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

charon_lib/
errors.rs
