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, 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, PartialEq, Eq, Clone, Serialize, Deserialize)]
60pub struct Error {
61    pub span: Span,
62    pub msg: String,
63}
64
65impl Error {
66    pub fn new(span: Span, msg: String) -> Self {
67        Self { span, msg }
68    }
69    pub fn dummy() -> Self {
70        Self {
71            span: Span::dummy(),
72            msg: String::new(),
73        }
74    }
75
76    pub(crate) fn render(&self, krate: &TranslatedCrate, level: Level) -> String {
77        use annotate_snippets::*;
78        let span = self.span.data;
79
80        let mut group = Group::with_title(level.primary_title(&self.msg));
81        let origin;
82        if let Some(file) = krate.files.get(span.file_id) {
83            origin = format!("{}", file.name);
84            if let Some(source) = &file.contents {
85                let snippet = Snippet::source(source)
86                    .path(&origin)
87                    .fold(true)
88                    .annotation(AnnotationKind::Primary.span(span.to_byte_range(source)));
89                group = group.element(snippet);
90            } else {
91                // Show just the file and line/col.
92                let origin = Origin::path(&origin)
93                    .line(span.beg.line)
94                    .char_column(span.beg.col + 1);
95                group = group.element(origin);
96            }
97        }
98
99        Renderer::styled().render(&[group]).to_string()
100    }
101}
102
103impl<T: ToString> From<T> for Error {
104    fn from(err: T) -> Self {
105        Self {
106            span: Span::dummy(),
107            msg: err.to_string(),
108        }
109    }
110}
111
112/// Display an error without a specific location.
113pub fn display_unspanned_error(level: Level, msg: &str) {
114    use annotate_snippets::*;
115    let title = level.primary_title(msg);
116    let message = Renderer::styled()
117        .render(&[Group::with_title(title)])
118        .to_string();
119    anstream::eprintln!("{message}\n");
120}
121
122/// We use this to save the origin of an id. This is useful for the external
123/// dependencies, especially if some external dependencies don't extract:
124/// we use this information to tell the user what is the code which
125/// (transitively) lead to the extraction of those problematic dependencies.
126#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
127pub struct DepSource {
128    pub src_id: ItemId,
129    /// The location where the id was referred to. We store `None` for external dependencies as we
130    /// don't want to show these to the users.
131    pub span: Option<Span>,
132}
133
134/// For tracing error dependencies.
135#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, VariantIndexArity)]
136enum DepNode {
137    External(ItemId),
138    /// We use the span information only for local references
139    Local(ItemId, Span),
140}
141
142/// Graph of dependencies between erroring definitions and the definitions they came from.
143struct DepGraph {
144    dgraph: DiGraphMap<DepNode, ()>,
145}
146
147impl DepGraph {
148    fn new() -> Self {
149        DepGraph {
150            dgraph: DiGraphMap::new(),
151        }
152    }
153
154    fn insert_node(&mut self, n: DepNode) {
155        // We have to be careful about duplicate nodes
156        if !self.dgraph.contains_node(n) {
157            self.dgraph.add_node(n);
158        }
159    }
160
161    fn insert_edge(&mut self, from: DepNode, to: DepNode) {
162        self.insert_node(from);
163        self.insert_node(to);
164        if !self.dgraph.contains_edge(from, to) {
165            self.dgraph.add_edge(from, to, ());
166        }
167    }
168}
169
170impl std::fmt::Display for DepGraph {
171    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
172        for (from, to, _) in self.dgraph.all_edges() {
173            writeln!(f, "{from:?} -> {to:?}")?
174        }
175        Ok(())
176    }
177}
178
179/// The context for tracking and reporting errors.
180pub struct ErrorCtx {
181    /// If true, do not abort on the first error and attempt to extract as much as possible.
182    pub continue_on_failure: bool,
183    /// If true, print the warnings as errors, and abort if any errors were raised.
184    pub error_on_warnings: bool,
185
186    /// The ids of the external_declarations for which extraction we encountered errors.
187    pub external_decls_with_errors: HashSet<ItemId>,
188    /// Graph of dependencies between items: there is an edge from item `a` to item `b` if `b`
189    /// registered the id for `a` during its translation. Because we only use this to report errors
190    /// on external items, we only record edges where `a` is an external item.
191    external_dep_graph: DepGraph,
192    /// The id of the definition we are exploring, used to track the source of errors.
193    pub def_id: Option<ItemId>,
194    /// Whether the definition being explored is local to the crate or not.
195    pub def_id_is_local: bool,
196    /// The number of errors encountered so far.
197    pub error_count: usize,
198}
199
200impl ErrorCtx {
201    pub fn new() -> Self {
202        Self {
203            continue_on_failure: true,
204            error_on_warnings: false,
205            external_decls_with_errors: HashSet::new(),
206            external_dep_graph: DepGraph::new(),
207            def_id: None,
208            def_id_is_local: false,
209            error_count: 0,
210        }
211    }
212
213    pub fn continue_on_failure(&self) -> bool {
214        self.continue_on_failure
215    }
216    pub fn has_errors(&self) -> bool {
217        self.error_count > 0
218    }
219
220    /// Report an error without registering anything.
221    pub fn display_error(
222        &self,
223        krate: &TranslatedCrate,
224        span: Span,
225        level: Level,
226        msg: String,
227    ) -> Error {
228        let error = Error { span, msg };
229        anstream::eprintln!("{}\n", error.render(krate, level));
230        if BACKTRACE_ON_ERR {
231            let backtrace = std::backtrace::Backtrace::force_capture();
232            eprintln!("{backtrace}\n");
233        }
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: ItemId,
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: ItemId) {
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.data.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.data.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.primary_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
