Use fatal() to exit with errorcode 2 (#739)

* Fix two typos

* Dismantle two Pyramids of Doom

Use question mark operator instead

* Use fatal() to exit with errorcode 2

12 files changed, 70 insertions, 97 deletions

diff --git a/src/bat_utils/output.rs b/src/bat_utils/output.rs
index 51819787..a5251a0c 100644
--- a/src/bat_utils/output.rs
+++ b/src/bat_utils/output.rs
@@ -10,6 +10,7 @@ use std::process::{Child, Command, Stdio};
 use super::less::retrieve_less_version;
 
 use crate::config;
+use crate::fatal;
 use crate::features::navigate;
 
 #[derive(Debug, Clone, Copy, PartialEq)]
@@ -177,14 +178,13 @@ fn _make_process_from_less_path(
 
 fn _make_process_from_pager_path(pager_path: PathBuf, args: &[String]) -> Option<Command> {
     if pager_path.file_stem() == Some(&OsString::from("delta")) {
-        eprintln!(
+        fatal(
             "\
 It looks like you have set delta as the value of $PAGER. \
 This would result in a non-terminating recursion. \
 delta is not an appropriate value for $PAGER \
-(but it is an appropriate value for $GIT_PAGER)."
+(but it is an appropriate value for $GIT_PAGER).",
         );
-        std::process::exit(1);
     }
     if let Ok(pager_path) = grep_cli::resolve_binary(pager_path) {
         let mut p = Command::new(&pager_path);
diff --git a/src/cli.rs b/src/cli.rs
index 1281bd9a..12db6e2a 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -443,7 +443,7 @@ pub struct Opt {
 
     /// Default language used for syntax highlighting when this cannot be
     /// inferred from a filename. It will typically make sense to set this in
-    /// per-repository git config ().git/config)
+    /// per-repository git config (.git/config)
     #[structopt(long = "default-language")]
     pub default_language: Option<String>,
 
diff --git a/src/color.rs b/src/color.rs
index e7c3f62f..dfa86fa7 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -1,5 +1,4 @@
 use std::collections::HashMap;
-use std::process;
 use std::str::FromStr;
 
 use ansi_term::Color;
@@ -7,6 +6,7 @@ use lazy_static::lazy_static;
 use syntect::highlighting::Color as SyntectColor;
 
 use crate::bat_utils::terminal::to_ansi_color;
+use crate::fatal;
 use crate::syntect_utils;
 
 pub fn parse_color(s: &str, true_color: bool) -> Option<Color> {
@@ -14,8 +14,7 @@ pub fn parse_color(s: &str, true_color: bool) -> Option<Color> {
         return None;
     }
     let die = || {
-        eprintln!("Invalid color or style attribute: {}", s);
-        process::exit(1);
+        fatal(format!("Invalid color or style attribute: {}", s));
     };
     let syntect_color = if s.starts_with('#') {
         SyntectColor::from_str(s).unwrap_or_else(|_| die())
diff --git a/src/config.rs b/src/config.rs
index 4074551b..15860a80 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,6 +1,5 @@
 use std::collections::HashMap;
 use std::path::PathBuf;
-use std::process;
 
 use regex::Regex;
 use structopt::clap;
@@ -185,23 +184,21 @@ impl From<cli::Opt> for Config {
                 .unwrap_or(0.0);
 
         let commit_regex = Regex::new(&opt.commit_regex).unwrap_or_else(|_| {
-            eprintln!(
+            fatal(format!(
                 "Invalid commit-regex: {}. \
                  The value must be a valid Rust regular expression. \
                  See https://docs.rs/regex.",
                 opt.commit_regex
-            );
-            process::exit(1);
+            ));
         });
 
         let tokenization_regex = Regex::new(&opt.tokenization_regex).unwrap_or_else(|_| {
-            eprintln!(
+            fatal(format!(
                 "Invalid word-diff-regex: {}. \
                  The value must be a valid Rust regular expression. \
                  See https://docs.rs/regex.",
                 opt.tokenization_regex
-            );
-            process::exit(1);
+            ));
         });
 
         let side_by_side_data = side_by_side::SideBySideData::new_sbs(
@@ -613,13 +610,11 @@ pub fn user_supplied_option(option: &str, arg_matches: &clap::ArgMatches) -> boo
 }
 
 pub fn delta_unreachable(message: &str) -> ! {
-    let error_exit_code = 2; // This is also stored in Config.
-    eprintln!(
+    fatal(format!(
         "{} This should not be possible. \
          Please report the bug at https://github.com/dandavison/delta/issues.",
         message
-    );
-    process::exit(error_exit_code);
+    ));
 }
 
