charon_lib/
errors.rs

1//! Utilities to generate error reports about the external dependencies.
2use crate::ast::*;
3use crate::formatter::IntoFormatter;
4use crate::pretty::FmtWithCtx;
5pub use annotate_snippets::Level;
6use itertools::Itertools;
7use macros::VariantIndexArity;
8use petgraph::algo::dijkstra::dijkstra;
9use petgraph::prelude::DiGraphMap;
10use rustc_hash::FxHashSet as HashSet;
11use serde::{Deserialize, Serialize};
12use std::cmp::{Ord, PartialOrd};
13
14const BACKTRACE_ON_ERR: bool = false;
15
16#[macro_export]
17macro_rules! register_error {
18    ($ctx:expr, crate($krate:expr), $span: expr, $($fmt:tt)*) => {{
19        let msg = format!($($fmt)*);
20        $ctx.span_err($krate, $span, &msg, $crate::errors::Level::WARNING)
21    }};
22    ($ctx:expr, no_crate, $($fmt:tt)*) => {{
23        let msg = format!($($fmt)*);
24        $ctx.span_err(&Default::default(), Default::default(), &msg, $crate::errors::Level::WARNING)
25    }};
26    ($ctx:expr, $span: expr, $($fmt:tt)*) => {{
27        let msg = format!($($fmt)*);
28        $ctx.span_err($span, &msg, $crate::errors::Level::WARNING)
29    }};
30}
31pub use register_error;
32
33/// Macro to either panic or return on error, depending on the CLI options
34#[macro_export]
35macro_rules! raise_error {
36    ($($tokens:tt)*) => {{
37        return Err(register_error!($($tokens)*));
38    }};
39}
40pub use raise_error;
41
42/// Custom assert to either panic or return an error
43#[macro_export]
44macro_rules! error_assert {
45    ($ctx:expr, $span: expr, $b: expr) => {
46        if !$b {
47            $crate::errors::raise_error!($ctx, $span, "assertion failure: {:?}", stringify!($b));
48        }
49    };
50    ($ctx:expr, $span: expr, $b: expr, $($fmt:tt)*) => {
51        if !$b {
52            $crate::errors::raise_error!($ctx, $span, $($fmt)*);
53        }
54    };
55}
56pub use error_assert;
57
58/// Common error used during the translation.
59#[derive(Debug, Clone, PartialEq, Eq)]
60#[derive(Serialize, Deserialize)]
61pub struct Error {
62    pub span: Span,
63    pub msg: String,
64}
65
66impl Error {
67    pub fn new(span: Span, msg: String) -> Self {
68        Self { span, msg }
69    }
70    pub fn dummy() -> Self {
71        Self {
72            span: Span::dummy(),
73            msg: String::new(),
74        }
75    }
76
77    pub(crate) fn render(&self, krate: &TranslatedCrate, level: Level) -> String {
78        use annotate_snippets::*;
79        let span = self.span.data();
80
81        let mut group = Group::with_title(level.primary_title(&self.msg));
82        let origin;
83        if let Some(file) = krate.files.get(span.file_id) {
84            origin = format!("{}", file.name);
85            if let Some(source) = &file.contents {
86                let snippet = Snippet::source(source)
87                    .path(&origin)
88                    .fold(true)
89                    .annotation(AnnotationKind::Primary.span(span.to_byte_range(source)));
90                group = group.element(snippet);
91            } else {
92                // Show just the file and line/col.
93                let origin = Origin::path(&origin)
94                    .line(span.beg.line as usize)
95                    .char_column(span.beg.col as usize + 1);
96                group = group.element(origin);
97            }
98        }
99
100        Renderer::styled().render(&[group]).to_string()
101    }
102}
103
104impl<T: ToString> From<T> for Error {
105    fn from(err: T) -> Self {
106        Self {
107            span: Span::dummy(),
108            msg: err.to_string(),
109        }
110    }
111}
112
113/// Display an error without a specific location.
114pub fn display_unspanned_error(level: Level, msg: &str) {
115    use annotate_snippets::*;
116    let title = level.primary_title(msg);
117    let message = Renderer::styled()
118        .render(&[Group::with_title(title)])
119        .to_string();
120    anstream::eprintln!("{message}\n");
121}
122
123/// Display an error at the given source span.
