core: don't let context flags override eachother

This matches the behavior of GNU grep which does not ignore
before-context and after-context completely if the context flag is also
provided.

Note that this change wasn't done just to match GNU grep. In this case,
GNU grep has the more sensible behavior.

Fixes #2288, Closes #2451

CHANGELOG.md

@@ -2,6 +2,12 @@ TBD
 ===
 Unreleased changes. Release notes have not yet been written.
 
+**BREAKING CHANGES**
+
+* `rg -C1 -A2` used to be equivalent to `rg -A2`, but now it is equivalent to
+  `rg -B1 -A2`. That is, `-A` and `-B` no longer completely override `-C`.
+  Instead, they only partially override `-C`.
+
 Feature enhancements:
 
 * Added or improved file type filtering for Fuchsia, GraphQL
@@ -12,6 +18,8 @@ Bug fixes:
   Fix bug when using `-w` with a regex that can match the empty string.
 * [BUG #1911](https://github.com/BurntSushi/ripgrep/issues/1911):
   Disable mmap searching in all non-64-bit environments.
+* [BUG #2288](https://github.com/BurntSushi/ripgrep/issues/2288):
+  `-A` and `-B` now only each partially override `-C`.
 * [BUG #2236](https://github.com/BurntSushi/ripgrep/issues/2236):
   Fix gitignore parsing bug where a trailing `\/` resulted in an error.
 * [BUG #2480](https://github.com/BurntSushi/ripgrep/issues/2480):

crates/core/app.rs

@@ -698,16 +698,15 @@ fn flag_after_context(args: &mut Vec<RGArg>) {
         "\
 Show NUM lines after each match.
 
-This overrides the --context and --passthru flags.
+This overrides the --passthru flag and partially overrides --context.
 "
     );
     let arg = RGArg::flag("after-context", "NUM")
         .short("A")
         .help(SHORT)
         .long_help(LONG)
         .number()
-        .overrides("passthru")
-        .overrides("context");
+        .overrides("passthru");
     args.push(arg);
 }
 
@@ -768,16 +767,15 @@ fn flag_before_context(args: &mut Vec<RGArg>) {
         "\
 Show NUM lines before each match.
 
-This overrides the --context and --passthru flags.
+This overrides the --passthru flag and partially overrides --context.
 "
     );
     let arg = RGArg::flag("before-context", "NUM")
         .short("B")
         .help(SHORT)
         .long_help(LONG)
         .number()
-        .overrides("passthru")
-        .overrides("context");
+        .overrides("passthru");
     args.push(arg);
 }
 
@@ -1009,18 +1007,15 @@ fn flag_context(args: &mut Vec<RGArg>) {
 Show NUM lines before and after each match. This is equivalent to providing
 both the -B/--before-context and -A/--after-context flags with the same value.
 
-This overrides both the -B/--before-context and -A/--after-context flags,
-in addition to the --passthru flag.
+This overrides the --passthru flag.
 "
     );
     let arg = RGArg::flag("context", "NUM")
         .short("C")
         .help(SHORT)
         .long_help(LONG)
         .number()
-        .overrides("passthru")
-        .overrides("before-context")
-        .overrides("after-context");
+        .overrides("passthru");
     args.push(arg);
 }
 

crates/core/args.rs

@@ -992,10 +992,10 @@ impl ArgMatches {
     /// If there was a problem parsing the values from the user as an integer,
     /// then an error is returned.
     fn contexts(&self) -> Result<(usize, usize)> {
-        let after = self.usize_of("after-context")?.unwrap_or(0);
-        let before = self.usize_of("before-context")?.unwrap_or(0);
         let both = self.usize_of("context")?.unwrap_or(0);
-        Ok(if both > 0 { (both, both) } else { (before, after) })
+        let after = self.usize_of("after-context")?.unwrap_or(both);
+        let before = self.usize_of("before-context")?.unwrap_or(both);
+        Ok((before, after))
     }
 
     /// Returns the unescaped context separator in UTF-8 bytes.

tests/feature.rs

@@ -921,6 +921,23 @@ rgtest!(f1842_field_match_separator, |dir: Dir, _: TestCommand| {
     eqnice!(expected, dir.command().args(&args).stdout());
 });
 
+// See: https://github.com/BurntSushi/ripgrep/issues/2288
+rgtest!(f2288_context_partial_override, |dir: Dir, mut cmd: TestCommand| {
+    dir.create("test", "1\n2\n3\n4\n5\n6\n7\n8\n9\n");
+    cmd.args(&["-C1", "-A2", "5", "test"]);
+    eqnice!("4\n5\n6\n7\n", cmd.stdout());
+});
+
+// See: https://github.com/BurntSushi/ripgrep/issues/2288
+rgtest!(
+    f2288_context_partial_override_rev,
+    |dir: Dir, mut cmd: TestCommand| {
+        dir.create("test", "1\n2\n3\n4\n5\n6\n7\n8\n9\n");
+        cmd.args(&["-A2", "-C1", "5", "test"]);
+        eqnice!("4\n5\n6\n7\n", cmd.stdout());
+    }
+);
+
 rgtest!(no_context_sep, |dir: Dir, mut cmd: TestCommand| {
     dir.create("test", "foo\nctx\nbar\nctx\nfoo\nctx");
     cmd.args(&["-A1", "--no-context-separator", "foo", "test"]);