Merge branch 'master' into bump-backtrace-rs

Author: ten3roberts

Cargo.toml

@@ -17,6 +17,7 @@ rust-version = "1.65.0"
 indenter = "0.3.0"
 once_cell = "1.18.0"
 owo-colors = "4.0"
+autocfg = "1.0"
 
 [profile.dev.package.backtrace]
 opt-level = 3

README.md

@@ -122,9 +122,12 @@ avoid using `eyre::Report` as your public error type.
   }
   ```
 
-- If using the nightly channel, a backtrace is captured and printed with the
-  error if the underlying error type does not already provide its own. In order
-  to see backtraces, they must be enabled through the environment variables
+- If using rust >1.65, a backtrace is captured and printed with the
+  error.
+
+  On nightly eyre will use the underlying error's backtrace if it has one.
+
+  In order to see backtraces, they must be enabled through the environment variables
   described in [`std::backtrace`]:
 
   - If you want panics and errors to both have backtraces, set
@@ -141,7 +144,7 @@ avoid using `eyre::Report` as your public error type.
 - Eyre works with any error type that has an impl of `std::error::Error`,
   including ones defined in your crate. We do not bundle a `derive(Error)` macro
   but you can write the impls yourself or use a standalone macro like
-  [thiserror].
+  [thiserror](https://github.com/dtolnay/thiserror).
 
   ```rust
   use thiserror::Error;
@@ -178,6 +181,15 @@ No-std support was removed in 2020 in [commit 608a16a] due to unaddressed upstre
 [commit 608a16a]:
 https://github.com/eyre-rs/eyre/pull/29/commits/608a16aa2c2c27eca6c88001cc94c6973c18f1d5
 
+
+## Backtrace support
+
+The built in default handler has support for capturing backtrace using `rustc-1.65` or later.
+
+Backtraces are captured when an error is converted to an `eyre::Report` (such as using `?` or `eyre!`).
+
+If using the nightly toolchain, backtraces will also be captured and accessed from other errors using [error_generic_member_access](https://github.com/rust-lang/rfcs/pull/2895) if available.
+
 ## Comparison to failure
 
 The `eyre::Report` type works something like `failure::Error`, but unlike
@@ -195,8 +207,6 @@ you need an error type that can be handled via match or reported. This is
 common in library crates where you don't know how your users will handle
 your errors.
 
-[thiserror]: https://github.com/dtolnay/thiserror
-
 ## Compatibility with `anyhow`
 
 This crate does its best to be usable as a drop in replacement of `anyhow` and

color-eyre/src/config.rs

@@ -11,39 +11,6 @@ use std::env;
 use std::fmt::Write as _;
 use std::{fmt, path::PathBuf, sync::Arc};
 
-#[derive(Debug)]
-struct InstallError;
-
-impl fmt::Display for InstallError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str("could not install the BacktracePrinter as another was already installed")
-    }
-}
-
-impl std::error::Error for InstallError {}
-
-#[derive(Debug)]
-struct InstallThemeError;
-
-impl fmt::Display for InstallThemeError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str("could not set the provided `Theme` globally as another was already set")
-    }
-}
-
-impl std::error::Error for InstallThemeError {}
-
-#[derive(Debug)]
-struct InstallColorSpantraceThemeError;
-
-impl fmt::Display for InstallColorSpantraceThemeError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str("could not set the provided `Theme` via `color_spantrace::set_theme` globally as another was already set")
-    }
-}
-
-impl std::error::Error for InstallColorSpantraceThemeError {}
-
 /// A struct that represents a theme that is used by `color_eyre`
 #[derive(Debug, Copy, Clone, Default)]
 pub struct Theme {

color-eyre/src/writers.rs

@@ -28,11 +28,13 @@ impl<W> WriterExt for W {
     }
 }
 
+#[cfg(feature = "issue-url")]
 pub(crate) trait DisplayExt: Sized + Display {
     fn with_header<H: Display>(self, header: H) -> Header<Self, H>;
     fn with_footer<F: Display>(self, footer: F) -> Footer<Self, F>;
 }
 
+#[cfg(feature = "issue-url")]
 impl<T> DisplayExt for T
 where
     T: Display,
@@ -80,11 +82,13 @@ where
     }
 }
 
+#[cfg(feature = "issue-url")]
 pub(crate) struct FooterWriter<W> {
     inner: W,
     had_output: bool,
 }
 