124pub fn display_spanned_error(krate: &TranslatedCrate, span: Span, title: &str, label: &str) {
125    use annotate_snippets::*;
126
127    let span = span.data();
128    let mut group = Group::with_title(Level::ERROR.primary_title(title));
129    let origin;
130    if let Some(file) = krate.files.get(span.file_id) {
131        origin = file.name.to_string();
132        if let Some(source) = &file.contents {
133            let snippet = Snippet::source(source).path(&origin).annotation(
134                AnnotationKind::Primary
135                    .span(span.to_byte_range(source))
136                    .label(label),
137            );
138            group = group.element(snippet);
139        } else {
140            let origin = Origin::path(origin)
141                .line(span.beg.line as usize)
142                .char_column(span.beg.col as usize + 1);
143            group = group.element(origin);
144        }
145    }
146
147    let diagnostic = [group];
148    anstream::eprintln!("{}", Renderer::styled().render(&diagnostic));
149}
150
151/// We use this to save the origin of an id. This is useful for the external
152/// dependencies, especially if some external dependencies don't extract:
153/// we use this information to tell the user what is the code which
154/// (transitively) lead to the extraction of those problematic dependencies.
155#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
156pub struct DepSource {
157    pub src_id: ItemId,
158    /// The location where the id was referred to. We store `None` for external dependencies as we
159    /// don't want to show these to the users.
160    pub span: Option<Span>,
161}
162
163/// For tracing error dependencies.
164#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
165#[derive(VariantIndexArity)]
166enum DepNode {
167    External(ItemId),
168    /// We use the span information only for local references
169    Local(ItemId, Span),
170}
171
172/// Graph of dependencies between erroring definitions and the definitions they came from.
173struct DepGraph {
174    edges: HashSet<(DepNode, DepNode)>,
175}
176
177impl DepGraph {
178    fn new() -> Self {
179        DepGraph {
180            edges: Default::default(),
181        }
182    }
183
184    fn insert_edge(&mut self, from: DepNode, to: DepNode) {
185        self.edges.insert((from, to));
186    }
187
188    fn graph(&self) -> DiGraphMap<DepNode, (), rustc_hash::FxBuildHasher> {
189        DiGraphMap::from_edges(self.edges.iter().copied())
190    }
191}
192
193/// The context for tracking and reporting errors.
194pub struct ErrorCtx {
195    /// If true, do not abort on the first error and attempt to extract as much as possible.
196    pub continue_on_failure: bool,
197    /// If true, print the warnings as errors, and abort if any errors were raised.
198    pub error_on_warnings: bool,
199
200    /// The ids of the items for which extraction encountered errors.
201    items_with_errors: HashSet<ItemId>,
202    /// Graph of dependencies between items: there is an edge from item `a` to item `b` if `b`
203    /// registered the id for `a` during its translation. Because we only use this to report errors
204    /// on external items, we only record edges where `a` is an external item.
205    external_dep_graph: DepGraph,
206    /// The id of the definition we are exploring, used to track the source of errors.
207    pub def_id: Option<ItemId>,
208    /// Whether the definition being explored is local to the crate or not.
209    pub def_id_is_local: bool,
210    /// The number of errors encountered so far.
211    pub error_count: usize,
212}
213
214impl ErrorCtx {
215    pub fn new() -> Self {
216        Self {
217            continue_on_failure: true,
218            error_on_warnings: false,
219            items_with_errors: HashSet::default(),
220            external_dep_graph: DepGraph::new(),
221            def_id: None,
222            def_id_is_local: false,
223            error_count: 0,
224        }
225    }
226
227    pub fn continue_on_failure(&self) -> bool {
228        self.continue_on_failure
229    }
230    pub fn has_errors(&self) -> bool {
231        self.error_count > 0
232    }
233    pub fn item_has_errors(&self, id: ItemId) -> bool {
234        self.items_with_errors.contains(&id)
235    }
236
237    /// Report an error without registering anything.
