diff options
Diffstat (limited to 'src/librustdoc/passes/lint/check_code_block_syntax.rs')
-rw-r--r-- | src/librustdoc/passes/lint/check_code_block_syntax.rs | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/librustdoc/passes/lint/check_code_block_syntax.rs b/src/librustdoc/passes/lint/check_code_block_syntax.rs new file mode 100644 index 000000000..5aa4f238b --- /dev/null +++ b/src/librustdoc/passes/lint/check_code_block_syntax.rs @@ -0,0 +1,170 @@ +//! Validates syntax inside Rust code blocks (\`\`\`rust). +use rustc_data_structures::sync::{Lock, Lrc}; +use rustc_errors::{ + emitter::Emitter, + translation::{to_fluent_args, Translate}, + Applicability, Diagnostic, Handler, LazyFallbackBundle, +}; +use rustc_parse::parse_stream_from_source_str; +use rustc_session::parse::ParseSess; +use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId}; +use rustc_span::source_map::{FilePathMapping, SourceMap}; +use rustc_span::{FileName, InnerSpan, DUMMY_SP}; + +use crate::clean; +use crate::core::DocContext; +use crate::html::markdown::{self, RustCodeBlock}; +use crate::passes::source_span_for_markdown_range; + +pub(crate) fn visit_item(cx: &DocContext<'_>, item: &clean::Item) { + if let Some(dox) = &item.attrs.collapsed_doc_value() { + let sp = item.attr_span(cx.tcx); + let extra = + crate::html::markdown::ExtraInfo::new_did(cx.tcx, item.item_id.expect_def_id(), sp); + for code_block in markdown::rust_code_blocks(dox, &extra) { + check_rust_syntax(cx, item, dox, code_block); + } + } +} + +fn check_rust_syntax( + cx: &DocContext<'_>, + item: &clean::Item, + dox: &str, + code_block: RustCodeBlock, +) { + let buffer = Lrc::new(Lock::new(Buffer::default())); + let fallback_bundle = + rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false); + let emitter = BufferEmitter { buffer: Lrc::clone(&buffer), fallback_bundle }; + + let sm = Lrc::new(SourceMap::new(FilePathMapping::empty())); + let handler = Handler::with_emitter(false, None, Box::new(emitter)); + let source = dox[code_block.code].to_owned(); + let sess = ParseSess::with_span_handler(handler, sm); + + let edition = code_block.lang_string.edition.unwrap_or_else(|| cx.tcx.sess.edition()); + let expn_data = + ExpnData::default(ExpnKind::AstPass(AstPass::TestHarness), DUMMY_SP, edition, None, None); + let expn_id = cx.tcx.with_stable_hashing_context(|hcx| LocalExpnId::fresh(expn_data, hcx)); + let span = DUMMY_SP.fresh_expansion(expn_id); + + let is_empty = rustc_driver::catch_fatal_errors(|| { + parse_stream_from_source_str( + FileName::Custom(String::from("doctest")), + source, + &sess, + Some(span), + ) + .is_empty() + }) + .unwrap_or(false); + let buffer = buffer.borrow(); + + if !buffer.has_errors && !is_empty { + // No errors in a non-empty program. + return; + } + + let Some(local_id) = item.item_id.as_def_id().and_then(|x| x.as_local()) + else { + // We don't need to check the syntax for other crates so returning + // without doing anything should not be a problem. + return; + }; + + let hir_id = cx.tcx.hir().local_def_id_to_hir_id(local_id); + let empty_block = code_block.lang_string == Default::default() && code_block.is_fenced; + let is_ignore = code_block.lang_string.ignore != markdown::Ignore::None; + + // The span and whether it is precise or not. + let (sp, precise_span) = + match source_span_for_markdown_range(cx.tcx, dox, &code_block.range, &item.attrs) { + Some(sp) => (sp, true), + None => (item.attr_span(cx.tcx), false), + }; + + let msg = if buffer.has_errors { + "could not parse code block as Rust code" + } else { + "Rust code block is empty" + }; + + // Finally build and emit the completed diagnostic. + // All points of divergence have been handled earlier so this can be + // done the same way whether the span is precise or not. + cx.tcx.struct_span_lint_hir(crate::lint::INVALID_RUST_CODEBLOCKS, hir_id, sp, msg, |lint| { + let explanation = if is_ignore { + "`ignore` code blocks require valid Rust code for syntax highlighting; \ + mark blocks that do not contain Rust code as text" + } else { + "mark blocks that do not contain Rust code as text" + }; + + if precise_span { + if is_ignore { + // giving an accurate suggestion is hard because `ignore` might not have come first in the list. + // just give a `help` instead. + lint.span_help( + sp.from_inner(InnerSpan::new(0, 3)), + &format!("{}: ```text", explanation), + ); + } else if empty_block { + lint.span_suggestion( + sp.from_inner(InnerSpan::new(0, 3)).shrink_to_hi(), + explanation, + "text", + Applicability::MachineApplicable, + ); + } + } else if empty_block || is_ignore { + lint.help(&format!("{}: ```text", explanation)); + } + + // FIXME(#67563): Provide more context for these errors by displaying the spans inline. + for message in buffer.messages.iter() { + lint.note(message); + } + + lint + }); +} + +#[derive(Default)] +struct Buffer { + messages: Vec<String>, + has_errors: bool, +} + +struct BufferEmitter { + buffer: Lrc<Lock<Buffer>>, + fallback_bundle: LazyFallbackBundle, +} + +impl Translate for BufferEmitter { + fn fluent_bundle(&self) -> Option<&Lrc<rustc_errors::FluentBundle>> { + None + } + + fn fallback_fluent_bundle(&self) -> &rustc_errors::FluentBundle { + &**self.fallback_bundle + } +} + +impl Emitter for BufferEmitter { + fn emit_diagnostic(&mut self, diag: &Diagnostic) { + let mut buffer = self.buffer.borrow_mut(); + + let fluent_args = to_fluent_args(diag.args()); + let translated_main_message = self.translate_message(&diag.message[0].0, &fluent_args); + + buffer.messages.push(format!("error from rustc: {}", translated_main_message)); + if diag.is_error() { + buffer.has_errors = true; + } + } + + fn source_map(&self) -> Option<&Lrc<SourceMap>> { + None + } +} |