Author: LessTif Core Team
Description: Reporting Bugs within LessTif
Keywords: LessTif, Bugs, Pathes, Bug Report

# Reporting Bugs and Submitting Fixes

## Table of Contents

- Introduction
- What you'll need to find bugs
- Recommended reading
- Isolating bugs
- X Protocol Errors
- Submitting bug reports
- Submitting patches
- Where to send bug reports and fixes

## Introduction

Bug hunting in LessTif isn't really all that different from bug hunting in arbitrary X application code, with a few notable exceptions.

We encourage users to help us make LessTif a better product by doing some preliminary ground-work for the developers when you find a bug in the library. Of course, what we really want is a patch that fixes the bug, but we'll settle for some help.

## What you'll need

Let's see:

- a computer (Ta-dah!)
- the X Window System, at release level R5 or above
- a compiler/assembler/linker
- a debugger
- some test code

Of course, if you don't have that, you probably don't need to read this, do you?

## Recommended Reading

First of all you should check our own tutorial on Bug Hunting! It explains in detail the built-in debugging facilities within the LessTif libraries.

The following list of books are nice to have, especially the Intrinsics and the Motif books, but you can probably get away without them if you have a full set of man pages.

One thing, though: if you want to understand what widget methods do, and how a widget works, they are an absolute necessity.

The O'Reilly books "The Definitive Guide to the X Window System". Of these, you'll want:

- Volume 1: Xlib Programming Manual
- Volume 2: Xlib Reference Manual
- Volume 4: X Toolkit Intrinsics Programming Manual
- Volume 5: X Toolkit Intrinsics Reference Manual
- Volume 6A: Motif Programming Manual
- Volume 6B: Motif Reference Manual

If you have R6 (Linux, *BSD, others), you'll want:

- Programmer's Supplement for Release 6

From the OSF, you'll want

- OSF/Motif Programmer's Reference (for 1.2)
- OSF/Motif Programmer's Guide (for 1.2)

The style guide is nice, but not required.

Further details on debugging X11 apps can be found at these writings:

- www.openmotif.org/tnt/#Debug_Breakpoints
- www.rahul.net/kenton/perrors.html

## Isolating bugs

Ok, your favorite Motif program is barfing on LessTif, and you're so inclined to help us fix the problem. Problems generally fall into four broad categories:

- Behavior
- Visual
- X Protocol Error
- Core dump

Of these, the first two are more trivial, and (as of now, anyway) are allocated somewhat lower priority, while we work on implementing *missing* behaviors. X Errors and core dumps have a higher priority.

One thing to keep in mind is that the location that the problem occurs in not necessarily the same as the location that caused the problem; this is due to the (normally) asynchronous nature of X applications. When your application has a problem, the first thing to do is run the application synchronously, to see if the location of the error changes (you'll be surprised how often it will). Here's how to do it with gdb:

    root@zeek:/var/root/lesstif/testXm/filesb# gdb ./test1
    GDB is free software and you are welcome to distribute copies of it
     under certain conditions; type "show copying" to see the conditions.
    There is absolutely no warranty for GDB; type "show warranty" for details.
    GDB 4.14 (i586-unknown-linux), Copyright 1995 Free Software Foundation, Inc...
    (no debugging symbols found)...
    (gdb) run -sync
    Starting program: /var/root/lesstif/testXm/filesb/./test1 -sync

It'll probably spit out a bunch of debug messages (especially if you set the DEBUG_SOURCES environment variable). Note that the commands passed to the run command are actually command line arguments to the program.

On some systems, you may find that you can't set breakpoints at the start if you use shared libraries. That's because the symbols won't be resolved until a process image exists. To work around this, set a breakpoint at `main()`, and run. Once the breakpoint at main is reached, you'll find that you can set the other breakpoints.

Once you've had your program dump core, just say "where". This also works if your program just crashed when not running within a debugger but it created a core dump. Then just start
`gdb program core`
and type "where".
Again from gdb:

