Auto merge of #125012 - RalfJung:format-error, r=Mark-Simulacrum,work… · rust-lang/rust@4fd98a4 (original) (raw)
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`//@ run-pass
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//@ needs-unwind
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``
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`#![feature(io_error_uncategorized)]
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``
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`use std::fmt;
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`use std::io::{self, Error, Write, sink};
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use std::panic::catch_unwind;
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``
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`struct ErrorDisplay;
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`@@ -15,7 +17,6 @@ impl fmt::Display for ErrorDisplay {
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``
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`struct ErrorWriter;
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``
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``
`-
const FORMAT_ERROR: io::ErrorKind = io::ErrorKind::Uncategorized;
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`const WRITER_ERROR: io::ErrorKind = io::ErrorKind::NotConnected;
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``
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`impl Write for ErrorWriter {
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`@@ -27,22 +28,28 @@ impl Write for ErrorWriter {
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`}
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``
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`fn main() {
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``
`-
// Test that the error from the formatter is propagated.
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``
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let res = write!(sink(), "{} {} {}", 1, ErrorDisplay, "bar");
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``
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assert!(res.is_err(), "formatter error did not propagate");
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``
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assert_eq!(res.unwrap_err().kind(), FORMAT_ERROR);
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``
-
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`// Test that an underlying error is propagated
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`let res = write!(ErrorWriter, "abc");
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`assert!(res.is_err(), "writer error did not propagate");
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``
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``
`-
// Writer error
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``
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// Test that the error from the formatter is detected.
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let res = catch_unwind(|| write!(sink(), "{} {} {}", 1, ErrorDisplay, "bar"));
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let err = res.expect_err("formatter error did not lead to panic").downcast::<&str>().unwrap();
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assert!(
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err.contains("formatting trait implementation returned an error"),
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"unexpected panic: {}", err
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);
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``
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// Writer error when there's some string before the first {}
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`let res = write!(ErrorWriter, "abc {}", ErrorDisplay);
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`assert!(res.is_err(), "writer error did not propagate");
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`assert_eq!(res.unwrap_err().kind(), WRITER_ERROR);
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``
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``
`-
// Formatter error
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``
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let res = write!(ErrorWriter, "{} abc", ErrorDisplay);
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``
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assert!(res.is_err(), "formatter error did not propagate");
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``
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assert_eq!(res.unwrap_err().kind(), FORMAT_ERROR);
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// Formatter error when the {} comes first
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``
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let res = catch_unwind(|| write!(ErrorWriter, "{} abc", ErrorDisplay));
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let err = res.expect_err("formatter error did not lead to panic").downcast::<&str>().unwrap();
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assert!(
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err.contains("formatting trait implementation returned an error"),
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"unexpected panic: {}", err
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);
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`}
`