Fix to not show style decorations in auto mode when piping

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Fix hang when using `--list-themes` with an explicit pager, see #3457 (@abhinavcool42)
 - Fix negative values of N not being parsed in <N:M> line ranges without `=` flag value separator, see #3442 (@lmmx)
 - Fix broken Docker syntax preventing use of custom assets, see #3476 (@keith-hall)
+- Fix decorations being applied unexpectedly when piping, breaking cat compatibility. See #3496 (@keith-hall)
 
 ## Other
 - Improve README documentation on pager options passed to less, see #3443 (@injust)

src/bin/bat/app.rs

@@ -384,8 +384,7 @@ impl App {
                     .map(|s| s.as_str())
                     == Some("always")
                 || self.matches.get_flag("force-colorization")
-                || self.matches.get_flag("number")
-                || self.matches.contains_id("style") && !style_components.plain()),
+                || self.matches.get_flag("number")),
             tab_width: self
                 .matches
                 .get_one::<String>("tabs")

tests/integration_tests.rs

@@ -415,7 +415,7 @@ fn piped_output_with_line_numbers_style_flag() {
         .write_stdin("hello\nworld\n")
         .assert()
         .success()
-        .stdout("   1 hello\n   2 world\n");
+        .stdout("hello\nworld\n");
 }
 
 #[test]
@@ -426,15 +426,7 @@ fn piped_output_with_line_numbers_with_header_grid_style_flag() {
         .write_stdin("hello\nworld\n")
         .assert()
         .success()
-        .stdout(
-            "─────┬──────────────────────────────────────────────────────────────────────────
-     │ STDIN
-─────┼──────────────────────────────────────────────────────────────────────────
-   1 │ hello
-   2 │ world
-─────┴──────────────────────────────────────────────────────────────────────────
-",
-        );
+        .stdout("hello\nworld\n");
 }
 
 #[test]
@@ -452,6 +444,7 @@ fn piped_output_with_auto_style() {
 fn piped_output_with_default_style_flag() {
     bat()
         .arg("--style=default")
+        .arg("--decorations=always")
         .write_stdin("hello\nworld\n")
         .assert()
         .success()