+#[cfg(feature = "issue-url")]
 impl<W> fmt::Write for FooterWriter<W>
 where
     W: fmt::Write,
@@ -98,6 +102,7 @@ where
     }
 }
 
+#[cfg(feature = "issue-url")]
 #[allow(explicit_outlives_requirements)]
 pub(crate) struct Footer<B, H>
 where
@@ -108,6 +113,7 @@ where
     footer: H,
 }
 
+#[cfg(feature = "issue-url")]
 impl<B, H> fmt::Display for Footer<B, H>
 where
     B: Display,
@@ -129,6 +135,7 @@ where
     }
 }
 
+#[cfg(feature = "issue-url")]
 #[allow(explicit_outlives_requirements)]
 pub(crate) struct Header<B, H>
 where
@@ -139,6 +146,7 @@ where
     h: H,
 }
 
+#[cfg(feature = "issue-url")]
 impl<B, H> fmt::Display for Header<B, H>
 where
     B: Display,

color-eyre/tests/theme.rs

@@ -170,7 +170,12 @@ fn test_backwards_compatibility(target: String, file_name: &str) {
     fn normalize_backtrace(input: &str) -> String {
         input
             .lines()
-            .take_while(|v| !v.contains("core::panic") && !v.contains("theme_test_helper::main"))
+            .take_while(|v| {
+                !v.contains("core::panic")
+                    && !v.contains("theme_test_helper::main")
+                    && !v.contains("theme::test_error_backwards_compatibility::closure")
+                    && !v.contains("theme::test_error_backwards_compatibility::{{closure}}")
+            })
             .collect::<Vec<_>>()
             .join("\n")
     }

eyre/Cargo.toml

@@ -23,6 +23,9 @@ indenter = { workspace = true }
 once_cell = { workspace = true }
 pyo3 = { version = "0.20", optional = true, default-features = false }
 
+[build-dependencies]
+autocfg = { workspace = true }
+
 [dev-dependencies]
 futures = { version = "0.3", default-features = false }
 rustversion = "1.0"

eyre/build.rs

@@ -1,23 +1,53 @@
-use std::env;
-use std::ffi::OsString;
-use std::fs;
-use std::path::Path;
-use std::process::{Command, ExitStatus};
-use std::str;
-
-// This code exercises the surface area that we expect of the std Backtrace
-// type. If the current toolchain is able to compile it, we go ahead and use
-// backtrace in eyre.
-const BACKTRACE_PROBE: &str = r#"
-    #![feature(backtrace)]
+use std::{
+    env, fs,
+    path::Path,
+    process::{Command, ExitStatus},
+};
+
+fn main() {
+    let ac = autocfg::new();
+
+    // https://github.com/rust-lang/rust/issues/99301 [nightly]
+    //
+    // Autocfg does currently not support custom probes, or `nightly` only features
+    match compile_probe(GENERIC_MEMBER_ACCESS_PROBE) {
+        Some(status) if status.success() => autocfg::emit("generic_member_access"),
+        _ => {}
+    }
+
+    // https://github.com/rust-lang/rust/issues/47809 [rustc-1.46]
+    ac.emit_expression_cfg("std::panic::Location::caller", "track_caller");
+
+    if ac.probe_rustc_version(1, 52) {
+        autocfg::emit("eyre_no_fmt_arguments_as_str");
+    }
+
+    if ac.probe_rustc_version(1, 58) {
+        autocfg::emit("eyre_no_fmt_args_capture");
+    }
+
+    if ac.probe_rustc_version(1, 65) {
+        autocfg::emit("backtrace")
+    }
+}
+
+// This code exercises the surface area or the generic member access feature for the `std::error::Error` trait.
+//
+// This is use to detect and supply backtrace information through different errors types.
+const GENERIC_MEMBER_ACCESS_PROBE: &str = r#"
+    #![feature(error_generic_member_access)]
     #![allow(dead_code)]
 
-    use std::backtrace::{Backtrace, BacktraceStatus};
-    use std::error::Error;
+    use std::error::{Error, Request};
     use std::fmt::{self, Display};
 
     #[derive(Debug)]
-    struct E;
+    struct E { 
+        backtrace: MyBacktrace,
+    }
+
+    #[derive(Debug)]
+    struct MyBacktrace;
 
     impl Display for E {
         fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
@@ -26,59 +56,44 @@ const BACKTRACE_PROBE: &str = r#"
     }
 
     impl Error for E {
-        fn backtrace(&self) -> Option<&Backtrace> {
-            let backtrace = Backtrace::capture();
-            match backtrace.status() {
-                BacktraceStatus::Captured | BacktraceStatus::Disabled | _ => {}
-            }
-            unimplemented!()
+        fn provide<'a>(&'a self, request: &mut Request<'a>) {
+            request
+                .provide_ref::<MyBacktrace>(&self.backtrace);
         }
     }
 "#;
 
