feat: no-std support

.github/workflows/ci.yml

@@ -68,6 +68,21 @@ jobs:
       - name: Check wasm target
         run: cargo check --target wasm32-unknown-unknown --features fancy-no-syscall
 
+  no-std:
+    name: Check no-std build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+          targets: wasm32-unknown-unknown
+      - name: Check no-std core build
+        run: cargo check --target wasm32-unknown-unknown --no-default-features
+      - name: Check no-std with fancy-no-syscall
+        run: cargo check --target wasm32-unknown-unknown --no-default-features --features fancy-no-syscall
+
   miri:
     name: Miri
     runs-on: ubuntu-latest

Cargo.toml

@@ -13,9 +13,11 @@ rust-version = "1.82.0"
 exclude = ["images/", "tests/", "miette-derive/"]
 
 [dependencies]
+thiserror = "2.0.11"
 miette-derive = { path = "miette-derive", version = "=7.6.0", optional = true }
-unicode-width = "0.2.0"
+unicode-width = { version = "0.2.0", default-features = false }
 cfg-if = "1.0.0"
+spin = { version = "0.9", default-features = false, features = ["mutex", "spin_mutex", "lazy"] }
 
 owo-colors = { version = "4.0.0", optional = true }
 textwrap = { version = "0.16.0", default-features = false, features = ["unicode-linebreak", "unicode-width"], optional = true }
@@ -29,23 +31,23 @@ serde = { version = "1.0.196", features = ["derive"], optional = true }
 syntect = { version = "5.1.0", optional = true }
 
 [dev-dependencies]
-thiserror = "2.0.11"
 semver = "1.0.21"
-
-# Eyre devdeps
 futures = { version = "0.3", default-features = false }
 indenter = "0.3.3"
 rustversion = "1.0"
 trybuild = { version = "1.0.89", features = ["diff"] }
 syn = { version = "2.0.87", features = ["full"] }
 regex = "1.10"
-
 serde = { version = "1.0.196", features = ["derive"] }
 serde_json = "1.0.113"
 strip-ansi-escapes = "0.2.0"
 
+[build-dependencies]
+rustc_version = "0.2"
+
 [features]
-default = ["derive"]
+default = ["derive", "std"]
+std = ["thiserror/std", "fancy-no-syscall"]
 derive = ["dep:miette-derive"]
 no-format-args-capture = []
 fancy-base = [
@@ -63,7 +65,7 @@ fancy-no-backtrace = [
     "dep:supports-unicode",
 ]
 fancy = ["fancy-no-backtrace", "dep:backtrace", "dep:backtrace-ext"]
-syntect-highlighter = ["fancy-no-backtrace", "dep:syntect"]
+syntect-highlighter = ["fancy-no-backtrace", "dep:syntect", "std"]
 
 [workspace]
 members = ["miette-derive"]

README.md

@@ -58,8 +58,8 @@ diagnostic error code: ruget::api::bad_json
 
 ### Features
 
-- Generic [`Diagnostic`] protocol, compatible (and dependent on)
-  [`std::error::Error`].
+- Generic [`Diagnostic`] protocol, compatible with `std::error::Error`.
+  Works without the standard library: Just turn off the default `std` feature and you can use `miette` in places like embedded systems or web browsers that don't have the full standard library. You still need `alloc` for memory management.
 - Unique error codes on every [`Diagnostic`].
 - Custom links to get more details on error codes.
 - Super handy derive macro for defining diagnostic metadata.
@@ -93,6 +93,19 @@ If you want to use the fancy printer in all these screenshots:
 $ cargo add miette --features fancy
 ```
 
+For computers without the standard library (like microcontrollers or web browsers):
+
+```sh
+$ cargo add miette --no-default-features --features derive
+```
+
+Available features you can turn on or off:
+- `std` (on by default): Use the standard library
+- `derive`: Lets you automatically create error types
+- `fancy`: Shows pretty error messages with colors
+- `fancy-no-syscall`: Pretty errors without using system calls
+- `fancy-no-backtrace`: Pretty errors without showing the call stack
+
 ### Example
 
 ```rust

build.rs

@@ -0,0 +1,15 @@
+use rustc_version::{version_meta, Channel};
+
+fn main() {
+    if let Channel::Nightly = version_meta().unwrap().channel {
+        println!("cargo:rustc-cfg=nightly")
+    }
+
+    // track_caller is stable since Rust 1.46 (2020), so no version check needed
+    println!("cargo:rustc-cfg=track_caller");
+
+    // Add check-cfg for conditional configurations
+    println!("cargo:rustc-check-cfg=cfg(doc_cfg)");
+    println!("cargo:rustc-check-cfg=cfg(track_caller)");
+    println!("cargo:rustc-check-cfg=cfg(nightly)");
+}

examples/serde_json.rs

@@ -2,6 +2,8 @@
 //! so the decoding source will be annotated with the decoding error,
 //! providing contextual information about the error.
 
