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

charon_lib/
errors.rs
