Better error reporting

src/lib.rs

@@ -39,19 +39,20 @@ mod common {
 
     #[derive(Default)]
     pub struct WalkResult {
-        pub num_errors: usize,
+        pub num_errors: u64,
     }
 
     impl fmt::Display for WalkResult {
         fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-            write!(f, "Encountered {} IO errors", self.num_errors)
+            write!(f, "Encountered {} IO error(s)", self.num_errors)
         }
     }
 }
 
 mod aggregate {
     use crate::{WalkOptions, WalkResult};
     use failure::Error;
+    use std::borrow::Cow;
     use std::{io, path::Path};
 
     pub fn aggregate(
@@ -65,30 +66,32 @@ mod aggregate {
         for path in paths.into_iter() {
             num_roots += 1;
             let mut num_bytes = 0u64;
+            let mut num_errors = 0u64;
             for entry in options.iter_from_path(path.as_ref()) {
                 match entry {
                     Ok(entry) => {
                         num_bytes += match entry.metadata {
                             Some(Ok(ref m)) if !m.is_dir() => m.len(),
                             Some(Ok(_)) => 0,
                             Some(Err(_)) => {
-                                res.num_errors += 1;
+                                num_errors += 1;
                                 0
                             }
                             None => unreachable!(
                                 "we ask for metadata, so we at least have Some(Err(..))). Issue in jwalk?"
                             ),
                         };
                     }
-                    Err(_) => res.num_errors += 1,
+                    Err(_) => num_errors += 1,
                 }
             }
 
-            write_path(&mut out, &options, path, num_bytes)?;
+            write_path(&mut out, &options, path, num_bytes, num_errors)?;
             total += num_bytes;
+            res.num_errors += num_errors;
         }
         if num_roots > 1 {
-            write_path(&mut out, &options, Path::new("<TOTAL>"), total)?;
+            write_path(&mut out, &options, Path::new("total"), total, res.num_errors)?;
         }
         Ok(res)
     }
@@ -98,12 +101,18 @@ mod aggregate {
         options: &WalkOptions,
         path: impl AsRef<Path>,
         num_bytes: u64,
+        num_errors: u64,
     ) -> Result<(), io::Error> {
         writeln!(
             out,
-            "{}\t{}",
+            "{}\t{}{}",
             options.format_bytes(num_bytes),
-            path.as_ref().display()
+            path.as_ref().display(),
+            if num_errors == 0 {
+                Cow::Borrowed("")
+            } else {
+                Cow::Owned(format!("\t<{} IO Error(s)>", num_errors))
+            }
         )
     }
 }

src/main.rs

@@ -7,7 +7,7 @@ use structopt::StructOpt;
 use dua::ByteFormat;
 use failure::Error;
 use failure_tools::ok_or_exit;
-use std::{io, path::PathBuf};
+use std::{io, path::PathBuf, process};
 
 mod options {
     use dua::ByteFormat as LibraryByteFormat;
@@ -93,7 +93,7 @@ fn run() -> Result<(), Error> {
     }?;
 
     if res.num_errors > 0 {
-        writeln!(io::stderr(), "{}", res).ok();
+        process::exit(1);
     }
     Ok(())
 }

tests/snapshots/failure-no-arguments-multiple-input-paths-some-not-existing

@@ -0,0 +1,6 @@
+1.26 MB	.
+1.26 MB	.
+0.00 B	foo	<1 IO Error(s)>
+0.00 B	bar	<1 IO Error(s)>
+0.00 B	baz	<1 IO Error(s)>
+2.52 MB	total	<3 IO Error(s)>

tests/snapshots/success-no-arguments-multiple-input-paths

@@ -3,4 +3,4 @@
 1.26 MB	dir
 1.26 MB	./dir/
 256.00 KB	./dir/sub
-5.29 MB	<TOTAL>
+5.29 MB	total

tests/stateless-journey.sh

@@ -11,6 +11,7 @@ snapshot="$root/snapshots"
 fixtures="$root/fixtures"
 
 SUCCESSFULLY=0
+WITH_FAILURE=1
 
 (with "a sample directory"
   (sandbox
@@ -36,6 +37,12 @@ SUCCESSFULLY=0
             expect_run ${SUCCESSFULLY} "$exe" . . dir ./dir/ ./dir/sub
           }
         )
+        (when "specifying no subcommand and some of the directories don't exist"
+          it "produces a human-readable (metric) aggregate of the current directory, with total" && {
+            WITH_SNAPSHOT="$snapshot/failure-no-arguments-multiple-input-paths-some-not-existing" \
+            expect_run ${WITH_FAILURE} "$exe" . . foo bar baz
+          }
+        )
       )
     )