[gdb/testsuite] Fix gdb.base/readline.exp with stub-termcap

When doing a build which uses stub-termcap, we run into:
...
(gdb) set width 7
<b) FAIL: gdb.base/readline.exp: set width 7 (timeout)
...

Since readline can't detect very basic terminal support, it falls back on
horizontal scrolling.

Fix this by detecting the horizontal scrolling case, and skipping the
subsequent test.

Tested on x86_64-linux.

PR testsuite/30400
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30400

diff --git a/gdb/testsuite/gdb.base/readline.exp b/gdb/testsuite/gdb.base/readline.exp
index 87225273c251385c47aa5a528f93de455b4016a4..e00ed088282e90ae2998267b9a66d946bf01dce4 100644 (file)
--- a/gdb/testsuite/gdb.base/readline.exp
+++ b/gdb/testsuite/gdb.base/readline.exp
@@ -219,31 +219,44 @@ save_vars { env(TERM) } {
        set char_total 4500
        set char_sent 0
 
-       # Adjust the terminal width.
-       gdb_test_no_output "set width 7"
-
-       # Send the command prefix, then lots of additional characters
-       # that create a really long command that wraps over multiple
-       # lines.
-       send_gdb "help X"
-       gdb_test_multiple "" "send long command to GDB" {
-           -re "X" {
-               incr char_sent
-               if {$char_sent <= $char_total} {
-                   send_gdb "X"
-                   exp_continue
-               }
+       # Adjust the terminal width.  Detect horizontal scrolling, which
+       # happens with stub-termcap.c.
+       set horizontal_scrolling 0
+       set cmd "set width 7"
+       gdb_test_multiple $cmd "" {
+           -re "^$cmd\r\n$gdb_prompt $" {
+               pass $gdb_test_name
            }
-           -re "\[ \b\r\n\]" {
-               exp_continue
+           -re "^$cmd\r\n<b\\) $" {
+               set horizontal_scrolling 1
+               pass $gdb_test_name
            }
        }
 
-       # Send the final newline so that GDB will process the command.
-       # Check GDB returns a suitable error.
-       send_gdb "\n"
-       gdb_test "" \
-           "Undefined command: \"X+\"\\.  Try \"help\"\\." \
-           "All the characters transferred"
+       if { !$horizontal_scrolling } {
+           # Send the command prefix, then lots of additional characters
+           # that create a really long command that wraps over multiple
+           # lines.
+           send_gdb "help X"
+           gdb_test_multiple "" "send long command to GDB" {
+               -re "X" {
+                   incr char_sent
+                   if {$char_sent <= $char_total} {
+                       send_gdb "X"
+                       exp_continue
+                   }
+               }
+               -re "\[ \b\r\n\]" {
+                   exp_continue
+               }
+           }
+
+           # Send the final newline so that GDB will process the command.
+           # Check GDB returns a suitable error.
+           send_gdb "\n"
+           gdb_test "" \
+               "Undefined command: \"X+\"\\.  Try \"help\"\\." \
+               "All the characters transferred"
+       }
     }
 }