Add no_std Support (#374)

* Switch to edition 2021 and resolver 2

This is effectively required for `no_std` support, as without it, dev-dependencies will enable features on regular dependencies, making it impossible to have `std` tests in `no_std` crates.

* Add useful `no_std` lints

These clippy lints highlight cases where an import is referencing `std` or `alloc` when it instead could import from `alloc` or `core`. This helps expose the "true" extent of `std` usage in a crate.

* Update dependencies and features

`termcolor` is incompatible with `no_std`, but `codespan` and `codespan-reporting` have valid use even without this crate. Making it optional allows `no_std` to be entirely decided by the contents of the codespan crates themselves.

Serde is also `no_std` compatible, as long as we disable default features.

* Increase MSRV to 1.67

During testing, `unicode-width` caused `cargo msrv find` to report `codespan-reporting`'s MSRV was 1.66, violating the current MSRV of 1.46. Since this is already the case, and there are features in 1.67, such as ilog10, which are desired within this crate, I have increased the MSRV to 1.67.

* Switch to derived `Default`

Before making substantive changes, `clippy` reported that these implementations for default can be derived. I have done so to silence the lint.

* Suppress `clippy::should_implement_trait`

`Span::from_str` shadows `FromStr::from_str`. Instead of breaking the public API, I added an explicit `allow`

* Remove redundant `into()` calls

Caught by clippy, and actioned to reduce warnings

* Suppress `clippy::too_many_arguments`

`Renderer::render_snippet_source` has too many arguments. Instead of breaking the public API, I'm suppressing this lint.

* Remove redundant references

These double-references are automatically dereferenced anyway.

* Use `ilog10` in `count_digits`

Increasing MSRV allows using the new `ilog10` method, solving a long-standing TODO

* Use of `format` is redundant

`ToString::to_string()` is preferred by `clippy` for converting `str` to `String`

* Simplify `assert_eq!` statements

`assert_eq` on a boolean is linted against by `clippy`, suggesting to use `assert!` instead.

* Implement `termcolor` feature gating

The `Styles` type is only needed for controlling colour, which is only needed with `termcolor`. Since we only deal with UTF8 strings, `std::fmt::Write` is equivalent to `WriteColor` when colour isn't required.

* Add `no_std` support

Switch imports to relying on `core` and `alloc`. `std::io::Write` can be replaced by `core::fmt::Write` since we deal exclusively with UTF8 strings.

* Added `check-no-std` to CI

This checks for `no_std` compatibility on 3 key targets:
- `x86_64-unknown-none`: represents desktop `no_std`, such as in kernels
- `wasm32v1-none`: represents Web builds using the most broadly support WASM target
-`thumbv6m-none-eabi`: represents typical embedded targets, such as the Raspberry Pi Pico

Testing on all three platforms ensures the widest possible compatibility.

* Fixes from CI run

- `cargo fmt`
- Fix typo in `ci.yml` which misused the matrix

* Switch from underscore to `allow(unused)`

Co-Authored-By: Ben <[email protected]>

* Document clippy lints

Co-Authored-By: Ben <[email protected]>

* Fix `check-no-std`

`wasm32v1-none` was only added in 1.84, so I've set that as the earliest Rust version used for testing `no_std` compatibility. Note that it's typical for embedded development to be done on nightly anyway, so `no_std` will usually happen on the very latest version of Rust.

* Format

* Remove  `serde/rc` from `codespan-reporting/serialization`

Not currently used and is incompatible with `thumbv6m-none-eabi`

* Test all combinations before giving up on `check-no-std`

Co-Authored-By: Ben <[email protected]>

---------

Co-authored-by: Ben <[email protected]>

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        rust: ["1.46.0", "stable", "beta", "nightly"]
+        rust: ["1.67.0", "stable", "beta", "nightly"]
     name: Check (${{ matrix.rust }})
     steps:
       - uses: actions/checkout@v2
@@ -53,11 +53,43 @@ jobs:
           command: check
           args: --manifest-path "codespan-lsp/Cargo.toml"
 
+  check-no-std:
+    name: Check
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: 
+          - "1.84.0"
+          - "stable"
+          - "beta"
+          - "nightly"
+        target:
+          - "x86_64-unknown-none"
+          - "wasm32v1-none"
+          - "thumbv6m-none-eabi"
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: ${{ matrix.rust }}
+          targets: ${{ matrix.target }}
+      - name: Run cargo check for codespan-reporting
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --manifest-path "codespan-reporting/Cargo.toml" --no-default-features --features "serialization" --target ${{ matrix.target }}
+      - name: Run cargo check for codespan
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --manifest-path "codespan/Cargo.toml" --no-default-features --features "serialization" --target ${{ matrix.target }}
+
   test:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        rust: ["1.46.0", "stable", "beta", "nightly"]
+        rust: ["1.67.0", "stable", "beta", "nightly"]
     name: Test Suite (${{ matrix.rust }})
     steps:
       - uses: actions/checkout@v2
@@ -95,7 +127,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        rust: ["1.46.0", "stable", "beta", "nightly"]
+        rust: ["1.67.0", "stable", "beta", "nightly"]
     name: Rustfmt (${{ matrix.rust }})
     steps:
       - uses: actions/checkout@v2

