Support the NO_COLOR environment variable

I ran across this site:

    https://no-color.org/

... which lobbies for tools to recognize the NO_COLOR environment
variable and disable any terminal styling when it is seen.

This patch implements this for gdb.

Regression tested on x86-64 Fedora 38.

Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Reviewed-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 1b91794..de22da8 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -6468,7 +6468,7 @@ proc default_gdb_init { test_file_name } {
 
     # This disables style output, which would interfere with many
     # tests.
-    setenv TERM "dumb"
+    setenv NO_COLOR sorry
 
     # This setting helps detect bugs in the Python code and doesn't
     # seem to have a significant downside for the tests.
@@ -9238,6 +9238,25 @@ proc with_override { name override body } {
     return $result
 }
 
+# Run BODY after setting the TERM environment variable to 'ansi', and
+# unsetting the NO_COLOR environment variable.
+proc with_ansi_styling_terminal { body } {
+    save_vars { ::env(TERM) ::env(NO_COLOR) } {
+	# Set environment variables to allow styling.
+	setenv TERM ansi
+	unset -nocomplain ::env(NO_COLOR)
+
+	set code [catch {uplevel 1 $body} result]
+    }
+
+    if {$code == 1} {
+	global errorInfo errorCode
+	return -code $code -errorinfo $errorInfo -errorcode $errorCode $result
+    } else {
+	return -code $code $result
+    }
+}
+
 # Setup tuiterm.exp environment.  To be used in test-cases instead of
 # "load_lib tuiterm.exp".  Calls initialization function and schedules
 # finalization function.