 #[cfg(test)]
diff --git a/src/git_config/mod.rs b/src/git_config/mod.rs
index 1b2ea0a6..9b9f11ff 100644
--- a/src/git_config/mod.rs
+++ b/src/git_config/mod.rs
@@ -7,7 +7,8 @@ use std::collections::HashMap;
 use std::env;
 #[cfg(test)]
 use std::path::Path;
-use std::process;
+
+use crate::fatal;
 
 use lazy_static::lazy_static;
 
@@ -31,8 +32,7 @@ impl GitConfig {
         match config {
             Some(mut config) => {
                 let config = config.snapshot().unwrap_or_else(|err| {
-                    eprintln!("Failed to read git config: {}", err);
-                    process::exit(1)
+                    fatal(format!("Failed to read git config: {}", err));
                 });
                 Some(Self {
                     config,
diff --git a/src/handlers/blame.rs b/src/handlers/blame.rs
index 2c1b2222..31fb1315 100644
--- a/src/handlers/blame.rs
+++ b/src/handlers/blame.rs
@@ -109,30 +109,25 @@ $
 }
 
 pub fn parse_git_blame_line<'a>(line: &'a str, timestamp_format: &str) -> Option<BlameLine<'a>> {
-    if let Some(caps) = BLAME_LINE_REGEX.captures(line) {
-        let commit = caps.get(1).unwrap().as_str();
-        let author = caps.get(2).unwrap().as_str();
-        let timestamp = caps.get(3).unwrap().as_str();
-        if let Ok(time) = DateTime::parse_from_str(timestamp, timestamp_format) {
-            let line_number_str = caps.get(4).unwrap().as_str();
-            if let Ok(line_number) = line_number_str.parse::<usize>() {
-                let code = caps.get(5).unwrap().as_str();
-                Some(BlameLine {
-                    commit,
-                    author,
-                    time,
-                    line_number,
-                    code,
-                })
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    } else {
-        None
-    }
+    let caps = BLAME_LINE_REGEX.captures(line)?;
+
+    let commit = caps.get(1).unwrap().as_str();
+    let author = caps.get(2).unwrap().as_str();
+    let timestamp = caps.get(3).unwrap().as_str();
+
+    let time = DateTime::parse_from_str(timestamp, timestamp_format).ok()?;
+
+    let line_number = caps.get(4).unwrap().as_str().parse::<usize>().ok()?;
+
+    let code = caps.get(5).unwrap().as_str();
+
+    Some(BlameLine {
+        commit,
+        author,
+        time,
+        line_number,
+        code,
+    })
 }
 
 lazy_static! {
diff --git a/src/handlers/diff_stat.rs b/src/handlers/diff_stat.rs
index 39a2130f..d8e9c847 100644
--- a/src/handlers/diff_stat.rs
+++ b/src/handlers/diff_stat.rs
@@ -46,20 +46,16 @@ pub fn relativize_path_in_diff_stat_line(
     cwd_relative_to_repo_root: &str,
     diff_stat_align_width: usize,
 ) -> Option<String> {
-    if let Some(caps) = DIFF_STAT_LINE_REGEX.captures(line) {
-        let path_relative_to_repo_root = caps.get(1).unwrap().as_str();
-        if let Some(relative_path) =
-            pathdiff::diff_paths(path_relative_to_repo_root, cwd_relative_to_repo_root)
-        {
-            if let Some(relative_path) = relative_path.to_str() {
-                let suffix = caps.get(2).unwrap().as_str();
-                let pad_width = diff_stat_align_width.saturating_sub(relative_path.len());
-                let padding = " ".repeat(pad_width);
-                return Some(format!(" {}{}{}", relative_path, padding, suffix));
-            }
-        }
-    }
-    None
+    let caps = DIFF_STAT_LINE_REGEX.captures(line)?;
+    let path_relative_to_repo_root = caps.get(1).unwrap().as_str();
+
+    let relative_path =
+        pathdiff::diff_paths(path_relative_to_repo_root, cwd_relative_to_repo_root)?;
+    let relative_path = relative_path.to_str()?;
+    let suffix = caps.get(2).unwrap().as_str();
+    let pad_width = diff_stat_align_width.saturating_sub(relative_path.len());
+    let padding = " ".repeat(pad_width);
+    Some(format!(" {}{}{}", relative_path, padding, suffix))
 }
 