-const TRACK_CALLER_PROBE: &str = r#"
-    #![allow(dead_code)]
-
-    #[track_caller]
-    fn foo() {
-        let _location = std::panic::Location::caller();
-    }
-"#;
-
-fn main() {
-    match compile_probe(BACKTRACE_PROBE) {
-        Some(status) if status.success() => println!("cargo:rustc-cfg=backtrace"),
-        _ => {}
-    }
-
-    match compile_probe(TRACK_CALLER_PROBE) {
-        Some(status) if status.success() => println!("cargo:rustc-cfg=track_caller"),
-        _ => {}
-    }
+fn compile_probe(probe: &str) -> Option<ExitStatus> {
+    let rustc = env::var_os("RUSTC")?;
+    let out_dir = env::var_os("OUT_DIR")?;
+    let probefile = Path::new(&out_dir).join("probe.rs");
+    fs::write(&probefile, probe).ok()?;
 
-    let version = match rustc_version_info() {
-        Some(version) => version,
-        None => return,
-    };
+    let rustc_wrapper = env::var_os("RUSTC_WRAPPER").filter(|wrapper| !wrapper.is_empty());
+    let rustc_workspace_wrapper =
+        env::var_os("RUSTC_WORKSPACE_WRAPPER").filter(|wrapper| !wrapper.is_empty());
+    let mut rustc = rustc_wrapper
+        .into_iter()
+        .chain(rustc_workspace_wrapper)
+        .chain(std::iter::once(rustc));
 
-    version.toolchain.set_feature();
+    let mut cmd = Command::new(rustc.next().unwrap());
+    cmd.args(rustc);
 
-    if version.minor < 52 {
-        println!("cargo:rustc-cfg=eyre_no_fmt_arguments_as_str");
+    if let Some(target) = env::var_os("TARGET") {
+        cmd.arg("--target").arg(target);
     }
 
-    if version.minor < 58 {
-        println!("cargo:rustc-cfg=eyre_no_fmt_args_capture");
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = env::var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
     }
-}
 
-fn compile_probe(probe: &str) -> Option<ExitStatus> {
-    let rustc = env::var_os("RUSTC")?;
-    let out_dir = env::var_os("OUT_DIR")?;
-    let probefile = Path::new(&out_dir).join("probe.rs");
-    fs::write(&probefile, probe).ok()?;
-    Command::new(rustc)
-        .arg("--edition=2018")
+    cmd.arg("--edition=2018")
         .arg("--crate-name=eyre_build")
         .arg("--crate-type=lib")
         .arg("--emit=metadata")
@@ -88,45 +103,3 @@ fn compile_probe(probe: &str) -> Option<ExitStatus> {
         .status()
         .ok()
 }
-
-// TODO factor this toolchain parsing and related tests into its own file
-#[derive(PartialEq)]
-enum Toolchain {
-    Stable,
-    Beta,
-    Nightly,
-}
-impl Toolchain {
-    fn set_feature(self) {
-        match self {
-            Toolchain::Nightly => println!("cargo:rustc-cfg=nightly"),
-            Toolchain::Beta => println!("cargo:rustc-cfg=beta"),
-            Toolchain::Stable => println!("cargo:rustc-cfg=stable"),
-        }
-    }
-}
-
-struct VersionInfo {
-    minor: u32,
-    toolchain: Toolchain,
-}
-
-fn rustc_version_info() -> Option<VersionInfo> {
-    let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
-    let output = Command::new(rustc).arg("--version").output().ok()?;
-    let version = str::from_utf8(&output.stdout).ok()?;
-    let mut pieces = version.split(['.', ' ', '-']);
-    if pieces.next() != Some("rustc") {
-        return None;
-    }
-    let _major: u32 = pieces.next()?.parse().ok()?;
-    let minor = pieces.next()?.parse().ok()?;
-    let _patch: u32 = pieces.next()?.parse().ok()?;
-    let toolchain = match pieces.next() {
-        Some("beta") => Toolchain::Beta,
-        Some("nightly") => Toolchain::Nightly,
-        _ => Toolchain::Stable,
-    };
-    let version = VersionInfo { minor, toolchain };
-    Some(version)
-}