Cargo.toml

@@ -4,3 +4,4 @@ members = [
     "./codespan-reporting",
     "./codespan-lsp",
 ]
+resolver = "2"

codespan-lsp/CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-The minimum supported rustc version is now `1.46.0` (was `1.40.0`).
+The minimum supported rustc version is now `1.67.0` (was `1.40.0`).
 This is because some dependencies now require this Rust version.
 
 ### Changed

codespan-lsp/Cargo.toml

@@ -7,14 +7,28 @@ description = "Conversions between codespan types and Language Server Protocol t
 homepage = "https://github.com/brendanzab/codespan"
 repository = "https://github.com/brendanzab/codespan"
 documentation = "https://docs.rs/codespan-lsp"
-edition = "2018"
+edition = "2021"
+rust-version = "1.67"
 
 [dependencies]
-codespan-reporting = { version = "0.11.1", path = "../codespan-reporting" }
+codespan-reporting = { version = "0.11.1", path = "../codespan-reporting", features = [
+  "std",
+  "termcolor",
+] }
 # WARNING: Be extremely careful when expanding this version range.
 # We should be confident that all of the uses of `lsp-types` in `codespan-lsp`
 # will be valid for all the versions in this range. Getting this range wrong
 # could potentially break down-stream builds on a `cargo update`. This is an
 # absolute no-no, breaking much of what we enjoy about Cargo!
 lsp-types = ">=0.84, <0.92"
 url = "2"
+
+[lints.clippy]
+# Certain items from `core` are re-exported in `alloc` and `std`, and likewise `alloc` has items
+# re-exported in `std`.
+# `core` is available on all platforms, `alloc` is available on almost all, and `std` is only
+# available on some.
+# These lints ensure we don't import from a "less available" crate without reason.
+alloc_instead_of_core = "warn"
+std_instead_of_alloc = "warn"
+std_instead_of_core = "warn"

codespan-lsp/src/lib.rs

@@ -1,8 +1,12 @@
 //! Utilities for translating from codespan types into Language Server Protocol (LSP) types
 
 #![forbid(unsafe_code)]
+#![no_std]
 
-use std::ops::Range;
+#[cfg(test)]
+extern crate alloc;
+
+use core::ops::Range;
 
 use codespan_reporting::files::{Error, Files};
 
@@ -139,6 +143,8 @@ where
 
 #[cfg(test)]
 mod tests {
+    use alloc::string::ToString;
+
     use codespan_reporting::files::{Location, SimpleFiles};
 
     use super::*;

codespan-reporting/CHANGELOG.md

@@ -7,8 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-The minimum supported rustc version is now `1.46.0` (was `1.40.0`).
-This is because some testing dependencies now require this Rust version.
+The minimum supported rustc version is now `1.67.0` (was `1.40.0`).
+This is because some dependencies now require this Rust version.
 
 ### Added
 

codespan-reporting/Cargo.toml

@@ -9,11 +9,12 @@ homepage = "https://github.com/brendanzab/codespan"
 repository = "https://github.com/brendanzab/codespan"
 documentation = "https://docs.rs/codespan-reporting"
 exclude = ["assets/**"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.67"
 
 [dependencies]
-serde = { version = "1", optional = true, features = ["derive"] }
-termcolor = "1.0.4"
+serde = { version = "1", default-features = false, optional = true, features = ["derive", "alloc"] }
+termcolor = { version = "1.0.4", optional = true }
 unicode-width = ">=0.1,<0.3"
 
 [dev-dependencies]
@@ -26,5 +27,18 @@ rustyline = "6"
 unindent = "0.1"
 
 [features]
-serialization = ["serde", "serde/rc"]
+default = ["std", "termcolor"]
+std = ["serde?/std"]
+termcolor = ["std", "dep:termcolor"]
+serialization = ["serde"]
 ascii-only = []
+
+[lints.clippy]
+# Certain items from `core` are re-exported in `alloc` and `std`, and likewise `alloc` has items
+# re-exported in `std`.
+# `core` is available on all platforms, `alloc` is available on almost all, and `std` is only
+# available on some.
+# These lints ensure we don't import from a "less available" crate without reason.
+alloc_instead_of_core = "warn"
+std_instead_of_alloc = "warn"
+std_instead_of_core = "warn"

codespan-reporting/examples/custom_files.rs

@@ -12,7 +12,7 @@
 use codespan_reporting::diagnostic::{Diagnostic, Label};
 use codespan_reporting::term;
 use codespan_reporting::term::termcolor::{ColorChoice, StandardStream};
-use std::ops::Range;
+use core::ops::Range;
 
 fn main() -> anyhow::Result<()> {
     let mut files = files::Files::new();
@@ -42,7 +42,7 @@ fn main() -> anyhow::Result<()> {
 /// A module containing the file implementation
 mod files {
     use codespan_reporting::files;
-    use std::ops::Range;
+    use core::ops::Range;
 
