Merge pull request #2650 from thibaultdelor/useFailureCrate

Use failure crate

7 files changed, 121 insertions, 71 deletions

diff --git a/Cargo.lock b/Cargo.lock
index fdee0b8ebe8..3d1d1cb200b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -176,6 +176,25 @@ dependencies = [
 ]
 
 [[package]]
+name = "failure"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "backtrace 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "failure_derive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "fuchsia-zircon"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -311,6 +330,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "quote"
+version = "0.3.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "quote"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
@@ -453,6 +477,7 @@ dependencies = [
  "derive-new 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "diff 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -568,6 +593,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
+version = "0.11.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "syn"
 version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
@@ -577,6 +612,23 @@ dependencies = [
 ]
 
 [[package]]
+name = "synom"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "tempdir"
 version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -655,6 +707,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "unicode-xid"
+version = "0.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "unicode-xid"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
@@ -747,6 +804,8 @@ dependencies = [
 "checksum env_logger 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)" = "00c45cec4cde3daac5f036c74098b4956151525cdf360cff5ee0092c98823e54"
 "checksum environment 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1f4b14e20978669064c33b4c1e0fb4083412e40fe56cbea2eae80fd7591503ee"
 "checksum error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ff511d5dc435d703f4971bc399647c9bc38e20cb41452e3b9feb4765419ed3f3"
+"checksum failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "934799b6c1de475a012a02dab0ace1ace43789ee4b99bcfbf1a2e3e8ced5de82"
+"checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 "checksum getopts 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)" = "b900c08c1939860ce8b54dc6a89e26e00c04c380fd0e09796799bd7f12861e05"
@@ -766,6 +825,7 @@ dependencies = [
 "checksum proc-macro2 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "b16749538926f394755373f0dfec0852d79b3bd512a5906ceaeb72ee64a4eaa0"
 "checksum pulldown-cmark 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d6fdf85cda6cadfae5428a54661d431330b312bc767ddbc57adbedc24da66e32"
 "checksum quick-error 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "eda5fe9b71976e62bc81b781206aaa076401769b2143379d3eb2118388babac4"
+"checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum quote 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9949cfe66888ffe1d53e6ec9d9f3b70714083854be20fd5e271b232a017401e8"
 "checksum rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "eba5f8cb59cc50ed56be8880a5c7b496bfd9bd26394e176bc67884094145c2c5"
 "checksum redox_syscall 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "0d92eecebad22b767915e4d529f89f28ee96dbbf5a4810d2b844373f136417fd"
@@ -792,7 +852,10 @@ dependencies = [
 "checksum skeptic 0.13.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c8431f8fca168e2db4be547bd8329eac70d095dff1444fee4b0fa0fabc7df75a"
 "checksum smallvec 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "03dab98ab5ded3a8b43b2c80751194608d0b2aa0f1d46cf95d1c35e192844aa7"
 "checksum stable_deref_trait 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "15132e0e364248108c5e2c02e3ab539be8d6f5d52a01ca9bbf27ed657316f02b"
+"checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
 "checksum syn 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)" = "91b52877572087400e83d24b9178488541e3d535259e04ff17a63df1e5ceff59"
+"checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
+"checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
 "checksum tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "15f2b5fb00ccdf689e0149d1b1b3c03fead81c2b37735d812fa8bddbbf41b6d8"
 "checksum term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "fa63644f74ce96fbeb9b794f66aff2a52d601cbd5e80f4b97123e3899f4570f1"
 "checksum term 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5e6b677dd1e8214ea1ef4297f85dbcbed8e8cdddb561040cc998ca2551c37561"
@@ -803,6 +866,7 @@ dependencies = [
 "checksum ucd-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fd2be2d6639d0f8fe6cdda291ad456e23629558d466e2789d2c3e9892bda285d"
 "checksum unicode-segmentation 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a8083c594e02b8ae1654ae26f0ade5158b119bd88ad0e8227a5d8fcd72407946"
 "checksum unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "bf3a113775714a22dcb774d8ea3655c53a32debae63a063acc00a91cc586245f"
+"checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
 "checksum utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "662fab6525a98beff2921d7f61a39e7d59e0b425ebc7d0d9e66d316e55124122"
diff --git a/Cargo.toml b/Cargo.toml
index 0924527f372..4074f67b875 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -47,6 +47,7 @@ getopts = "0.2"
 derive-new = "0.5"
 cargo_metadata = "0.5.1"
 rustc-ap-syntax = "110.0.0"
+failure = "0.1.1"
 