238    pub fn display_error(
239        &self,
240        krate: &TranslatedCrate,
241        span: Span,
242        level: Level,
243        msg: String,
244    ) -> Error {
245        let error = Error { span, msg };
246        anstream::eprintln!("{}\n", error.render(krate, level));
247        if BACKTRACE_ON_ERR {
248            let backtrace = std::backtrace::Backtrace::force_capture();
249            eprintln!("{backtrace}\n");
250        }
251        error
252    }
253
254    /// Report and register an error.
255    pub fn span_err(
256        &mut self,
257        krate: &TranslatedCrate,
258        span: Span,
259        msg: &str,
260        level: Level,
261    ) -> Error {
262        let level = if level == Level::WARNING && self.error_on_warnings {
263            Level::ERROR
264        } else {
265            level
266        };
267        let err = self.display_error(krate, span, level, msg.to_string());
268        self.error_count += 1;
269        if let Some(id) = self.def_id
270            && self.items_with_errors.insert(id)
271            && !self.def_id_is_local
272        {
273            // If this item comes from an external crate, after the first error for that item
274            // we display where in the local crate that item was reached from.
275            self.report_external_dep_error(krate, id);
276        }
277        if !self.continue_on_failure() {
278            panic!("{msg}");
279        }
280        err
281    }
282
283    /// Register the fact that `id` is a dependency of `src` (if `src` is not `None`).
284    pub fn register_dep_source(
285        &mut self,
286        src: &Option<DepSource>,
287        item_id: ItemId,
288        is_local: bool,
289    ) {
290        if let Some(src) = src
291            && src.src_id != item_id
292            && !is_local
293        {
294            let src_node = DepNode::External(item_id);
295            let tgt_node = match src.span {
296                Some(span) => DepNode::Local(src.src_id, span),
297                None => DepNode::External(src.src_id),
298            };
299            self.external_dep_graph.insert_edge(src_node, tgt_node)
300        }
301    }
302
303    /// In case errors happened when extracting the definitions coming from the external
304    /// dependencies, print a detailed report to explain to the user which dependencies were
305    /// problematic, and where they are used in the code.
306    pub fn report_external_dep_error(&self, krate: &TranslatedCrate, id: ItemId) {
307        use annotate_snippets::*;
308
309        // Use `Dijkstra's` algorithm to find the local items reachable from the current non-local
310        // item.
311        let graph = self.external_dep_graph.graph();
312        let reachable = dijkstra(&graph, DepNode::External(id), None, |_| 1);
313        trace!("id: {:?}\nreachable:\n{:?}", id, reachable);
314
315        // Collect reachable local spans.
316        let by_file: std::collections::HashMap<FileId, Vec<Span>> = reachable
317            .iter()
318            .filter_map(|(n, _)| match n {
319                DepNode::External(_) => None,
320                DepNode::Local(_, span) => Some(*span),
321            })
322            .into_group_map_by(|span| span.data().file_id);
323
324        // Collect to a `Vec` to be able to sort it and to borrow `origin` (needed by
325        // `Snippet::source`).
326        let mut by_file: Vec<(FileId, _, _, Vec<Span>)> = by_file
327            .into_iter()
328            .filter_map(|(file_id, mut spans)| {
329                spans.sort(); // Sort spans to display in file order
330                let file = krate.files.get(file_id)?;
331                let source = file.contents.as_ref()?;
332                let file_name = file.name.to_string();
333                Some((file_id, file_name, source, spans))
334            })
335            .collect();
336        // Sort by file id to avoid output instability.
337        by_file.sort_by_key(|(file_id, ..)| *file_id);
338
339        let level = Level::NOTE;
340        let snippets =
341            by_file.iter().map(|(_, origin, source, spans)| {
342                Snippet::source(*source)
343                    .path(origin)
344                    .fold(true)
345                    .annotations(spans.iter().map(|span| {
346                        AnnotationKind::Context.span(span.data().to_byte_range(source))
347                    }))
348            });
349
350        let msg = format!(
351            "the error occurred when translating `{}`, \
352             which is (transitively) used at the following location(s):",
353            id.with_ctx(&krate.into_fmt())
354        );
355        let message = Group::with_title(level.primary_title(&msg)).elements(snippets);
356        let out = Renderer::styled().render(&[message]).to_string();
357        anstream::eprintln!("{}", out);
358    }
359}
charon_lib/errors.rs

charon_lib/
errors.rs