+extern crate alloc;
+
 use miette::{IntoDiagnostic, SourceOffset};
 use serde_json::{self, json};
 

miette-derive/src/code.rs

@@ -56,13 +56,13 @@ impl Code {
                 let code = &code.as_ref()?.0;
                 Some(match fields {
                     syn::Fields::Named(_) => {
-                        quote! { Self::#ident { .. } => std::option::Option::Some(std::boxed::Box::new(#code)), }
+                        quote! { Self::#ident { .. } => core::option::Option::Some(alloc::boxed::Box::new(#code)), }
                     }
                     syn::Fields::Unnamed(_) => {
-                        quote! { Self::#ident(..) => std::option::Option::Some(std::boxed::Box::new(#code)), }
+                        quote! { Self::#ident(..) => core::option::Option::Some(alloc::boxed::Box::new(#code)), }
                     }
                     syn::Fields::Unit => {
-                        quote! { Self::#ident => std::option::Option::Some(std::boxed::Box::new(#code)), }
+                        quote! { Self::#ident => core::option::Option::Some(alloc::boxed::Box::new(#code)), }
                     }
                 })
             },
@@ -72,8 +72,8 @@ impl Code {
     pub(crate) fn gen_struct(&self) -> Option<TokenStream> {
         let code = &self.0;
         Some(quote! {
-            fn code(&self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>> {
-                std::option::Option::Some(std::boxed::Box::new(#code))
+            fn code(&self) -> core::option::Option<alloc::boxed::Box<dyn core::fmt::Display + '_>> {
+                core::option::Option::Some(alloc::boxed::Box::new(#code))
             }
         })
     }

miette-derive/src/diagnostic_source.rs

@@ -59,7 +59,7 @@ impl DiagnosticSource {
                     };
                     quote! {
                         Self::#ident #display_pat => {
-                            std::option::Option::Some(std::borrow::Borrow::borrow(#rel))
+                            core::option::Option::Some(alloc::borrow::Borrow::borrow(#rel))
                         }
                     }
                 })
@@ -70,8 +70,8 @@ impl DiagnosticSource {
     pub(crate) fn gen_struct(&self) -> Option<TokenStream> {
         let rel = &self.0;
         Some(quote! {
-            fn diagnostic_source<'a>(&'a self) -> std::option::Option<&'a dyn miette::Diagnostic> {
-                std::option::Option::Some(std::borrow::Borrow::borrow(&self.#rel))
+            fn diagnostic_source<'a>(&'a self) -> core::option::Option<&'a dyn miette::Diagnostic> {
+                core::option::Option::Some(alloc::borrow::Borrow::borrow(&self.#rel))
             }
         })
     }

miette-derive/src/forward.rs

@@ -58,34 +58,34 @@ impl WhichFn {
     pub fn signature(&self) -> TokenStream {
         match self {
             Self::Code => quote! {
-                fn code(& self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>>
+                fn code(& self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>>
             },
             Self::Help => quote! {
-                fn help(& self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>>
+                fn help(& self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>>
             },
             Self::Url => quote! {
-                fn url(& self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>>
+                fn url(& self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>>
             },
             Self::Severity => quote! {
-                fn severity(&self) -> std::option::Option<miette::Severity>
+                fn severity(&self) -> Option<miette::Severity>
             },
             Self::Related => quote! {
-                fn related(&self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = &dyn miette::Diagnostic> + '_>>
+                fn related(&self) -> Option<alloc::boxed::Box<dyn Iterator<Item = &dyn miette::Diagnostic> + '_>>
             },
             Self::Labels => quote! {
-                fn labels(&self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = miette::LabeledSpan> + '_>>
+                fn labels(&self) -> Option<alloc::boxed::Box<dyn Iterator<Item = miette::LabeledSpan> + '_>>
             },
             Self::SourceCode => quote! {
-                fn source_code(&self) -> std::option::Option<&dyn miette::SourceCode>
+                fn source_code(&self) -> Option<&dyn miette::SourceCode>
             },
             Self::DiagnosticSource => quote! {
-                fn diagnostic_source(&self) -> std::option::Option<&dyn miette::Diagnostic>
+                fn diagnostic_source(&self) -> Option<&dyn miette::Diagnostic>
             },
         }
     }
 