 #[cfg(test)]
diff --git a/src/main.rs b/src/main.rs
index 22f0c7aa..0955f90d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -45,6 +45,8 @@ where
     #[cfg(not(test))]
     {
         eprintln!("{}", errmsg);
+        // As in Config::error_exit_code: use 2 for error
+        // because diff uses 0 and 1 for non-error.
         process::exit(2);
     }
     #[cfg(test)]
diff --git a/src/options/rewrite.rs b/src/options/rewrite.rs
index 1c4759e6..11bd0639 100644
--- a/src/options/rewrite.rs
+++ b/src/options/rewrite.rs
@@ -2,12 +2,11 @@
 /// 1. Express deprecated usages in the new non-deprecated form
 /// 2. Implement options such as --raw which are defined to be equivalent to some set of
 ///    other options.
-use std::process;
-
 use structopt::clap;
 
 use crate::cli;
 use crate::config::user_supplied_option;
+use crate::fatal;
 
 pub fn apply_rewrite_rules(opt: &mut cli::Opt, arg_matches: &clap::ArgMatches) {
     rewrite_style_strings_to_honor_deprecated_minus_plus_options(opt);
@@ -102,10 +101,9 @@ fn rewrite_options_to_implement_deprecated_hunk_style_option(opt: &mut cli::Opt)
         // apparently been left at its default value.
         let hunk_header_decoration_default = "blue box";
         if opt.hunk_header_decoration_style != hunk_header_decoration_default {
-            eprintln!(
-                "Deprecated option --hunk-style cannot be used with --hunk-header-decoration-style. \
-                 Use --hunk-header-decoration-style.");
-            process::exit(1);
+            fatal(
+                  "Deprecated option --hunk-style cannot be used with --hunk-header-decoration-style. \
+                   Use --hunk-header-decoration-style.");
         }
         match opt.deprecated_hunk_style.as_deref().map(str::to_lowercase) {
             Some(attr) if attr == "plain" => opt.hunk_header_decoration_style = "".to_string(),
@@ -163,25 +161,23 @@ fn _get_rewritten_minus_plus_style_string(
             )))
         }
         (_, (_, Some(_))) => {
-            eprintln!(
+            fatal(format!(
                 "--{name}-color cannot be used with --{name}-style. \
                  Use --{name}-style=\"fg bg attr1 attr2 ...\" to set \
                  foreground color, background color, and style attributes. \
                  --{name}-color can only be used to set the background color. \
                  (It is still available for backwards-compatibility.)",
                 name = element_name,
-            );
-            process::exit(1);
+            ));
         }
         (_, (Some(_), None)) => {
-            eprintln!(
+            fatal(format!(
                 "Deprecated option --highlight-removed cannot be used with \
                  --{name}-style. Use --{name}-style=\"fg bg attr1 attr2 ...\" \
                  to set foreground color, background color, and style \
                  attributes.",
                 name = element_name,
-            );
-            process::exit(1);
+            ));
         }
     }
 }
diff --git a/src/options/set.rs b/src/options/set.rs
index 18c10118..c8a700e2 100644
--- a/src/options/set.rs
+++ b/src/options/set.rs
@@ -1,6 +1,5 @@
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::convert::TryInto;
-use std::process;
 use std::result::Result;
 use std::str::FromStr;
 