 [dev-dependencies]
 assert_cli = "0.5"
diff --git a/src/bin/main.rs b/src/bin/main.rs
index 453c7806d23..0ddf2f8c3df 100644
--- a/src/bin/main.rs
+++ b/src/bin/main.rs
@@ -11,6 +11,7 @@
 #![cfg(not(test))]
 
 extern crate env_logger;
+extern crate failure;
 extern crate getopts;
 extern crate rustfmt_nightly as rustfmt;
 
@@ -19,6 +20,8 @@ use std::fs::File;
 use std::io::{self, stdout, Read, Write};
 use std::path::PathBuf;
 
+use failure::err_msg;
+
 use getopts::{Matches, Options};
 
 use rustfmt::{emit_post_matter, emit_pre_matter, load_config, CliOptions, Config, FmtResult,
@@ -167,7 +170,7 @@ fn execute(opts: &Options) -> FmtResult<(WriteMode, Summary)> {
             Ok((WriteMode::None, Summary::default()))
         }
         Operation::ConfigOutputDefault { path } => {
-            let toml = Config::default().all_options().to_toml()?;
+            let toml = Config::default().all_options().to_toml().map_err(err_msg)?;
             if let Some(path) = path {
                 let mut file = File::create(path)?;
                 file.write_all(toml.as_bytes())?;
@@ -186,7 +189,9 @@ fn execute(opts: &Options) -> FmtResult<(WriteMode, Summary)> {
 
             // parse file_lines
             if let Some(ref file_lines) = matches.opt_str("file-lines") {
-                config.set().file_lines(file_lines.parse()?);
+                config
+                    .set()
+                    .file_lines(file_lines.parse().map_err(err_msg)?);
                 for f in config.file_lines().files() {
                     match *f {
                         FileName::Custom(ref f) if f == "stdin" => {}
@@ -273,7 +278,7 @@ fn format(
     // that were used during formatting as TOML.
     if let Some(path) = minimal_config_path {
         let mut file = File::create(path)?;
-        let toml = config.used_options().to_toml()?;
+        let toml = config.used_options().to_toml().map_err(err_msg)?;
         file.write_all(toml.as_bytes())?;
     }
 
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 8dde1e05c3d..23897f3cc32 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -16,8 +16,6 @@ use std::io::{Error, ErrorKind, Read};
 use std::path::{Path, PathBuf};
 use std::{env, fs};
 
-use {FmtError, FmtResult};
-
 use config::config_type::ConfigType;
 use config::file_lines::FileLines;
 pub use config::lists::*;
@@ -154,18 +152,16 @@ create_config! {
 pub fn load_config(
     file_path: Option<&Path>,
     options: Option<&CliOptions>,
-) -> FmtResult<(Config, Option<PathBuf>)> {
+) -> Result<(Config, Option<PathBuf>), Error> {
     let over_ride = match options {
         Some(opts) => config_path(opts)?,
         None => None,
     };
 
     let result = if let Some(over_ride) = over_ride {
-        Config::from_toml_path(over_ride.as_ref())
-            .map(|p| (p, Some(over_ride.to_owned())))
-            .map_err(FmtError::from)
+        Config::from_toml_path(over_ride.as_ref()).map(|p| (p, Some(over_ride.to_owned())))
     } else if let Some(file_path) = file_path {
-        Config::from_resolved_toml_path(file_path).map_err(FmtError::from)
+        Config::from_resolved_toml_path(file_path)
     } else {
         Ok((Config::default(), None))
     };
@@ -202,12 +198,15 @@ fn get_toml_path(dir: &Path) -> Result<Option<PathBuf>, Error> {
     Ok(None)
 }
 
