[PATCH 5/5] Make gdb_test's question non-optional if specified

[Pedro Alves <pedro@palves.net>]

gdb_test supports handling scenarios where GDB asks a question before
finishing handling some command.  The full prototype of gdb_test is:

  # gdb_test COMMAND PATTERN MESSAGE QUESTION RESPONSE

However, QUESTION is a question that GDB _may_ ask, not one that GDB
_must_ ask:

 # QUESTION is a question GDB may ask in response to COMMAND, like
 #   "are you sure?"
 # RESPONSE is the response to send if QUESTION appears.

If GDB doesn't raise the question, the test still passes.

I think that this is a misfeature.  If GDB regresses and stops asking
a question, the testsuite won't notice.  So I think that if a QUESTION
is specified, gdb_test should ensure it comes out of GDB.

Running the testsuite exposed a number of tests that pass
QUESTION/RESPONSE to GDB, but no question comes out.  The previous
commits fixed them all, so this commit changes gdb_test's behavior.

A related issue is that gdb_test doesn't enforce that if you specify
QUESTION, that you also specify RESPONSE.  I.e., you should pass 1, 2,
3, or 5 arguments to gdb_test, but never 4, or more than 5.  Making
gdb_test detect bogus arguments actually regressed some testcases,
also all fixed in previous commits.

Change-Id: I47c39c9034e6a6841129312037a5ca4c5811f0db
---
 gdb/testsuite/lib/gdb.exp | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 0b242b64992..e9cbbe77fa4 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1324,9 +1324,10 @@ proc gdb_test_multiline { name args } {
 #   omitted, then the pass/fail messages use the command string as the
 #   message.  (If this is the empty string, then sometimes we don't
 #   call pass or fail at all; I don't understand this at all.)
-# QUESTION is a question GDB may ask in response to COMMAND, like
-#   "are you sure?"
-# RESPONSE is the response to send if QUESTION appears.
+# QUESTION is a question GDB should ask in response to COMMAND, like
+#   "are you sure?"  If this is specified, the test fails if GDB
+#   doesn't print the question.
+# RESPONSE is the response to send when QUESTION appears.
 #
 # Returns:
 #    1 if the test failed,
@@ -1337,6 +1338,11 @@ proc gdb_test { args } {
     global gdb_prompt
     upvar timeout timeout
 
+    # Can't have a question without a response.
+    if { [llength $args] == 4 || [llength $args] > 5 } {
+	error "Unexpected arguments: $args"
+    }
+
     if [llength $args]>2 then {
 	set message [lindex $args 2]
     } else {
@@ -1345,11 +1351,21 @@ proc gdb_test { args } {
     set command [lindex $args 0]
     set pattern [lindex $args 1]
 
+    set must_see_question 0
+    if { [llength $args] == 5 } {
+	set must_see_question 1
+	set saw_question 0
+    }
+
     set user_code {}
     lappend user_code {
 	-re "\[\r\n\]*(?:$pattern)\[\r\n\]+$gdb_prompt $" {
 	    if ![string match "" $message] then {
-		pass "$message"
+		if {$must_see_question} {
+		    gdb_assert $saw_question "$message"
+		} else {
+		    pass "$message"
+		}
             }
         }
     }
@@ -1359,6 +1375,7 @@ proc gdb_test { args } {
 	set response_string [lindex $args 4]
 	lappend user_code {
 	    -re "(${question_string})$" {
+		set saw_question 1
 		send_gdb "$response_string\n"
 		exp_continue
 	    }
-- 
2.26.2