grep: make '-o' override context arguments

src/lib.rs

@@ -316,11 +316,17 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         _ => ColorMode::Auto,
     };
     let (before_context, after_context, has_context) = {
-        let fallback = context.unwrap_or(0);
-        let before = before_context.unwrap_or(fallback);
-        let after = after_context.unwrap_or(fallback);
-        let has = context.is_some() || before_context.is_some() || after_context.is_some();
-        (before, after, has)
+        // "-o" overrides any context arguments
+        if only_matching {
+            (0, 0, false)
+        } else {
+            let fallback = context.unwrap_or(0);
+            let before = before_context.unwrap_or(fallback);
+            let after = after_context.unwrap_or(fallback);
+            let has = context.is_some() || before_context.is_some() || after_context.is_some();
+
+            (before, after, has)
+        }
     };
     let include_globs = {
         let mut patterns = GlobSet::with_capacity(include.len());

tests/test_grep.rs

@@ -1696,3 +1696,34 @@ fn fast_path_binary_detected_after_a_printed_line() {
         .stdout_is("hit\n")
         .stderr_contains("binary file matches");
 }
+
+#[test]
+fn only_matching_with_context() {
+    // `only_matching` should override any context arguments.
+    let input = "aa\nbb\ncc\nxx\n";
+
+    let (_s, mut c) = ucmd();
+    c.args(&["aa", "-o", "-A", "2"])
+        .pipe_in(input)
+        .succeeds()
+        .stdout_only("aa\n");
+
+    let (_s, mut c) = ucmd();
+    c.args(&["xx", "-o", "-B", "2"])
+        .pipe_in("aa\nbb\ncc\nxx\n")
+        .succeeds()
+        .stdout_only("xx\n");
+
+    let (_s, mut c) = ucmd();
+    c.args(&["cc", "-o", "-C", "2"])
+        .pipe_in("aa\nbb\ncc\nxx\n")
+        .succeeds()
+        .stdout_only("cc\n");
+
+    // With line numbers.
+    let (_s, mut c) = ucmd();
+    c.args(&["xx", "-o", "-C", "2", "-n"])
+        .pipe_in("aa\nbb\ncc\nxx\n")
+        .succeeds()
+        .stdout_only("4:xx\n");
+}