hashsum: implement the ignore-missing option

src/uu/hashsum/src/hashsum.rs

@@ -21,7 +21,7 @@ use std::iter;
 use std::num::ParseIntError;
 use std::path::Path;
 use uucore::error::USimpleError;
-use uucore::error::{FromIo, UError, UResult};
+use uucore::error::{set_exit_code, FromIo, UError, UResult};
 use uucore::sum::{
     Blake2b, Blake3, Digest, DigestWriter, Md5, Sha1, Sha224, Sha256, Sha384, Sha3_224, Sha3_256,
     Sha3_384, Sha3_512, Sha512, Shake128, Shake256,
@@ -46,6 +46,7 @@ struct Options {
     warn: bool,
     output_bits: usize,
     zero: bool,
+    ignore_missing: bool,
 }
 
 /// Creates a Blake2b hasher instance based on the specified length argument.
@@ -345,6 +346,12 @@ pub fn uumain(mut args: impl uucore::Args) -> UResult<()> {
     let strict = matches.get_flag("strict");
     let warn = matches.get_flag("warn") && !status;
     let zero = matches.get_flag("zero");
+    let ignore_missing = matches.get_flag("ignore-missing");
+
+    if ignore_missing && !check {
+        // --ignore-missing needs -c
+        return Err(HashsumError::IgnoreNotCheck.into());
+    }
 
     let opts = Options {
         algoname: name,
@@ -359,6 +366,7 @@ pub fn uumain(mut args: impl uucore::Args) -> UResult<()> {
         strict,
         warn,
         zero,
+        ignore_missing,
     };
 
     match matches.get_many::<OsString>("FILE") {
@@ -431,6 +439,12 @@ pub fn uu_app_common() -> Command {
                 .help("exit non-zero for improperly formatted checksum lines")
                 .action(ArgAction::SetTrue),
         )
+        .arg(
+            Arg::new("ignore-missing")
+                .long("ignore-missing")
+                .help("don't fail or report status for missing files")
+                .action(ArgAction::SetTrue),
+        )
         .arg(
             Arg::new("warn")
                 .short('w')
@@ -564,6 +578,7 @@ fn uu_app(binary_name: &str) -> Command {
 enum HashsumError {
     InvalidRegex,
     InvalidFormat,
+    IgnoreNotCheck,
 }
 
 impl Error for HashsumError {}
@@ -574,6 +589,10 @@ impl std::fmt::Display for HashsumError {
         match self {
             Self::InvalidRegex => write!(f, "invalid regular expression"),
             Self::InvalidFormat => Ok(()),
+            Self::IgnoreNotCheck => write!(
+                f,
+                "the --ignore-missing option is meaningful only when verifying checksums"
+            ),
         }
     }
 }
@@ -705,13 +724,19 @@ where
                 let (ck_filename_unescaped, prefix) = unescape_filename(&ck_filename);
                 let f = match File::open(ck_filename_unescaped) {
                     Err(_) => {
+                        if options.ignore_missing {
+                            // No need to show or return an error.
+                            continue;
+                        }
+
                         failed_open_file += 1;
                         println!(
                             "{}: {}: No such file or directory",
                             uucore::util_name(),
                             ck_filename
                         );
                         println!("{ck_filename}: FAILED open or read");
+                        set_exit_code(1);
                         continue;
                     }
                     Ok(file) => file,

tests/by-util/test_hashsum.rs

@@ -129,6 +129,40 @@ fn test_check_sha1() {
         .stderr_is("");
 }
 
+#[test]
+fn test_check_md5_ignore_missing() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.write("testf", "foobar\n");
+    at.write(
+        "testf.sha1",
+        "14758f1afd44c09b7992073ccf00b43d  testf\n14758f1afd44c09b7992073ccf00b43d  testf2\n",
+    );
+    scene
+        .ccmd("md5sum")
+        .arg("-c")
+        .arg(at.subdir.join("testf.sha1"))
+        .fails()
+        .stdout_contains("testf2: FAILED open or read");
+
+    scene
+        .ccmd("md5sum")
+        .arg("-c")
+        .arg("--ignore-missing")
+        .arg(at.subdir.join("testf.sha1"))
+        .succeeds()
+        .stdout_is("testf: OK\n")
+        .stderr_is("");
+
+    scene
+        .ccmd("md5sum")
+        .arg("--ignore-missing")
+        .arg(at.subdir.join("testf.sha1"))
+        .fails()
+        .stderr_contains("the --ignore-missing option is meaningful only when verifying checksums");
+}
+
 #[test]
 fn test_check_b2sum_length_option_0() {
     let scene = TestScenario::new(util_name!());
@@ -208,7 +242,7 @@ fn test_check_file_not_found_warning() {
         .ccmd("sha1sum")
         .arg("-c")
         .arg(at.subdir.join("testf.sha1"))
-        .succeeds()
+        .fails()
         .stdout_is("sha1sum: testf: No such file or directory\ntestf: FAILED open or read\n")
         .stderr_is("sha1sum: warning: 1 listed file could not be read\n");
 }