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

charon_lib/
errors.rs
