printer: support -r/--replace with --json

This adds a `replacement` field to each submatch object in the JSON
output. In effect, this extends the `-r/--replace` flag so that it works
with `--json`.

This adds a new field instead of replacing the match text (which is how
the standard printer works) for maximum flexibility. This way, consumers
of the JSON output can access the original match text (and always rely
on it corresponding to the original match text) while also getting the
replacement text without needing to do the replacement themselves.

Closes #1872, Closes #2883

tests/json.rs

@@ -55,11 +55,13 @@ impl Message {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Begin {
     path: Option<Data>,
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct End {
     path: Option<Data>,
     binary_offset: Option<u64>,
@@ -67,12 +69,14 @@ struct End {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Summary {
     elapsed_total: Duration,
     stats: Stats,
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Match {
     path: Option<Data>,
     lines: Data,
@@ -82,6 +86,7 @@ struct Match {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Context {
     path: Option<Data>,
     lines: Data,
@@ -91,9 +96,11 @@ struct Context {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct SubMatch {
     #[serde(rename = "match")]
     m: Data,
+    replacement: Option<Data>,
     start: usize,
     end: usize,
 }
@@ -117,6 +124,7 @@ impl Data {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Stats {
     elapsed: Duration,
     searches: u64,
@@ -128,6 +136,7 @@ struct Stats {
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
 struct Duration {
     #[serde(flatten)]
     duration: time::Duration,
@@ -178,6 +187,7 @@ rgtest!(basic, |dir: Dir, mut cmd: TestCommand| {
             absolute_offset: 129,
             submatches: vec![SubMatch {
                 m: Data::text("Sherlock Holmes"),
+                replacement: None,
                 start: 48,
                 end: 63,
             },],
@@ -189,6 +199,57 @@ rgtest!(basic, |dir: Dir, mut cmd: TestCommand| {
     assert_eq!(msgs[4].unwrap_summary().stats.bytes_printed, 494);
 });
 
+rgtest!(replacement, |dir: Dir, mut cmd: TestCommand| {
+    dir.create("sherlock", SHERLOCK);
+    cmd.arg("--json")
+        .arg("-B1")
+        .arg("Sherlock Holmes")
+        .args(["-r", "John Watson"])
+        .arg("sherlock");
+
+    let msgs = json_decode(&cmd.stdout());
+
+    assert_eq!(
+        msgs[0].unwrap_begin(),
+        Begin { path: Some(Data::text("sherlock")) }
+    );
+    assert_eq!(
+        msgs[1].unwrap_context(),
+        Context {
+            path: Some(Data::text("sherlock")),
+            lines: Data::text(
+                "Holmeses, success in the province of \
+                 detective work must always\n",
+            ),
+            line_number: Some(2),
+            absolute_offset: 65,
+            submatches: vec![],
+        }
+    );
+    assert_eq!(
+        msgs[2].unwrap_match(),
+        Match {
+            path: Some(Data::text("sherlock")),
+            lines: Data::text(
+                "be, to a very large extent, the result of luck. \
+                 Sherlock Holmes\n",
+            ),
+            line_number: Some(3),
+            absolute_offset: 129,
+            submatches: vec![SubMatch {
+                m: Data::text("Sherlock Holmes"),
+                replacement: Some(Data::text("John Watson")),
+                start: 48,
+                end: 63,
+            },],
+        }
+    );
+    assert_eq!(msgs[3].unwrap_end().path, Some(Data::text("sherlock")));
+    assert_eq!(msgs[3].unwrap_end().binary_offset, None);
+    assert_eq!(msgs[4].unwrap_summary().stats.searches_with_match, 1);
+    assert_eq!(msgs[4].unwrap_summary().stats.bytes_printed, 531);
+});
+
 rgtest!(quiet_stats, |dir: Dir, mut cmd: TestCommand| {
     dir.create("sherlock", SHERLOCK);
     cmd.arg("--json")
@@ -244,6 +305,7 @@ rgtest!(notutf8, |dir: Dir, mut cmd: TestCommand| {
             absolute_offset: 0,
             submatches: vec![SubMatch {
                 m: Data::bytes("/w=="),
+                replacement: None,
                 start: 4,
                 end: 5,
             },],
@@ -285,6 +347,7 @@ rgtest!(notutf8_file, |dir: Dir, mut cmd: TestCommand| {
             absolute_offset: 0,
             submatches: vec![SubMatch {
                 m: Data::bytes("/w=="),
+                replacement: None,
                 start: 4,
                 end: 5,
             },],
@@ -305,7 +368,12 @@ rgtest!(crlf, |dir: Dir, mut cmd: TestCommand| {
 
     assert_eq!(
         msgs[1].unwrap_match().submatches[0].clone(),
-        SubMatch { m: Data::text("Sherlock"), start: 56, end: 64 },
+        SubMatch {
+            m: Data::text("Sherlock"),
+            replacement: None,
+            start: 56,
+            end: 64
+        },
     );
 });