[Pkg-electronics-devel] Bug#1085383: libngspice0 should depends ngspice in the same version

[Robert Paciorek]

Hi Carsten,

thanks for reply!

On 2024-10-18 20:34:26 Carsten Schoenert wrote:
> Hello Robert,
> 
> Am Fri, Oct 18, 2024 at 05:41:44PM +0000 schrieb Robert Paciorek:
>  
> > libngspice uses configuration and model files provided by ngspice
> > package (/usr/share/ngspice/scripts/spinit and
> > /usr/lib/x86_64-linux-gnu/ngspice/*.cm).  
> 
> I disagree, the libngsice0 package is only containing the shared
> libray parts and if the libary would use some external things without
> depending on it would be programmed in a bad way.

These files are part of the official library archives from
sourceforge.net
(https://sourceforge.net/projects/ngspice/files/ng-spice-rework/43/ngspice-43_dll_64.7z).

> > * running software used libngspice0 without ngspice installed may
> > results in error "MIF-ERROR - unable to find definition of model
> > and Simulation interrupted due to error!" (with previous warning
> > "Warning: can't find the initialization file spinit")  
> 
> The ngspice binary isn't even depending on any symbol from libngspice
> libary so dpkg-shlibdeps isn't filling in the library as an
> dependency.
> 
> https://packages.debian.org/unstable/ngspice

Yes, ngspice is not depending on symbols from libngspice.

It is libngspice that (in some scenarios) uses files provided only with
ngspice package (perhaps they should be in a separate package, e.g.
ngspice-data, because they are used also by the ngspice executable).

> If there is a symbol from there needed then this needs to get fixed
> upstream. But I'm sure this isn't the case here. Maybe Holger (CCed)
> can give a better explanation.
> 
> > * running software used libngspice0 with installed ngspice in
> > version different than libngspice0 version (for example libngspice0
> > 43+ds-1~bpo12+1 and ngspice 39.3+ds-1) may cause segmentation
> > fault.  
> 
> You do not provide an example where we could prove your assumption.
> Without it's impossible to re-adjust a potential misbehavior.
> 
> > Segmentation fault occurs only while referring to standard models
> > provided by *.cm files, for example while simulating digital
> > systems using:
> > 
> > A1 [in1 in2] out AND
> > .model AND d_and  
> 
> You might provide what you try to do in detail, Holger can then have a
> look at this.

I'm attaching the source code of simple program used libngspice
(gdspice.cpp) and two netlist files:
- digital.netlist - simple digital circuit (used standard ngspice model
  for AND gate via `.model` command)
- analog.netlist - similar (but analog, without `.model` command)
  circuit

`gdspice.cpp` can load libngspice via dlopen (default, build via `g++
gdspice.cpp`) or can be linked with libngspice on build time (unset
USE_DLOPEN macro and build via `g++ gdspice-nogodot.cpp -lngspice`).

This allow test all 3 scenarios:

1. The same version (43+ds-1~bpo12+1) of libngspice0 and ngspice
   packages:
   -> both circuit are simulated.
2. Installed only libngspice0 (still 43+ds-1~bpo12+1, but ngspice is not
   installed):
   -> analog circuit produce warning about spinit, but is simulated,
   -> digital circuit produce error about missed definition of model
   and is not simulated.
3. Different version of libngspice0 (43+ds-1~bpo12+1) and ngspice
   (39.3+ds-1):
   -> analog circuit is simulated (no warning),
   -> digital circuit cause segmentation fault inside libngspice0.

Using strace shows that *.cm files are opened even though they are not
referenced in the program source code (they are used internally by the
library, due to content of the default `spinit` file, also internally
referenced via libngspice).

Regards
Robert

> Holger, I assume you are interested in some samples so you could have
> a look at? Thanks!
> 
> Regards
> Carsten
> 

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