     pub fn catchall_arm(&self) -> TokenStream {
-        quote! { _ => std::option::Option::None }
+        quote! { _ => Option::None }
     }
 }
 

miette-derive/src/help.rs

@@ -94,7 +94,7 @@ impl Help {
                     Help::Display(display) => {
                         let (fmt, args) = display.expand_shorthand_cloned(&display_members);
                         Some(quote! {
-                            Self::#ident #display_pat => std::option::Option::Some(std::boxed::Box::new(format!(#fmt #args))),
+                            Self::#ident #display_pat => Option::Some(alloc::boxed::Box::new(format!(#fmt #args))),
                         })
                     }
                     Help::Field(member, ty) => {
@@ -108,7 +108,7 @@ impl Help {
                         Some(quote! {
                             Self::#ident #display_pat => {
                                 use miette::macro_helpers::ToOption;
-                                miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&#help).as_ref().map(|#var| -> std::boxed::Box<dyn std::fmt::Display + '_> { std::boxed::Box::new(format!("{}", #var)) })
+                                miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&#help).as_ref().map(|#var| -> alloc::boxed::Box<dyn core::fmt::Display + '_> { alloc::boxed::Box::new(format!("{}", #var)) })
                             },
                         })
                     }
@@ -123,21 +123,21 @@ impl Help {
             Help::Display(display) => {
                 let (fmt, args) = display.expand_shorthand_cloned(&display_members);
                 Some(quote! {
-                    fn help(&self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>> {
+                    fn help(&self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>> {
                         #[allow(unused_variables, deprecated)]
                         let Self #display_pat = self;
-                        std::option::Option::Some(std::boxed::Box::new(format!(#fmt #args)))
+                        Option::Some(alloc::boxed::Box::new(format!(#fmt #args)))
                     }
                 })
             }
             Help::Field(member, ty) => {
                 let var = quote! { __miette_internal_var };
                 Some(quote! {
-                    fn help(&self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>> {
+                    fn help(&self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>> {
                         #[allow(unused_variables, deprecated)]
                         let Self #display_pat = self;
                         use miette::macro_helpers::ToOption;
-                        miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#member).as_ref().map(|#var| -> std::boxed::Box<dyn std::fmt::Display + '_> { std::boxed::Box::new(format!("{}", #var)) })
+                        miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#member).as_ref().map(|#var| -> alloc::boxed::Box<dyn core::fmt::Display + '_> { alloc::boxed::Box::new(format!("{}", #var)) })
                     }
                 })
             }

miette-derive/src/label.rs

@@ -175,9 +175,9 @@ impl Labels {
             let var = quote! { __miette_internal_var };
             let display = if let Some(display) = label {
                 let (fmt, args) = display.expand_shorthand_cloned(&display_members);
-                quote! { std::option::Option::Some(format!(#fmt #args)) }
+                quote! { Option::Some(format!(#fmt #args)) }
             } else {
-                quote! { std::option::Option::None }
+                quote! { Option::None }
             };
             let ctor = if *lbl_ty == LabelType::Primary {
                 quote! { miette::LabeledSpan::new_primary_with_span }
@@ -205,9 +205,9 @@ impl Labels {
             }
             let display = if let Some(display) = label {
                 let (fmt, args) = display.expand_shorthand_cloned(&display_members);
-                quote! { std::option::Option::Some(format!(#fmt #args)) }
+                quote! { Option::Some(format!(#fmt #args)) }
             } else {
-                quote! { std::option::Option::None }
+                quote! { Option::None }
             };
             Some(quote! {
                 .chain({
@@ -226,7 +226,7 @@ impl Labels {
 