-fn config_path(options: &CliOptions) -> FmtResult<Option<PathBuf>> {
-    let config_path_not_found = |path: &str| -> FmtResult<Option<PathBuf>> {
-        Err(FmtError::from(format!(
-            "Error: unable to find a config file for the given path: `{}`",
-            path
-        )))
+fn config_path(options: &CliOptions) -> Result<Option<PathBuf>, Error> {
+    let config_path_not_found = |path: &str| -> Result<Option<PathBuf>, Error> {
+        Err(Error::new(
+            ErrorKind::NotFound,
+            format!(
+                "Error: unable to find a config file for the given path: `{}`",
+                path
+            ),
+        ))
     };
 
     // Read the config_path and convert to parent dir if a file is provided.
diff --git a/src/config/options.rs b/src/config/options.rs
index 73dbdb88663..9721815eeee 100644
--- a/src/config/options.rs
+++ b/src/config/options.rs
@@ -14,7 +14,9 @@ use config::config_type::ConfigType;
 use config::file_lines::FileLines;
 use config::lists::*;
 use config::Config;
-use {FmtError, FmtResult, WRITE_MODE_LIST};
+use {FmtResult, WRITE_MODE_LIST};
+
+use failure::err_msg;
 
 use getopts::Matches;
 use std::collections::HashSet;
@@ -332,8 +334,8 @@ impl CliOptions {
             .map(|c| c == "nightly")
             .unwrap_or(false);
         if unstable_features && !rust_nightly {
-            return Err(FmtError::from(
-                "Unstable features are only available on Nightly channel",
+            return Err(format_err!(
+                "Unstable features are only available on Nightly channel"
             ));
         } else {
             options.unstable_features = unstable_features;
@@ -345,22 +347,23 @@ impl CliOptions {
             if let Ok(write_mode) = WriteMode::from_str(write_mode) {
                 options.write_mode = Some(write_mode);
             } else {
-                return Err(FmtError::from(format!(
+                return Err(format_err!(
                     "Invalid write-mode: {}, expected one of {}",
-                    write_mode, WRITE_MODE_LIST
-                )));
+                    write_mode,
+                    WRITE_MODE_LIST
+                ));
             }
         }
 
         if let Some(ref color) = matches.opt_str("color") {
             match Color::from_str(color) {
                 Ok(color) => options.color = Some(color),
-                _ => return Err(FmtError::from(format!("Invalid color: {}", color))),
+                _ => return Err(format_err!("Invalid color: {}", color)),
             }
         }
 
         if let Some(ref file_lines) = matches.opt_str("file-lines") {
-            options.file_lines = file_lines.parse()?;
+            options.file_lines = file_lines.parse().map_err(err_msg)?;
         }
 
         if matches.opt_present("skip-children") {
diff --git a/src/format-diff/main.rs b/src/format-diff/main.rs
index 402f7ab507a..fe528a6c0ea 100644
--- a/src/format-diff/main.rs
+++ b/src/format-diff/main.rs
@@ -15,6 +15,8 @@
 #![deny(warnings)]
 
 extern crate env_logger;
+#[macro_use]
+extern crate failure;
 extern crate getopts;
 #[macro_use]
 extern crate log;
@@ -24,9 +26,8 @@ extern crate serde_derive;
 extern crate serde_json as json;
 
 use std::collections::HashSet;
-use std::error::Error;
 use std::io::{self, BufRead};
-use std::{env, fmt, process};
+use std::{env, process};
 
 use regex::Regex;
 
@@ -35,31 +36,14 @@ use regex::Regex;
 /// We only want to format rust files by default.
 const DEFAULT_PATTERN: &str = r".*\.rs";
 
-#[derive(Debug)]
+#[derive(Fail, Debug)]
 enum FormatDiffError {
-    IncorrectOptions(getopts::Fail),
-    IncorrectFilter(regex::Error),
-    IoError(io::Error),
-}
-
-impl fmt::Display for FormatDiffError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        fmt::Display::fmt(self.cause().unwrap(), f)
-    }
-}
-
-impl Error for FormatDiffError {
-    fn description(&self) -> &str {
-        self.cause().unwrap().description()
-    }
-
-    fn cause(&self) -> Option<&Error> {
-        Some(match *self {
-            FormatDiffError::IoError(ref e) => e,
-            FormatDiffError::IncorrectFilter(ref e) => e,
-            FormatDiffError::IncorrectOptions(ref e) => e,
-        })
-    }
+    #[fail(display = "{}", _0)]
+    IncorrectOptions(#[cause] getopts::Fail),
+    #[fail(display = "{}", _0)]
+    IncorrectFilter(#[cause] regex::Error),
+    #[fail(display = "{}", _0)]
+    IoError(#[cause] io::Error),
 }
 
