::Fn(ref sig, ..) = item.kind {
if !in_external_macro(cx.tcx.sess, item.span) {
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None);
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None, None);
}
}
}
@ -211,7 +258,15 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
return;
}
if let hir::ImplItemKind::Fn(ref sig, body_id) = item.kind {
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
let body = cx.tcx.hir().body(body_id);
let impl_item_def_id = cx.tcx.hir().local_def_id(item.hir_id);
let mut fpu = FindPanicUnwrap {
cx,
typeck_results: cx.tcx.typeck(impl_item_def_id),
panic_span: None,
};
fpu.visit_expr(&body.value);
lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
}
}
}
@ -223,6 +278,7 @@ fn lint_for_missing_headers<'tcx>(
sig: &hir::FnSig<'_>,
headers: DocHeaders,
body_id: Option<hir::BodyId>,
panic_span: Option<Span>,
) {
if !cx.access_levels.is_exported(hir_id) {
return; // Private functions do not require doc comments
@ -235,6 +291,16 @@ fn lint_for_missing_headers<'tcx>(
"unsafe function's docs miss `# Safety` section",
);
}
if !headers.panics && panic_span.is_some() {
span_lint_and_note(
cx,
MISSING_PANICS_DOC,
span,
"docs for function which may panic missing `# Panics` section",
panic_span,
"first possible panic found here",
);
}
if !headers.errors {
if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::result_type) {
span_lint(
@ -321,6 +387,7 @@ pub fn strip_doc_comment_decoration(doc: &str, comment_kind: CommentKind, span:
struct DocHeaders {
safety: bool,
errors: bool,
panics: bool,
}
fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs: &'a [Attribute]) -> DocHeaders {
@ -338,6 +405,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
return DocHeaders {
safety: true,
errors: true,
panics: true,
};
}
}
@ -353,6 +421,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
return DocHeaders {
safety: false,
errors: false,
panics: false,
};
}
@ -394,6 +463,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
let mut headers = DocHeaders {
safety: false,
errors: false,
panics: false,
};
let mut in_code = false;
let mut in_link = None;
@ -439,6 +509,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
}
headers.safety |= in_heading && text.trim() == "Safety";
headers.errors |= in_heading && text.trim() == "Errors";
headers.panics |= in_heading && text.trim() == "Panics";
let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
Ok(o) => o,
Err(e) => e - 1,
@ -607,3 +678,47 @@ fn check_word(cx: &LateContext<'_>, word: &str, span: Span) {
);
}
}
struct FindPanicUnwrap<'a, 'tcx> {
cx: &'a LateContext<'tcx>,
panic_span: Option<Span>,
typeck_results: &'tcx ty::TypeckResults<'tcx>,
}
impl<'a, 'tcx> Visitor<'tcx> for FindPanicUnwrap<'a, 'tcx> {
type Map = Map<'tcx>;
fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
if self.panic_span.is_some() {
return;
}
// check for `begin_panic`
if_chain! {
if let ExprKind::Call(ref func_expr, _) = expr.kind;
if let ExprKind::Path(QPath::Resolved(_, ref path)) = func_expr.kind;
if let Some(path_def_id) = path.res.opt_def_id();
if match_panic_def_id(self.cx, path_def_id);
then {
self.panic_span = Some(expr.span);
}
}
// check for `unwrap`
if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
let reciever_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
if is_type_diagnostic_item(self.cx, reciever_ty, sym::option_type)
|| is_type_diagnostic_item(self.cx, reciever_ty, sym::result_type)
{
self.panic_span = Some(expr.span);
}
}
// and check sub-expressions
intravisit::walk_expr(self, expr);
}
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
}
}

2
clippy_lints/src/lib.rs
View file

@ -592,6 +592,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
&disallowed_method::DISALLOWED_METHOD,
&doc::DOC_MARKDOWN,
&doc::MISSING_ERRORS_DOC,
&doc::MISSING_PANICS_DOC,
&doc::MISSING_SAFETY_DOC,
&doc::NEEDLESS_DOCTEST_MAIN,
&double_comparison::DOUBLE_COMPARISONS,
@ -1317,6 +1318,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(&derive::UNSAFE_DERIVE_DESERIALIZE),
LintId::of(&doc::DOC_MARKDOWN),
LintId::of(&doc::MISSING_ERRORS_DOC),
LintId::of(&doc::MISSING_PANICS_DOC),
LintId::of(&empty_enum::EMPTY_ENUM),
LintId::of(&enum_variants::MODULE_NAME_REPETITIONS),
LintId::of(&enum_variants::PUB_ENUM_VARIANT_NAMES),

2
clippy_lints/src/utils/diagnostics.rs
View file

@ -110,7 +110,7 @@ pub fn span_lint_and_help<'a, T: LintContext>(
pub fn span_lint_and_note<'a, T: LintContext>(
cx: &'a T,
lint: &'static Lint,
span: Span,
span: impl Into<MultiSpan>,
msg: &str,
note_span: Option<Span>,
note: &str,