Improve error handling

Author: Marek Suchánek

src/lib.rs

@@ -11,7 +11,7 @@
 #![forbid(unsafe_code)]
 
 use clap::ArgMatches;
-use color_eyre::eyre::Result;
+use color_eyre::eyre::{bail, eyre, Result, WrapErr};
 
 pub mod cmd_line;
 mod logging;
@@ -114,8 +114,11 @@ pub fn run(options: &Options, cmdline_args: &ArgMatches) -> Result<()> {
             .map(|module| module.include_statement)
             .collect();
 
-        // The include_statements should never be empty thanks to the required group in clap
-        assert!(!include_statements.is_empty());
+        // The include_statements should never be empty thanks to the required group in clap.
+        // Make sure once more, though.
+        if include_statements.is_empty() {
+            bail!("The populated assembly includes no other files.");
+        }
 
         // Generate the populated assembly module
         let populated: Module = Input::new(ContentType::Assembly, title, options)
@@ -128,7 +131,8 @@ pub fn run(options: &Options, cmdline_args: &ArgMatches) -> Result<()> {
     // Validate all file names specified on the command line
     if let Some(files_iterator) = cmdline_args.values_of("validate") {
         for file in files_iterator {
-            validation::validate(file)?;
+            validation::validate(file)
+                .wrap_err_with(|| eyre!("Failed to validate file {:?}", file))?;
         }
     }
 

src/validation.rs

@@ -291,8 +291,12 @@ mod title {
 
         let attribute_regex = Regex::new(r"\{((?:[[:alnum:]]|[-_])+)\}").expect(REGEX_ERROR);
         let attribute = attribute_regex.captures(mod_id)?;
+        let attribute_name = attribute
+            .get(1)
+            .expect("Failed to extract an attribute name. Please report this as a bug")
+            .as_str();
 
-        if attribute.get(1).unwrap().as_str() == "context" {
+        if attribute_name == "context" {
             // The context attribute is allowed
             None
         } else {

src/write.rs

@@ -2,7 +2,7 @@ use std::fs;
 use std::io;
 use std::path::PathBuf;
 
-use color_eyre::eyre::{Context, Result};
+use color_eyre::eyre::{eyre, Result, WrapErr};
 
 use crate::module::Module;
 use crate::Options;
@@ -26,7 +26,7 @@ impl Module {
 
             io::stdin()
                 .read_line(&mut answer)
-                .context("Failed to read your response")?;
+                .wrap_err_with(|| eyre!("Failed to read your response: {:?}", answer))?;
 
             match answer.trim().to_lowercase().as_str() {
                 "y" | "yes" => {
@@ -42,10 +42,8 @@ impl Module {
         }
 
         // If the target file doesn't exist, try to write to it
-        fs::write(full_path, &self.text).context(format!(
-            "Failed to write the `{}` file.",
-            &full_path.display()
-        ))?;
+        fs::write(full_path, &self.text)
+            .wrap_err_with(|| eyre!("Failed to write the `{}` file.", &full_path.display()))?;
 
         // If the write succeeds, print the include statement
         log::debug!("Successfully written file `{}`", &full_path.display());