    Program received signal SIGSEGV, Segmentation fault.
    0x40076918 in __XmStringGetNextComponent (context=0x8081de0) at XmString.c:68
    68          if (context->current_segment < context->string->number_of_segments)
    (gdb) where
    #0  0x40076918 in __XmStringGetNextComponent (context=0x8081de0)
        at XmString.c:68
    #1  0x40077ea7 in XmStringGetLtoR (string=0x30,
        tag=0x804dc68 "FONTLIST_DEFAULT_TAG_STRING", text=0xbffffa00)
        at XmString.c:869
    #2  0x8049793 in cb (w=0x8062c00, a=0x0, b=0xbffffa64) at test1.c:32
    #3  0x400aa718 in XtCallCallbackList ()
    #4  0x4005e7f0 in _XmSbButton (w=0x806cb00, client=0x0, call=0xbffffac0)
        at SelectionBox.c:467
    #5  0x400aa743 in XtCallCallbackList ()
    #6  0x4004e5a0 in Activate (w=0x806cb00, event=0xbffffce4, params=0x0,
        num_params=0x0) at PushBG.c:1014
    #7  0x4004f10b in input_dispatch (gadget=0x806cb00, event=0xbffffce4,
        event_mask=64) at PushBG.c:1360
    #8  0x40035ad6 in _XmDispatchGadgetInput (w=0x806cb00, event=0xbffffce4,
        mask=64) at GadgetUtil.c:205
    #9  0x40045492 in _XmGadgetActivate (w=0x8062c00, event=0xbffffce4,
        params=0x0, num_params=0x8059668) at Manager.c:795
    #10 0x400d2ceb in HandleActions ()
    #11 0x400d35ae in HandleComplexState ()
    #12 0x400d365b in _XtTranslateEvent ()
    #13 0x400b412f in XtDispatchEventToWidget ()
    #14 0x400b4aa9 in _XtDefaultDispatcher ()
    ---Type <return> to continue, or q <return> to quit---
    #15 0x400b4ce3 in XtDispatchEvent ()
    #16 0x400b4fd9 in XtAppMainLoop ()
    #17 0x80498f1 in main (argc=1, argv=0xbffffd78) at test1.c:69
    #18 0x80495a4 in ___crt_dummy__ ()

Note the line numbers. Please do NOT send a trace without having compiled with debug (the -g option).

## About X Protocol Errors

Sometimes the program will fail with:

    X Error: Bad Drawable
      (other stuff)

or something similar. This is a problem with something that got sent to the X server.

This isn't hard to track down if you've run in synchronous mode. Just set a breakpoint at the exit() function, run with the -sync option, and you'll get a trace from the point where the error occurred, plus some other information. These are crucial to proper LessTif functionality -- these must be stamped out.

## Submitting bug reports

When (not if) you find a problem with LessTif, we really want to know. In first place we need a detailed description of the problem and you specific system. Try to be as complete as you can - if you send just a description like
Well, I ran an app, and the thingie at the bottom of the wossname didn't look right
you are in all likelihood going to be ignored.

On the application side specify which program version (including a reference where to get it if it's a "free" application) and how to reproduce the bug. Sometimes one will ran into non-reproducible ones. You should also report them, but due to their somewhat obscure nature they're hard to track down perhaps. Further we need details about the version of LessTif you have installed. These include:

- version number
- distribution (a binary package, or did you build from sources)
- if being built from sources the configuration options may be of interest

Finally we need to know about your system: which hardware platform (no details about specific hardware, but name the CPU architecture) and which operating system. On un*x `uname -a` gives helpful information.

Ideally, a patch is what we would prefer to receive. Failing that, we need sample code, and a stack trace of the problem (even if it was an X Error). If it was a behavioral or visual problem, just a description will do, although some code that exhibits the behavior would be nice.

We also need the version number of the file that had the problem. If you prefer, and you are using lesstif-current, you can tell us the date you noticed the problem. Please do not tell us the problem two months after you saw it, the code base changes too rapidly for us to be able to make anything meaningful out of a bug report that old.

## Submitting patches

Patches are the preferred form of bug report, as it lessens our efforts to track down where the bugs are. If you do submit a patch, please try to keep a few rules in mind.
First the most important ones:

- Explain what the changes should do and why they improve things!
- Always create patches against the latest official source release or even our code as in our public CVS repository!
- Specify exactly against which version of the code the diff was created!
- We can only accept patches in the "unified diff" format (with GNU diff, this is "diff -u"). If you want to, you can send a "context diff" ("diff -c").
- Always ensure that the code still builds and links completly (use dependency tracking or "make clean" to be sure). Also the resulting binary should still work, and even better then before, so please run more than one test only!
  A good idea is to run our examples within our test/ tree.

Some more things to consider:

- When writing your fix, please try to follow the coding style of the file you are fixing. We are currently debating coding standards, so expect to see one soon.
- Try not to submit a fix that creates dead code. Using "#if 0" or commented code is discouraged. We can do that (because, after all, we are the elitist core team;), but you are discouraged from that, because it makes the patches hard to read.
- Do not be discouraged if your patch is not accepted verbatim. Often people submit patches that one or more of the core team will recognize as identifying a problem, but the core member will recognize that your fix will break some other piece of functionality. We'll try to tell you, but we're human, so we may forget.
- Remember that relay mailers are free to alter the content of text messages, and often do so. Lines should always be less than 80 characters in length.
- If you are working on a non-un*x platform take care of the different text format (e.g. <carriage-return><line-feed> vs. <line-feed> on DOS-related platforms)!

## Where to send bug reports and fixes

We have a working bugs database at SourceForge.net !
You may add bugs by using http://sourceforge.net/tracker/?atid=108596&group_id=8596.

Patches can be sent to our mailinglist if they are quite small. If they are big you should ask first where to send them. Patches of any size are also accepted (probably the best method) on our Patch Manager at http://sourceforge.net/tracker/?atid=308596&group_id=8596&func=browse.

Thanks, and remember:
All help is appreciated!