[Bug python/11381] New: pretty print display hint struct format problems

[Bug python/11381] New: pretty print display hint struct format problems

[chrisj at rtems dot org]

A pretty print iterator with a display hint of 'struct' prints the result of the
'to_string' call when it should not or is not needed. The problem can be shown
with a pretty print iterator for the Object_Id type in RTEMS. Stripping this
type reduces it to an "unsigned long" that is a series of bit fields. The pretty
print iterator displays the bit fields in a struct format so GDB formats the
output correctly. For example:

class object_id_printer:
    """Print an object given the ID. Print using the struct display
    hint and an iterator."""

    class object_id_iterator:
        """Use an iterator for each field expanded from the id so GDB
        output is formatted correctly."""

        def __init__(self, id):
            self.id = id
            self.count = 0

        def __iter__(self):
            return self

        def next(self):
            self.count += 1
            if self.count == 1:
                return int(self.id.value())
            elif self.count == 2:
                return self.id.node()
            elif self.count == 3:
                return self.id.api()
            elif self.count == 4:
                return self.id._class()
            elif self.count == 5:
                return self.id.index()
            raise StopIteration

    def __init__(self, id):
        self.id = rtems_object_id(id)

    def to_string(self):
        return 'to_string'

    @staticmethod
    def key(i):
        if i == 0:
            return 'id'
        elif i == 1:
            return 'node'
        elif i == 2:
            return 'api'
        elif i == 3:
            return 'class'
        elif i == 4:
            return 'index'
        return 'bad'

    def children(self):
        counter = itertools.imap (self.key, itertools.count())
        return itertools.izip (counter,
                               self.object_id_iterator(self.id))

    def display_hint (self):
        return 'struct'

The output is:

(gdb) p the_semaphore->Object.id
$36 = to_string = {
  id = 436273170,
  node = 1,
  api = classic,
  class = semaphores,
  index = 18
}

Note the "to_string = " after the $36 should not be there.

Removing the "to_string" function from the class results in:

(gdb) p the_semaphore->Object.id
$4 = AttributeError: object_id_printer instance has no attribute 'to_string'
 = {
  id = 436273170,
  node = 1,
  api = classic,
  class = semaphores,
  index = 18
}

Removing this function or returning None should be allowed and result in no
related output.

-- 
           Summary: pretty print display hint struct format problems
           Product: gdb
           Version: 7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: python
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: chrisj at rtems dot org
                CC: gdb-prs at sourceware dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From pmuldoon at redhat dot com  2010-03-31 13:05 -------
What happens if you write this in your printer:

    def to_string(self):
        return ""

Does the output format ok then?



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at sourceware dot|pmuldoon at redhat dot com
                   |org                         |
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[chrisj at rtems dot org]

------- Additional Comments From chrisj at rtems dot org  2010-04-01 00:00 -------
No. The output is:

(gdb) p the_semaphore->Object.id
$36 =  = {
  id = 436273170,
  node = 1,
  api = classic,
  class = semaphores,
  index = 18
}


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From pmuldoon at redhat dot com  2010-04-01 12:51 -------
Right so if to_string() returns None, we can omit the preceding "=" then? Would
that work?

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From pmuldoon at redhat dot com  2010-04-01 16:28 -------
I'm attaching a draft patch that will allow the user to return None in to_string
and the output should be formatted correctly. This is an example of a vector
that returns None for to_string, and a deque that returns some text:

(gdb) p v
$1 =  {0x409922 "one"}
(gdb) p ddd
$2 = std::deque with 3 elements {18, 23, 7}

If this is what you want, I'll update/clean-up/add testcases to the patch and
submit it to FSF GDB.



-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From pmuldoon at redhat dot com  2010-04-01 16:29 -------
Created an attachment (id=4698)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4698&action=view)
No leading string patch


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2010-04-07 17:21 -------
$1 =  {0x409922 "one"}

A little nit -- there are two spaces between the "=" and "{" here,
but I think there should only be one.

Also the patch introduces a new global... I'm sure there is another way.

I think the idea is good though.


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From pmuldoon at redhat dot com  2010-04-07 17:27 -------
I've a rewritten patch that passes parameters around and has done away with the
global. Patch to follow

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug python/11381] pretty print display hint struct format problems

[pmuldoon at redhat dot com]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2010-04-14 12:03 -------
Subject: Bug 11381

CVSROOT:	/cvs/src
Module name:	src
Changes by:	pmuldoon@sourceware.org	2010-04-14 12:02:46

Modified files:
	gdb            : ChangeLog 
	gdb/doc        : ChangeLog gdb.texinfo 
	gdb/python     : py-prettyprint.c 
	gdb/testsuite  : ChangeLog 
	gdb/testsuite/gdb.python: py-mi.exp py-prettyprint.c 
	                          py-prettyprint.exp py-prettyprint.py 

Log message:
	2010-04-14  Phil Muldoon  <pmuldoon@redhat.com>
	
	PR python/11381
	
	* python/py-prettyprint.c (pretty_print_one_value): Test for
	Py_None.
	(print_string_repr): Test for Py_None.  Set flags accordingly.
	Return value depending on return type.
	(print_children): Take a value indicating whether data was printed
	before this function was called.  Alter output accordingly.
	(apply_val_pretty_printer): Capture return value from
	print_string_repr and pass to print_children.
	
	2010-04-14  Phil Muldoon  <pmuldoon@redhat.com>
	
	* gdb.python/py-prettyprint.py (NoStringContainerPrinter): New printer.
	* gdb.python/py-prettyprint.c: Add justchildren struct, typedefs.
	* gdb.python/py-prettyprint.exp: New test for to_string returning None.
	* gdb.python/py-mi.exp: New test for to_string returning None.
	
	2010-04-14  Phil Muldoon  <pmuldoon@redhat.com>
	
	* gdb.texinfo (Pretty Printing): Document behaviour when to_string
	returns None.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&r1=1.11612&r2=1.11613
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/doc/ChangeLog.diff?cvsroot=src&r1=1.1045&r2=1.1046
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/doc/gdb.texinfo.diff?cvsroot=src&r1=1.703&r2=1.704
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/python/py-prettyprint.c.diff?cvsroot=src&r1=1.5&r2=1.6
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/ChangeLog.diff?cvsroot=src&r1=1.2231&r2=1.2232
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.python/py-mi.exp.diff?cvsroot=src&r1=1.6&r2=1.7
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.python/py-prettyprint.c.diff?cvsroot=src&r1=1.4&r2=1.5
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.python/py-prettyprint.exp.diff?cvsroot=src&r1=1.7&r2=1.8
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.python/py-prettyprint.py.diff?cvsroot=src&r1=1.5&r2=1.6


------- Additional Comments From pmuldoon at redhat dot com  2010-04-14 12:38 -------
Fixed as show in comment #8

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|7.1                         |7.2


http://sourceware.org/bugzilla/show_bug.cgi?id=11381

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.