@@ -230,8 +229,7 @@ fn set__light__dark__syntax_theme__options(
 ) {
     let validate_light_and_dark = |opt: &cli::Opt| {
         if opt.light && opt.dark {
-            eprintln!("--light and --dark cannot be used together.");
-            process::exit(1);
+            fatal("--light and --dark cannot be used together.");
         }
     };
     let empty_builtin_features = HashMap::new();
@@ -498,11 +496,10 @@ impl FromStr for cli::InspectRawLines {
             "true" => Ok(Self::True),
             "false" => Ok(Self::False),
             _ => {
-                eprintln!(
+                fatal(format!(
                     r#"Invalid value for inspect-raw-lines option: {}. Valid values are "true", and "false"."#,
                     s
-                );
-                process::exit(1);
+                ));
             }
         }
     }
@@ -514,11 +511,10 @@ fn parse_paging_mode(paging_mode_string: &str) -> PagingMode {
         "never" => PagingMode::Never,
         "auto" => PagingMode::QuitIfOneScreen,
         _ => {
-            eprintln!(
+            fatal(format!(
                 "Invalid value for --paging option: {} (valid values are \"always\", \"never\", and \"auto\")",
                 paging_mode_string
-            );
-            process::exit(1);
+            ));
         }
     }
 }
@@ -610,11 +606,10 @@ fn set_true_color(opt: &mut cli::Opt) {
         "never" => false,
         "auto" => is_truecolor_terminal(),
         _ => {
-            eprintln!(
+            fatal(format!(
                 "Invalid value for --true-color option: {} (valid values are \"always\", \"never\", and \"auto\")",
                 opt.true_color
-            );
-            process::exit(1);
+            ));
         }
     };
 }
diff --git a/src/parse_style.rs b/src/parse_style.rs
index 1c20c981..49299fa9 100644
--- a/src/parse_style.rs
+++ b/src/parse_style.rs
@@ -1,9 +1,8 @@
-use std::process;
-
 use bitflags::bitflags;
 
 use crate::color;
 use crate::config::delta_unreachable;
+use crate::fatal;
 use crate::style::{DecorationStyle, Style};
 
 impl Style {
@@ -136,12 +135,10 @@ impl DecorationStyle {
         let (style, is_omitted, is_raw, is_syntax_highlighted) =
             parse_ansi_term_style(&style_string, None, true_color);
         if is_raw {
-            eprintln!("'raw' may not be used in a decoration style.");
-            process::exit(1);
+            fatal("'raw' may not be used in a decoration style.");
         };
         if is_syntax_highlighted {
-            eprintln!("'syntax' may not be used in a decoration style.");
-            process::exit(1);
+            fatal("'syntax' may not be used in a decoration style.");
         };
         #[allow(non_snake_case)]
         let (BOX, UL, OL, EMPTY) = (
@@ -256,12 +253,11 @@ fn parse_ansi_term_style(
             seen_foreground = true;
         } else if !seen_background {
             if word == "syntax" {
-                eprintln!(
+                fatal(
                     "You have used the special color 'syntax' as a background color \
-                     (second color in a style string). It may only be used as a foreground \
-                     color (first color in a style string)."
+                       (second color in a style string). It may only be used as a foreground \
+                       color (first color in a style string).",
                 );
-                process::exit(1);
             } else if word == "auto" {
                 background_is_auto = true;
                 style.background = default.and_then(|s| s.ansi_term_style.background);
@@ -270,11 +266,10 @@ fn parse_ansi_term_style(
             }
             seen_background = true;
         } else {
-            eprintln!(
+            fatal(format!(
                 "Invalid style string: {}. See the STYLES section of delta --help.",
                 s
-            );
-            process::exit(1);
+            ));
         }
     }
     if foreground_is_auto && background_is_auto {
diff --git a/src/subcommands/show_config.rs b/src/subcommands/show_config.rs
index 254c5e30..5442ae1f 100644
--- a/src/subcommands/show_config.rs
+++ b/src/subcommands/show_config.rs
@@ -100,7 +100,7 @@ pub fn show_config(config: &config::Config, writer: &mut dyn Write) -> std::io::
         writer,
         "    max-line-distance             = {max_line_distance}
     max-line-length               = {max_line_length}
-    line-fill-method        = {line_fill_method}
+    line-fill-method              = {line_fill_method}
     navigate                      = {navigate}
     navigate-regexp               = {navigate_regexp}
     pager                         = {pager}