[mkgmap-dev] How to solve/debug weird problem

Wed Jan 19 20:41:54 GMT 2011

Hallo Johannes,

while I cannot help with the actual bug, I can give you some advice to 
narrow it down. Once you have a minimal test case, your bug should be 
fixable.

On Tue, Jan 18, 2011 at 09:52:13PM +0100, Johannes Formann wrote:
>rerun with a reduced option set (an the debug-patch still active):
>    [apply] Executing 'java' with arguments:
>'-Xms256m'
>'-Xmx2560m'
>'-ea'
>'-jar'
>'mkgmap.jar'
>'--max-jobs=1'
>'--style-file=radkarte'

Does the problem disappear if you remove --style-file (i.e., use the 
default style)?

>'--overview-mapnumber=59420000'
>'--overview-mapname=59420000'
>'--series-name=OSM_Radkarte'
>'--product-id=1'
>'--family-id=5942'
>'--family-name=OSM Radkarte 18.01.2011'
>'--country-name=Deutschland'
>'--country-abbr=DE'

My educated guess is that these should not matter at all (please confirm 
by trying to removing these).

>'--latin1'
>'--code-page=1252'
>'--add-pois-to-areas'
>'--adjust-turn-headings'
>'--drive-on-right'
>'--check-roundabouts'
>'--remove-short-arcs=3.3''--net''--route'
>'--gmapsupp''--tdbfile''--index'
>'M0001736.TYP''-c''/home/osm/build/template.args'

What is in template.args? Any options before the file name 
59420059.osm.gz?

>But got an Exception again.
>
>    [apply] SEVERE (MapSplitter): /home/osm/build/59420059.osm.gz: ...

What if you replace these last bits

>'--gmapsupp''--tdbfile''--index'
>'M0001736.TYP''-c''/home/osm/build/template.args'

with just /home/osm/build/59420059.osm.gz

That should speed up the crash, shouldn't it? Please save that 
problematic tile file somewhere, so that you can test patches with the 
exact same input.

The faster the command runs, the easier you can test different options 
until you find the minimal options that are needed to trigger the bug.

You might also want to drop definitions from your style file until the 
crash goes away. But I would first try to reduce the other command line 
options before touching the --style-file option or the style 
definitions.

Another way of reducing would be to load the tile file in a powerful 
text editor and drop half the relations (or all of them if the crash 
persists), then drop half the ways, and so on, until the crash goes 
away. That would lead to a minimal test case. But I guess that Steve or 
WanMil can do that sort of processing if you make the file available to 
them. But, first try to narrow down the options and the style definition.

Best regards,

	Marko