[PATCH] PR cli/21688: Fix multi-line/inline command differentiation

Sergio Durigan Junior
2017-06-29T02:05:44Z

This bug is a regression caused by the following commit:

604c4576fdcfc4e7c28f569b3748a1b6b4e0dbd4 is the first bad commit
commit 604c4576fdcfc4e7c28f569b3748a1b6b4e0dbd4
Author: Jerome Guitton <guitton@adacore.com>
Date: Tue Jan 10 15:15:53 2017 +0100

The problem happens because, on cli/cli-script.c:process_next_line,
GDB is not using the command line string to identify which command to
run, but it instead using the 'struct cmd_list_element *' that is
obtained by using the mentioned string. The problem with that is that
the 'struct cmd_list_element *' doesn't have any information on
whether the command issued by the user is a multi-line or inline one.

A multi-line command is a command that will necessarily be composed of
more than 1 line. For example:

(gdb) if 1
>python
>print ('hello')
>end
>end

As can be seen in the example above, the 'python' command actually
"opens" a new command line (represented by the change in the
indentation) that will then be used to enter Python code. OTOH, an
inline command is a command that is "self-contained" in a single line,
for example:

(gdb) if 1
>python print ('hello')
>end

This Python command is a one-liner, and therefore there is no other
Python code that can be entered for this same block. There is also no
change in the indentation.

So, the fix is somewhat simple: we have to revert the change and use
the full command line string passed to process_next_line in order to
identify whether we're dealing with a multi-line or an inline command.
This commit does just that. As can be seen, this regression also
affects other languages, like guile or the compile framework. To make
things clearer, I decided to create a new helper function responsible
for identifying a non-inline command.

Testcase is attached.

gdb/ChangeLog:
2017-06-29 Sergio Durigan Junior <sergiodj@redhat.com>

PR cli/21688
* cli/cli-script.c (command_name_equals_not_inline): New function.
(process_next_line): Adjust 'if' clauses for "python", "compile"
and "guile" to use command_name_equals_not_inline.

gdb/testsuite/ChangeLog:
2017-06-29 Sergio Durigan Junior <sergiodj@redhat.com>

PR cli/21688
* gdb.python/py-cmd.exp (test_pr21688): New procedure. Call it.
---
gdb/ChangeLog | 7 +++++++
gdb/cli/cli-script.c | 21 +++++++++++++++++----
gdb/testsuite/ChangeLog | 5 +++++
gdb/testsuite/gdb.python/py-cmd.exp | 30 ++++++++++++++++++++++++++++++
4 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a82026f..194cda8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2017-06-29 Sergio Durigan Junior <sergiodj@redhat.com>
+
+ PR cli/21688
+ * cli/cli-script.c (command_name_equals_not_inline): New function.
+ (process_next_line): Adjust 'if' clauses for "python", "compile"
+ and "guile" to use command_name_equals_not_inline.
+
2017-06-28 Pedro Alves <palves@redhat.com>

* command.h: Include "common/scoped_restore.h".
diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index e0e27ef..72f316f 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -900,6 +900,20 @@ command_name_equals (struct cmd_list_element *cmd, const char *name)
&& strcmp (cmd->name, name) == 0);
}

+/* Return true if NAME is the only command between COMMAND_START and
+ COMMAND_END. This is useful when we want to know whether the
+ command is inline (i.e., has arguments like 'python command1') or
+ is the start of a multi-line command block. */
+
+static bool
+command_name_equals_not_inline (const char *command_start,
+ const char *command_end,
+ const char *name)
+{
+ return (command_end - command_start == strlen (name)
+ && startswith (command_start, name));
+}
+
/* Given an input line P, skip the command and return a pointer to the
first argument. */

@@ -997,21 +1011,20 @@ process_next_line (char *p, struct command_line **command, int parse_commands,
{
*command = build_command_line (commands_control, line_first_arg (p));
}
- else if (command_name_equals (cmd, "python"))
+ else if (command_name_equals_not_inline (p_start, p_end, "python"))
{
/* Note that we ignore the inline "python command" form
here. */
*command = build_command_line (python_control, "");
}
- else if (command_name_equals (cmd, "compile"))
+ else if (command_name_equals_not_inline (p_start, p_end, "compile"))
{
/* Note that we ignore the inline "compile command" form
here. */
*command = build_command_line (compile_control, "");
(*command)->control_u.compile.scope = COMPILE_I_INVALID_SCOPE;
}
-
- else if (command_name_equals (cmd, "guile"))
+ else if (command_name_equals_not_inline (p_start, p_end, "guile"))
{
/* Note that we ignore the inline "guile command" form here. */
*command = build_command_line (guile_control, "");
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b7462a5..ef46a5d 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-29 Sergio Durigan Junior <sergiodj@redhat.com>
+
+ PR cli/21688
+ * gdb.python/py-cmd.exp (test_pr21688): New procedure. Call it.
+
2017-06-28 Doug Gilmore <Doug.Gilmore@imgtec.com>

PR gdb/21337
diff --git a/gdb/testsuite/gdb.python/py-cmd.exp b/gdb/testsuite/gdb.python/py-cmd.exp
index 2dbf23ce..052afa4 100644
--- a/gdb/testsuite/gdb.python/py-cmd.exp
+++ b/gdb/testsuite/gdb.python/py-cmd.exp
@@ -181,6 +181,36 @@ gdb_test "complete expr_test bar\." \
"expr_test bar\.bc.*expr_test bar\.ij.*" \
"test completion through complete command"

+# Testing PR cli/21688. This is not language-specific, but the
+# easiest way is just to test with Python.
+proc test_pr21688 { } {
+ set define_cmd_not_inline {
+ { "if 1" " >$" }
+ { "python" " >$" }
+ { "print ('hello')" " >$" }
+ { "end" " >$" }
+ { "end" "hello\r\n" } }
+
+ set define_cmd_inline {
+ { "if 1" " >$" }
+ { "python print ('hello')" " >$" }
+ { "end" "hello\r\n" } }
+
+ foreach t [list $define_cmd_not_inline $define_cmd_inline] {
+ foreach l $t {
+ foreach { command regex } $l {
+ gdb_test_multiple "$command" "$command" {
+ -re "$regex" {
+ pass "$command"
+ }
+ }
+ }
+ }
+ }
+}
+
+test_pr21688
+
if { [readline_is_used] } {
set test "complete 'expr_test bar.i'"
send_gdb "expr_test bar\.i\t\t"
--
2.9.3