chore: add vendor dependencies for kauma build

vendor/anyhow/tests/test_context.rs

@@ -0,0 +1,172 @@
+#![allow(
+    // Clippy bug: https://github.com/rust-lang/rust-clippy/issues/7422
+    clippy::nonstandard_macro_braces,
+)]
+
+mod drop;
+
+use crate::drop::{DetectDrop, Flag};
+use anyhow::{Context, Error, Result};
+use std::fmt::{self, Display};
+use thiserror::Error;
+
+// https://github.com/dtolnay/anyhow/issues/18
+#[test]
+fn test_inference() -> Result<()> {
+    let x = "1";
+    let y: u32 = x.parse().context("...")?;
+    assert_eq!(y, 1);
+    Ok(())
+}
+
+macro_rules! context_type {
+    ($name:ident) => {
+        #[derive(Debug)]
+        struct $name {
+            message: &'static str,
+            #[allow(dead_code)]
+            drop: DetectDrop,
+        }
+
+        impl Display for $name {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.write_str(self.message)
+            }
+        }
+    };
+}
+
+context_type!(HighLevel);
+context_type!(MidLevel);
+
+#[derive(Error, Debug)]
+#[error("{message}")]
+struct LowLevel {
+    message: &'static str,
+    drop: DetectDrop,
+}
+
+struct Dropped {
+    low: Flag,
+    mid: Flag,
+    high: Flag,
+}
+
+impl Dropped {
+    fn none(&self) -> bool {
+        !self.low.get() && !self.mid.get() && !self.high.get()
+    }
+
+    fn all(&self) -> bool {
+        self.low.get() && self.mid.get() && self.high.get()
+    }
+}
+
+fn make_chain() -> (Error, Dropped) {
+    let dropped = Dropped {
+        low: Flag::new(),
+        mid: Flag::new(),
+        high: Flag::new(),
+    };
+
+    let low = LowLevel {
+        message: "no such file or directory",
+        drop: DetectDrop::new(&dropped.low),
+    };
+
+    // impl Context for Result<T, E>
+    let mid = Err::<(), LowLevel>(low)
+        .context(MidLevel {
+            message: "failed to load config",
+            drop: DetectDrop::new(&dropped.mid),
+        })
+        .unwrap_err();
+
+    // impl Context for Result<T, Error>
+    let high = Err::<(), Error>(mid)
+        .context(HighLevel {
+            message: "failed to start server",
+            drop: DetectDrop::new(&dropped.high),
+        })
+        .unwrap_err();
+
+    (high, dropped)
+}
+
+#[test]
+fn test_downcast_ref() {
+    let (err, dropped) = make_chain();
+
+    assert!(!err.is::<String>());
+    assert!(err.downcast_ref::<String>().is_none());
+
+    assert!(err.is::<HighLevel>());
+    let high = err.downcast_ref::<HighLevel>().unwrap();
+    assert_eq!(high.to_string(), "failed to start server");
+
+    assert!(err.is::<MidLevel>());
+    let mid = err.downcast_ref::<MidLevel>().unwrap();
+    assert_eq!(mid.to_string(), "failed to load config");
+
+    assert!(err.is::<LowLevel>());
+    let low = err.downcast_ref::<LowLevel>().unwrap();
+    assert_eq!(low.to_string(), "no such file or directory");
+
+    assert!(dropped.none());
+    drop(err);
+    assert!(dropped.all());
+}
+
+#[test]
+fn test_downcast_high() {
+    let (err, dropped) = make_chain();
+
+    let err = err.downcast::<HighLevel>().unwrap();
+    assert!(!dropped.high.get());
+    assert!(dropped.low.get() && dropped.mid.get());
+
+    drop(err);
+    assert!(dropped.all());
+}
+
+#[test]
+fn test_downcast_mid() {
+    let (err, dropped) = make_chain();
+
+    let err = err.downcast::<MidLevel>().unwrap();
+    assert!(!dropped.mid.get());
+    assert!(dropped.low.get() && dropped.high.get());
+
+    drop(err);
+    assert!(dropped.all());
+}
+
+#[test]
+fn test_downcast_low() {
+    let (err, dropped) = make_chain();
+
+    let err = err.downcast::<LowLevel>().unwrap();
+    assert!(!dropped.low.get());
+    assert!(dropped.mid.get() && dropped.high.get());
+
+    drop(err);
+    assert!(dropped.all());
+}
+
+#[test]
+fn test_unsuccessful_downcast() {
+    let (err, dropped) = make_chain();
+
+    let err = err.downcast::<String>().unwrap_err();
+    assert!(dropped.none());
+
+    drop(err);
+    assert!(dropped.all());
+}
+
+#[test]
+fn test_root_cause() {
+    let (err, _) = make_chain();
+
+    assert_eq!(err.root_cause().to_string(), "no such file or directory");
+}