     /// A file that is backed by an `Arc<String>`.
     #[derive(Debug, Clone)]
@@ -57,7 +57,7 @@ mod files {
 
     impl File {
         fn line_start(&self, line_index: usize) -> Result<usize, files::Error> {
-            use std::cmp::Ordering;
+            use core::cmp::Ordering;
 
             match line_index.cmp(&self.line_starts.len()) {
                 Ordering::Less => Ok(*self
@@ -95,7 +95,7 @@ mod files {
             name: impl Into<String>,
             source: impl Into<String>,
         ) -> Option<FileId> {
-            use std::convert::TryFrom;
+            use core::convert::TryFrom;
 
             let file_id = FileId(u32::try_from(self.files.len()).ok()?);
             let name = name.into();

codespan-reporting/examples/readme_preview.rs

@@ -94,6 +94,7 @@ fn main() -> anyhow::Result<()> {
             let mut buffer = Vec::new();
             let mut writer = HtmlEscapeWriter::new(SvgWriter::new(&mut buffer));
             let config = codespan_reporting::term::Config {
+                #[cfg(feature = "termcolor")]
                 styles: codespan_reporting::term::Styles::with_blue(Color::Blue),
                 ..codespan_reporting::term::Config::default()
             };
@@ -187,7 +188,7 @@ fn main() -> anyhow::Result<()> {
             )?;
         }
         Opts::Stderr { color } => {
-            let writer = StandardStream::stderr(color.into());
+            let writer = StandardStream::stderr(color);
             let config = codespan_reporting::term::Config::default();
             for diagnostic in &diagnostics {
                 term::emit(&mut writer.lock(), &config, &file, diagnostic)?;

codespan-reporting/examples/reusable_diagnostic.rs

@@ -2,7 +2,7 @@ use codespan_reporting::diagnostic::{Diagnostic, Label};
 use codespan_reporting::files::SimpleFile;
 use codespan_reporting::term::termcolor::{ColorChoice, StandardStream};
 use codespan_reporting::term::{self};
-use std::ops::Range;
+use core::ops::Range;
 
 #[derive(Debug)]
 pub struct Opts {
@@ -39,7 +39,7 @@ fn main() -> anyhow::Result<()> {
     ];
 
     let Opts { color } = parse_args()?;
-    let writer = StandardStream::stderr(color.into());
+    let writer = StandardStream::stderr(color);
     let config = codespan_reporting::term::Config::default();
     for diagnostic in errors.iter().map(Error::report) {
         term::emit(&mut writer.lock(), &config, &file, &diagnostic)?;

codespan-reporting/examples/term.rs

@@ -165,7 +165,7 @@ fn main() -> anyhow::Result<()> {
             )]),
     ];
 
-    let writer = StandardStream::stderr(color.into());
+    let writer = StandardStream::stderr(color);
     let config = codespan_reporting::term::Config::default();
     for diagnostic in &diagnostics {
         term::emit(&mut writer.lock(), &config, &files, diagnostic)?;

codespan-reporting/src/diagnostic.rs

@@ -1,9 +1,13 @@
 //! Diagnostic data structures.
 
+use alloc::{
+    string::{String, ToString},
+    vec::Vec,
+};
+use core::ops::Range;
+
 #[cfg(feature = "serialization")]
 use serde::{Deserialize, Serialize};
-use std::ops::Range;
-use std::string::ToString;
 
 /// A severity level for diagnostic messages.
 ///
@@ -188,9 +192,12 @@ impl<FileId> Diagnostic<FileId> {
         self.labels.append(&mut labels);
         self
     }
-    
+
     /// Add some labels to the diagnostic.
-    pub fn with_labels_iter(mut self, labels: impl IntoIterator<Item = Label<FileId>>) -> Diagnostic<FileId> {
+    pub fn with_labels_iter(
+        mut self,
+        labels: impl IntoIterator<Item = Label<FileId>>,
+    ) -> Diagnostic<FileId> {
         self.labels.extend(labels);
         self
     }
@@ -206,9 +213,12 @@ impl<FileId> Diagnostic<FileId> {
         self.notes.append(&mut notes);
         self
     }
-    
+
     /// Add some notes to the diagnostic.
-    pub fn with_notes_iter(mut self, notes: impl IntoIterator<Item = String>) -> Diagnostic<FileId> {
+    pub fn with_notes_iter(
+        mut self,
+        notes: impl IntoIterator<Item = String>,
+    ) -> Diagnostic<FileId> {
         self.notes.extend(notes);
         self
     }