 impl From<getopts::Fail> for FormatDiffError {
@@ -99,7 +83,7 @@ fn main() {
     );
 
     if let Err(e) = run(&opts) {
-        println!("{}", opts.usage(e.description()));
+        println!("{}", opts.usage(&format!("{}", e)));
         process::exit(1);
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 0a5c7307e4f..b272402b20f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,6 +19,8 @@
 #[macro_use]
 extern crate derive_new;
 extern crate diff;
+#[macro_use]
+extern crate failure;
 extern crate getopts;
 extern crate itertools;
 #[cfg(test)]
@@ -37,7 +39,6 @@ extern crate toml;
 extern crate unicode_segmentation;
 
 use std::collections::HashMap;
-use std::error;
 use std::fmt;
 use std::io::{self, stdout, Write};
 use std::panic::{catch_unwind, AssertUnwindSafe};
@@ -53,6 +54,7 @@ use syntax::errors::{DiagnosticBuilder, Handler};
 use syntax::parse::{self, ParseSess};
 
 use comment::{CharClasses, FullCodeCharKind, LineClasses};
+use failure::Fail;
 use issues::{BadIssueSeeker, Issue};
 use shape::Indent;
 use utils::use_colored_tty;
@@ -62,8 +64,7 @@ pub use config::options::CliOptions;
 pub use config::summary::Summary;
 pub use config::{file_lines, load_config, Config, WriteMode};
 
-pub type FmtError = Box<error::Error + Send + Sync>;
-pub type FmtResult<T> = std::result::Result<T, FmtError>;
+pub type FmtResult<T> = std::result::Result<T, failure::Error>;
 
 pub const WRITE_MODE_LIST: &str =
     "[replace|overwrite|display|plain|diff|coverage|checkstyle|check]";
@@ -109,33 +110,26 @@ pub(crate) type FileMap = Vec<FileRecord>;
 
 pub(crate) type FileRecord = (FileName, String);
 
-#[derive(Clone, Copy)]
+#[derive(Fail, Debug, Clone, Copy)]
 pub enum ErrorKind {
     // Line has exceeded character limit (found, maximum)
+    #[fail(
+        display = "line formatted, but exceeded maximum width (maximum: {} (see `max_width` option), found: {})",
+        _0,
+        _1
+    )]
     LineOverflow(usize, usize),
     // Line ends in whitespace
+    #[fail(display = "left behind trailing whitespace")]
     TrailingWhitespace,
     // TODO or FIXME item without an issue number
+    #[fail(display = "found {}", _0)]
     BadIssue(Issue),
     // License check has failed
+    #[fail(display = "license check failed")]
     LicenseCheck,
 }
 
-impl fmt::Display for ErrorKind {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        match *self {
-            ErrorKind::LineOverflow(found, maximum) => write!(
-                fmt,
-                "line formatted, but exceeded maximum width (maximum: {} (see `max_width` option), found: {})",
-                maximum, found,
-            ),
-            ErrorKind::TrailingWhitespace => write!(fmt, "left behind trailing whitespace"),
-            ErrorKind::BadIssue(issue) => write!(fmt, "found {}", issue),
-            ErrorKind::LicenseCheck => write!(fmt, "license check failed"),
-        }
-    }
-}
-
 // Formatting errors that are identified *after* rustfmt has run.
 struct FormattingError {
     line: usize,
@@ -901,7 +895,7 @@ pub enum Input {
 
 pub fn format_and_emit_report(input: Input, config: &Config) -> FmtResult<Summary> {
     if !config.version_meets_requirement() {
-        return Err(FmtError::from("Version mismatch"));
+        return Err(format_err!("Version mismatch"));
     }
     let out = &mut stdout();
     match format_input(input, config, Some(out)) {