[Bug gdb/10584] New: MI vars with Python pretty-printers don't get updated

[Bug gdb/10584] New: MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

Hello,

If I create a Python pretty-printer, it doesn't get updated in GUI using gdb.
This is because the MI var doesn't get updated. To recreate:

Download bug.c, bug.py which I will attach in a minute.
> gcc -g bug.c
> gdb --int mi2
(gdb) python execfile("bug.py") # Install pretty-printer for type "MyInt"
(gdb) break main
(gdb) run
(gdb) next # do x = 3
(gdb) -var-create x * x
(gdb) next # x = 5
(gdb) -var-update * # Doesn't report x changing.

This was tested on a current CVS: 6.8.50.20090831

Thanks,
Noam

-- 
           Summary: MI vars with Python pretty-printers don't get updated
           Product: gdb
           Version: 6.8
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: noamraph at gmail dot com
                CC: gdb-prs at sourceware dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=10584

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-01 08:16 -------
Created an attachment (id=4162)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4162&action=view)
C Source needed to recreate the bug


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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-01 08:17 -------
Created an attachment (id=4163)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4163&action=view)
Python source needed to recreate the bug


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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-01 09:12 -------
Ok, here's a workaround/half-fix:

Apply the patch. It simply comments out two lines which avoid updating a value
which has a pretty printer and for which -var-list-children was not called.
Python pretty-printers get updated without calling -var-list-children - the
attached bug.py is an example.

Now, use bug-workaround.py instead of bug.py. It seems that gdb doesn't update
the value before getting its string. bug-workaround.py references and
dereferences the value, with the effect of re-evaluating it.

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-01 09:13 -------
Created an attachment (id=4165)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4165&action=view)
Patch to half-fix the bug


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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-01 09:14 -------
Created an attachment (id=4166)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4166&action=view)
Workaround which works when the patch is applied


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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2009-09-01 16:06 -------
This code has been extensively reworked on the python branch in
the archer repository.  We've also discussed the design quite a bit
on the archer and gdb lists.
If you could try that branch, it would help.
We'll be pushing this code into CVS as soon as we all agree it is ready.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at redhat dot com


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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-03 07:45 -------
I just checked it with the archer-tromey-python branch, and it works with no
workarounds needed!

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=10584

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-03 13:26 -------
Sorry, I was mistaken. The variable was updated because the pretty-printer
wasn't used at all...

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|FIXED                       |


http://sourceware.org/bugzilla/show_bug.cgi?id=10584

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[noamraph at gmail dot com]

------- Additional Comments From noamraph at gmail dot com  2009-09-03 13:37 -------
Ok. If I do -enable-pretty-printing (in the python branch), we return to the
original bug - even bug-workaround doesn't work. :-(

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2009-09-03 16:15 -------
I'm looking at it.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at sourceware dot|tromey at redhat dot com
                   |org                         |
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-09-03 16:15:35
               date|                            |


http://sourceware.org/bugzilla/show_bug.cgi?id=10584

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[Bug gdb/10584] MI vars with Python pretty-printers don't get updated

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2009-09-03 18:14 -------
I fixed this on the archer-tromey-python branch.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|6.8                         |6.9


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