Rationalise error types

cc #2639

Author: nrc

src/bin/main.rs

@@ -26,7 +26,7 @@ use getopts::{Matches, Options};
 
 use rustfmt::{
     emit_post_matter, emit_pre_matter, format_and_emit_report, load_config, CliOptions, Config,
-    FileName, FmtResult, Input, Summary, Verbosity, WriteMode,
+    ErrorKind, FileName, Input, Summary, Verbosity, WriteMode,
 };
 
 fn main() {
@@ -170,7 +170,7 @@ fn is_nightly() -> bool {
         .unwrap_or(false)
 }
 
-fn execute(opts: &Options) -> FmtResult<(WriteMode, Summary)> {
+fn execute(opts: &Options) -> Result<(WriteMode, Summary), failure::Error> {
     let matches = opts.parse(env::args().skip(1))?;
     let options = CliOptions::from_matches(&matches)?;
 
@@ -239,7 +239,7 @@ fn format(
     files: Vec<PathBuf>,
     minimal_config_path: Option<String>,
     options: CliOptions,
-) -> FmtResult<(WriteMode, Summary)> {
+) -> Result<(WriteMode, Summary), failure::Error> {
     options.verify_file_lines(&files);
     let (config, config_path) = load_config(None, Some(&options))?;
 
@@ -347,7 +347,7 @@ fn print_version() {
     println!("rustfmt {}", version_info);
 }
 
-fn determine_operation(matches: &Matches) -> FmtResult<Operation> {
+fn determine_operation(matches: &Matches) -> Result<Operation, ErrorKind> {
     if matches.opt_present("h") {
         let topic = matches.opt_str("h");
         if topic == None {

src/config/options.rs

@@ -14,9 +14,8 @@ use config::config_type::ConfigType;
 use config::file_lines::FileLines;
 use config::lists::*;
 use config::Config;
-use FmtResult;
 
-use failure::err_msg;
+use failure::{self, err_msg};
 
 use getopts::Matches;
 use std::collections::HashSet;
@@ -345,7 +344,7 @@ pub struct CliOptions {
 }
 
 impl CliOptions {
-    pub fn from_matches(matches: &Matches) -> FmtResult<CliOptions> {
+    pub fn from_matches(matches: &Matches) -> Result<CliOptions, failure::Error> {
         let mut options = CliOptions::default();
         options.verbose = matches.opt_present("verbose");
         options.quiet = matches.opt_present("quiet");
@@ -448,7 +447,7 @@ impl CliOptions {
     }
 }
 
-fn write_mode_from_emit_str(emit_str: &str) -> FmtResult<WriteMode> {
+fn write_mode_from_emit_str(emit_str: &str) -> Result<WriteMode, failure::Error> {
     match emit_str {
         "files" => Ok(WriteMode::Overwrite),
         "stdout" => Ok(WriteMode::Display),

src/lib.rs

@@ -64,8 +64,6 @@ pub use config::options::CliOptions;
 pub use config::summary::Summary;
 pub use config::{file_lines, load_config, Config, Verbosity, WriteMode};
 
-pub type FmtResult<T> = std::result::Result<T, failure::Error>;
-
 #[macro_use]
 mod utils;
 
@@ -107,7 +105,7 @@ pub(crate) type FileMap = Vec<FileRecord>;
 
 pub(crate) type FileRecord = (FileName, String);
 
-#[derive(Fail, Debug, Clone, Copy)]
+#[derive(Fail, Debug)]
 pub enum ErrorKind {
     // Line has exceeded character limit (found, maximum)
     #[fail(
@@ -132,6 +130,14 @@ pub enum ErrorKind {
     // Used a rustfmt:: attribute other than skip
     #[fail(display = "invalid attribute")]
     BadAttr,
+    #[fail(display = "io error: {}", _0)]
+    IoError(io::Error),
+}
+
+impl From<io::Error> for ErrorKind {
+    fn from(e: io::Error) -> ErrorKind {
+        ErrorKind::IoError(e)
+    }
 }
 
 struct FormattingError {
@@ -162,7 +168,9 @@ impl FormattingError {
     }
     fn msg_prefix(&self) -> &str {
         match self.kind {
-            ErrorKind::LineOverflow(..) | ErrorKind::TrailingWhitespace => "internal error:",
+            ErrorKind::LineOverflow(..) | ErrorKind::TrailingWhitespace | ErrorKind::IoError(_) => {
+                "internal error:"
+            }
             ErrorKind::LicenseCheck | ErrorKind::BadAttr => "error:",
             ErrorKind::BadIssue(_) | ErrorKind::DeprecatedAttr => "warning:",
         }
@@ -244,6 +252,7 @@ impl FormatReport {
                 | ErrorKind::BadAttr => {
                     errs.has_check_errors = true;
                 }
+                _ => {}
             }
         }
     }
@@ -469,7 +478,7 @@ fn should_report_error(
     config: &Config,
     char_kind: FullCodeCharKind,
     is_string: bool,
-    error_kind: ErrorKind,
+    error_kind: &ErrorKind,
 ) -> bool {
     let allow_error_report = if char_kind.is_comment() || is_string {
         config.error_on_unformatted()
@@ -541,7 +550,8 @@ fn format_lines(
             if format_line {
                 // Check for (and record) trailing whitespace.
                 if let Some(..) = last_wspace {
-                    if should_report_error(config, kind, is_string, ErrorKind::TrailingWhitespace) {
+                    if should_report_error(config, kind, is_string, &ErrorKind::TrailingWhitespace)
+                    {
                         trims.push((cur_line, kind, line_buffer.clone()));
                     }
                     line_len -= 1;
@@ -551,7 +561,7 @@ fn format_lines(
                 let error_kind = ErrorKind::LineOverflow(line_len, config.max_width());
                 if line_len > config.max_width()
                     && !is_skipped_line(cur_line, skipped_range)
-                    && should_report_error(config, kind, is_string, error_kind)
+                    && should_report_error(config, kind, is_string, &error_kind)
                 {
                     errors.push(FormattingError {
                         line: cur_line,
@@ -967,7 +977,7 @@ pub enum Input {
     Text(String),
 }
 
-pub fn format_and_emit_report(input: Input, config: &Config) -> FmtResult<Summary> {
+pub fn format_and_emit_report(input: Input, config: &Config) -> Result<Summary, failure::Error> {
     if !config.version_meets_requirement() {
         return Err(format_err!("Version mismatch"));
     }
@@ -1000,15 +1010,15 @@ pub fn format_and_emit_report(input: Input, config: &Config) -> FmtResult<Summar
     }
 }
 
-pub fn emit_pre_matter(config: &Config) -> FmtResult<()> {
+pub fn emit_pre_matter(config: &Config) -> Result<(), ErrorKind> {
     if config.write_mode() == WriteMode::Checkstyle {
         let mut out = &mut stdout();
         checkstyle::output_header(&mut out)?;
     }
     Ok(())
 }
 
-pub fn emit_post_matter(config: &Config) -> FmtResult<()> {
+pub fn emit_post_matter(config: &Config) -> Result<(), ErrorKind> {
     if config.write_mode() == WriteMode::Checkstyle {
         let mut out = &mut stdout();
         checkstyle::output_footer(&mut out)?;