uniq, split: stop reading an obsolete option after --

src/uu/split/src/split.rs

@@ -76,6 +76,7 @@ fn handle_obsolete(args: impl uucore::Args) -> (Vec<OsString>, Option<String>) {
     let mut obs_lines = None;
     let mut preceding_long_opt_req_value = false;
     let mut preceding_short_opt_req_value = false;
+    let mut after_double_dash = false;
 
     let filtered_args = args
         .filter_map(|os_slice| {
@@ -84,6 +85,7 @@ fn handle_obsolete(args: impl uucore::Args) -> (Vec<OsString>, Option<String>) {
                 &mut obs_lines,
                 &mut preceding_long_opt_req_value,
                 &mut preceding_short_opt_req_value,
+                &mut after_double_dash,
             )
         })
         .collect();
@@ -98,9 +100,19 @@ fn filter_args(
     obs_lines: &mut Option<String>,
     preceding_long_opt_req_value: &mut bool,
     preceding_short_opt_req_value: &mut bool,
+    after_double_dash: &mut bool,
 ) -> Option<OsString> {
     let filter: Option<OsString>;
     if let Some(slice) = os_slice.to_str() {
+        if *after_double_dash {
+            // Past `--` everything is an operand, so `split -- -1` names a file
+            // rather than setting the line count.
+            return Some(OsString::from(slice));
+        }
+        if slice == "--" {
+            *after_double_dash = true;
+            return Some(OsString::from(slice));
+        }
         if should_extract_obs_lines(
             slice,
             *preceding_long_opt_req_value,

src/uu/uniq/src/uniq.rs

@@ -375,6 +375,7 @@ fn handle_obsolete(args: impl uucore::Args) -> (Vec<OsString>, Option<usize>, Op
     let mut skip_chars_old = None;
     let mut preceding_long_opt_req_value = false;
     let mut preceding_short_opt_req_value = false;
+    let mut after_double_dash = false;
 
     let filtered_args = args
         .filter_map(|os_slice| {
@@ -384,6 +385,7 @@ fn handle_obsolete(args: impl uucore::Args) -> (Vec<OsString>, Option<usize>, Op
                 &mut skip_chars_old,
                 &mut preceding_long_opt_req_value,
                 &mut preceding_short_opt_req_value,
+                &mut after_double_dash,
             )
         })
         .collect();
@@ -403,9 +405,19 @@ fn filter_args(
     skip_chars_old: &mut Option<String>,
     preceding_long_opt_req_value: &mut bool,
     preceding_short_opt_req_value: &mut bool,
+    after_double_dash: &mut bool,
 ) -> Option<OsString> {
     let filter: Option<OsString>;
     if let Some(slice) = os_slice.to_str() {
+        if *after_double_dash {
+            // Past `--` everything is an operand, so `uniq -- -1` names a file
+            // rather than skipping a field.
+            return Some(OsString::from(slice));
+        }
+        if slice == "--" {
+            *after_double_dash = true;
+            return Some(OsString::from(slice));
+        }
         if should_extract_obs_skip_fields(
             slice,
             *preceding_long_opt_req_value,

tests/by-util/test_split.rs

@@ -2218,3 +2218,13 @@ split: invalid number of bytes: '7zq'
             .stderr_is("split: invalid number of bytes: '7zq'\n");
     }
 }
+
+#[test]
+fn test_obsolete_lines_not_read_after_double_dash() {
+    // After `--` there are no more options, so `-1` names a file rather than
+    // being taken as the obsolete `split -1` line-count spelling.
+    new_ucmd!()
+        .args(&["--", "-1"])
+        .fails()
+        .stderr_contains("cannot open '-1' for reading");
+}

tests/by-util/test_uniq.rs

@@ -1220,3 +1220,13 @@ fn test_failed_write_is_reported() {
         .fails()
         .stderr_is("uniq: write error: No space left on device\n");
 }
+
+#[test]
+fn test_obsolete_skip_fields_not_read_after_double_dash() {
+    // After `--` there are no more options, so `-1` names a file rather than
+    // being taken as the obsolete "skip 1 field" spelling.
+    new_ucmd!()
+        .args(&["--", "-1"])
+        .fails()
+        .stderr_contains("-1");
+}