         Some(quote! {
             #[allow(unused_variables)]
-            fn labels(&self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = miette::LabeledSpan> + '_>> {
+            fn labels(&self) -> Option<alloc::boxed::Box<dyn Iterator<Item = miette::LabeledSpan> + '_>> {
                 use miette::macro_helpers::ToOption;
                 let Self #display_pat = self;
 
@@ -236,7 +236,7 @@ impl Labels {
                 .into_iter()
                 #(#collections_chain)*;
 
-                std::option::Option::Some(Box::new(labels_iter.filter(Option::is_some).map(Option::unwrap)))
+                Option::Some(alloc::boxed::Box::new(labels_iter.filter(Option::is_some).map(Option::unwrap)))
             }
         })
     }
@@ -322,7 +322,7 @@ impl Labels {
                                 ]
                                 .into_iter()
                                 #(#collections_chain)*;
-                                std::option::Option::Some(std::boxed::Box::new(labels_iter.filter(Option::is_some).map(Option::unwrap)))
+                                Option::Some(alloc::boxed::Box::new(labels_iter.filter(Option::is_some).map(Option::unwrap)))
                             }
                         }),
                     }

miette-derive/src/related.rs

@@ -55,7 +55,7 @@ impl Related {
                     };
                     quote! {
                         Self::#ident #display_pat => {
-                            std::option::Option::Some(std::boxed::Box::new(
+                            Option::Some(alloc::boxed::Box::new(
                                 #rel.iter().map(|x| -> &(dyn miette::Diagnostic) { &*x })
                             ))
                         }
@@ -68,9 +68,9 @@ impl Related {
     pub(crate) fn gen_struct(&self) -> Option<TokenStream> {
         let rel = &self.0;
         Some(quote! {
-            fn related<'a>(&'a self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = &'a dyn miette::Diagnostic> + 'a>> {
-                use ::core::borrow::Borrow;
-                std::option::Option::Some(std::boxed::Box::new(
+            fn related<'a>(&'a self) -> Option<alloc::boxed::Box<dyn Iterator<Item = &'a dyn miette::Diagnostic> + 'a>> {
+                use alloc::borrow::Borrow;
+                Option::Some(alloc::boxed::Box::new(
                         self.#rel.iter().map(|x| -> &(dyn miette::Diagnostic) { &*x.borrow() })
                 ))
             }

miette-derive/src/severity.rs

@@ -71,9 +71,7 @@ impl Severity {
                     syn::Fields::Unnamed(_) => quote! { (..) },
                     syn::Fields::Unit => quote! {},
                 };
-                Some(
-                    quote! { Self::#ident #fields => std::option::Option::Some(miette::Severity::#severity), },
-                )
+                Some(quote! { Self::#ident #fields => Option::Some(miette::Severity::#severity), })
             },
         )
     }

miette-derive/src/source_code.rs

@@ -74,7 +74,7 @@ impl SourceCode {
 
         Some(quote! {
             #[allow(unused_variables)]
-            fn source_code(&self) -> std::option::Option<&dyn miette::SourceCode> {
+            fn source_code(&self) -> Option<&dyn miette::SourceCode> {
                 let Self #display_pat = self;
                 #ret
             }
@@ -101,7 +101,7 @@ impl SourceCode {
                         }
                     } else {
                         quote! {
-                            std::option::Option::Some(#field)
+                            Option::Some(#field)
                         }
                     };
                     match &fields {

miette-derive/src/url.rs

@@ -96,7 +96,7 @@ impl Url {
                     }
                 };
                 Some(quote! {
-                    Self::#ident #pat => std::option::Option::Some(std::boxed::Box::new(format!(#fmt #args))),
+                    Self::#ident #pat => Option::Some(alloc::boxed::Box::new(format!(#fmt #args))),
                 })
             },
         )
@@ -129,10 +129,10 @@ impl Url {
             }
         };
         Some(quote! {
-            fn url(&self) -> std::option::Option<std::boxed::Box<dyn std::fmt::Display + '_>> {
+            fn url(&self) -> Option<alloc::boxed::Box<dyn core::fmt::Display + '_>> {
                 #[allow(unused_variables, deprecated)]
                 let Self #pat = self;
-                std::option::Option::Some(std::boxed::Box::new(format!(#fmt #args)))
+                Option::Some(alloc::boxed::Box::new(format!(#fmt #args)))
             }
         })
     }