gdb_test_multiple: Anchor prompt match if -lbl
The testcase added by this patch has a gdb_test_multiple call that
wants to match different lines of output that all have a common
prefix, and do different actions on each. Instead of a single regular
expression with alternatives, it's clearer code if the different
expressions are handled with different "-re", like so:
gdb_test_multiple "command" "" -lbl {
-re "^command(?=\r\n)" {
exp_continue
}
-re "^\r\nprefix foo(?=\r\n)" {
# Some action for "foo".
exp_continue
}
-re "^\r\nprefix bar(?=\r\n)" {
# Some action for "bar".
exp_continue
}
-re "^\r\nprefix \[^\r\n\]*(?=\r\n)" {
# Some action for all others.
exp_continue
}
-re "^\r\n$::gdb_prompt $" {
gdb_assert {$all_prefixes_were_seen} $gdb_test_name
}
}
Above, the leading anchors in the "^\r\nprefix..." matches are needed
to avoid too-eager matching due to the common prefix. Without the
anchors, if the expect output buffer happens to contain at least:
"\r\nprefix xxx\r\nprefix foo\r\n"
... then the "prefix foo" pattern match inadvertently consumes the
first "prefix xxx" line.
Without the anchor in the prompt match, like:
-re "\r\n$::gdb_prompt $" {
gdb_assert {$all_prefixes_were_seen} $gdb_test_name
}
Or the equivalent:
-re -wrap "" {
gdb_assert {$all_prefixes_were_seen} $gdb_test_name
}
... then if the expect buffer contains:
"\r\nmeant-to-be-matched-by-lbl\r\nprefix foo\r\n$gdb_prompt "
... then the prompt regexp matches this, consuming the "prefix" line
inadvertently, and we get a FAIL. The built-in regexp matcher for
-lbl doesn't get a chance to match the
"\r\nmeant-to-be-matched-by-lbl\r\n" part, because the built-in prompt
match appears first within gdb_test_multiple.
By adding the anchor to the prompt regexp, we avoid that problem.
However, the same expect output buffer contents will still match the
built-in prompt regexp. That is what is fixed by this patch. It
makes it so that if -lbl is specified, the built-in prompt regexp has
a leading anchor.
Original idea for turning this into a gdb.testsuite/ testcase by Tom
de Vries <tdevries@suse.de>.
Approved-By: Tom de Vries <tdevries@suse.de>
Change-Id: Ic2571ec793d856a89ee0d533ec363e2ac6036ea2
3 files changed
