[binutils-gdb] gdb/testsuite: Remove interactive prompt case from mi_gdb_test

[Andrew Burgess <aburgess at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d820d0c37beda1c29ff50bb1f2ebc1d23114d735

commit d820d0c37beda1c29ff50bb1f2ebc1d23114d735
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date:   Thu Jan 3 21:13:52 2019 +0000

    gdb/testsuite: Remove interactive prompt case from mi_gdb_test
    
    I noticed that when running this test:
    
      make check-gdb RUNTESTFLAGS="--target_board=native-gdbserver gdb.mi/mi-break.exp"
    
    I would occasionally see some UNRESOLVED test results like this:
    
      (gdb)
      PASS: gdb.mi/mi-break.exp: mi-mode=separate: breakpoint at main
      Expecting: ^(kill[
      ]+)?(.*[
      ]+[(]gdb[)]
      [ ]*)
      kill
      &"kill\n"
      ~"Kill the program being debugged? (y or n) [answered Y; input not from terminal]\n"
      =thread-group-exited,id="i1"
      ERROR: Got interactive prompt.
      UNRESOLVED: gdb.mi/mi-break.exp: mi-mode=separate:
    
    The problem appears to be that the expect buffer fills up to include
    the '(y or n)' prompt without including the following lines.
    
    The pattern supplied by the outer test script is looking for the
    following lines.  As the following lines are not present then expect
    matches on the interactive prompt case rather than the case for the
    user supplied pattern.
    
    The problem with this is that we are not really at an interactive
    prompt, GDB is providing an answer for us and then moving on.  When I
    examine a successful run of the test the output from GDB is identical,
    the only difference is where expect happens to buffer the output from
    GDB.
    
    This patch remove all special handling of the interactive prompt
    case.  This means that if we ever break GDB and start seeing an
    unexpected interactive prompt then tests will rely on a timeout to
    fail, instead of having dedicated interactive prompt detection, but
    this solves the problem that an auto-answered prompt looks very
    similar to an interactive prompt.
    
    With this patch in place I can now leave the following loop running
    indefinitely, where before it would fail usually after ~10
    iterations.
    
      while make check-gdb RUNTESTFLAGS="--target_board=native-gdbserver gdb.mi/mi-break.exp"; \
      do /bin/true; \
      done
    
    gdb/testsuite/ChangeLog:
    
    	* lib/mi-support.exp (mi_gdb_test): Remove interactive prompt
    	case.

Diff:
---
 gdb/testsuite/ChangeLog          | 5 +++++
 gdb/testsuite/lib/mi-support.exp | 5 -----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 3f7d72c..309cfb5 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-09  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* lib/mi-support.exp (mi_gdb_test): Remove interactive prompt
+	case.
+
 2019-01-06  Tom Tromey  <tom@tromey.com>
 
 	PR gdb/28155:
diff --git a/gdb/testsuite/lib/mi-support.exp b/gdb/testsuite/lib/mi-support.exp
index d193592..a58c4f6 100644
--- a/gdb/testsuite/lib/mi-support.exp
+++ b/gdb/testsuite/lib/mi-support.exp
@@ -833,11 +833,6 @@ proc mi_gdb_test { args } {
 	    perror "Window too small."
 	     fail "$message"
 	}
-	 -re "\\(y or n\\) " {
-	    send_gdb "n\n"
-	    perror "Got interactive prompt."
-	     fail "$message"
-	}
 	 eof {
 	     perror "Process no longer exists"
 	     if { $message != "" } {