SpannedError: Store error span (#569)

* SpannedError: Store position start and position end in span

* Update CHANGELOG.md

Co-authored-by: Juniper Tyree <[email protected]>

* fix: SpannedError: fmt displays start and end of span if they differ

* fix: errant tests and formatting

* ci: Clean between Check/Clippy/Test

* test: Add helpers for Position and Span error checking, and use them in all unit tests that use non-trivial Spans

* fix: place unicode-segmentation and the Span::substring helpers behind an optional (non-default) feature, include substring Span checks in non-trivial integration tests

---------

Co-authored-by: Juniper Tyree <[email protected]>

Author: pfnsec

.github/workflows/ci.yaml

@@ -77,14 +77,20 @@ jobs:
       - name: Check
         run: |
           cargo hack check --feature-powerset --no-dev-deps
+      - name: Clean
+        run: |
+          cargo clean
       - name: Clippy
         run: |
           cargo hack clippy --feature-powerset --no-dev-deps -- -D warnings -A unknown-lints
         # Clippy will report lints that cannot be acted on without increasing MSRV on later versions of Rust
         if: ${{ matrix.rust == '1.64.0' }}
+      - name: Clean
+        run: |
+          cargo clean
       - name: Test
         run: |
-          cargo hack test --feature-powerset
+          cargo hack test --feature-powerset --clean-per-run
 
   clippy-fuzz:
     name: "Clippy: Fuzzer"

CHANGELOG.md

@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### API Changes
 
+- Breaking: `SpannedError` now stores the full error span in span: Span { start: Position, end: Position }`, to facilitate, e.g., language servers highlighting of syntax errors.
+
 - Breaking: Added `no_std` support via a new `std` feature (enabled by default). With default features disabled, you must enable the `std` feature to access `de::from_reader`, and the `std::io` operations on `Options`, such as `from_reader`, `from_reader_seed`, `to_io_writer`, and `to_io_writer_pretty` ([#567](https://github.com/ron-rs/ron/pull/567))
 
 ## [0.10.1] - 2025-04-08

Cargo.toml

@@ -24,6 +24,8 @@ default = ["std"]
 integer128 = []
 std = ["serde/std"]
 indexmap = ["std", "dep:indexmap"]
+# Note: this feature is a gate for internal error span tests and should not be enabled by users.
+internal-span-substring-test = ["unicode-segmentation"]
 
 [dependencies]
 # FIXME @juntyr remove base64 once old byte strings are fully deprecated
@@ -36,6 +38,7 @@ indexmap = { version = "2.0", default-features = false, features = ["serde"], op
 serde = { version = "1.0.181", default-features = false, features = ["alloc"] }
 serde_derive = { version = "1.0.181", default-features = false }
 unicode-ident = { version = "1.0", default-features = false }
+unicode-segmentation = { version = "1.12.0", optional = true, default-features = false }
 
 [dev-dependencies]
 serde = { version = "1.0.181", default-features = false, features = ["std", "derive"] }

src/de/mod.rs

@@ -11,7 +11,7 @@ use serde::{
     Deserialize,
 };
 
-pub use crate::error::{Error, Position, SpannedError};
+pub use crate::error::{Error, Position, Span, SpannedError};
 use crate::{
     error::{Result, SpannedResult},
     extensions::Extensions,
@@ -83,7 +83,10 @@ impl<'de> Deserializer<'de> {
 
         Err(SpannedError {
             code: err.into(),
-            position: Position::from_src_end(valid_input),
+            span: Span {
+                start: Position { line: 1, col: 1 },
+                end: Position::from_src_end(valid_input),
+            },
         })
     }