Netclass clearance resetting to zero

[Chris Pavlina]

Uh... I'm not really sure what's causing this, and I'm sorry to say I don't really have enough time to investigate well enough to file a _proper_ bug report... but running latest master (and first noticed a few days ago, so at least a few commits old), something keeps resetting my netclass clearance to zero. Not sure what's triggering this, but I'm noticing suddenly every few hours that pcbnew lets me route traces directly touching, check design rules and clearance is zero!

Application: kicad
Version: (2017-08-17 revision 667d32c4a)-master, debug build
Libraries: wxWidgets 3.0.3
           libcurl/7.54.1 OpenSSL/1.1.0f zlib/1.2.11 libpsl/0.17.0 (+libicu/59.1) libssh2/1.8.0 nghttp2/1.23.1
Platform: Linux 4.12.4-1-ARCH x86_64, 64 bit, Little endian, wxGTK
- Build Info -
wxWidgets: 3.0.3 (wchar_t,wx containers,compatible with 2.8)
Boost: 1.64.0
Curl: 7.54.1
KiCad - Compiler: GCC 7.1.1 with C++ ABI 1011
        Settings: USE_WX_GRAPHICS_CONTEXT=OFF
                  USE_WX_OVERLAY=OFF
                  KICAD_SCRIPTING=ON
                  KICAD_SCRIPTING_MODULES=ON
                  KICAD_SCRIPTING_WXPYTHON=ON
                  KICAD_SCRIPTING_ACTION_MENU=OFF
                  BUILD_GITHUB_PLUGIN=ON
                  KICAD_USE_OCE=ON

[Wayne Stambaugh (stambaughw)]

I thought I had inadvertently did something wrong yesterday while laying out a board but apparently this is a legitimate issue.

[Nicholas Savenlid (nicholas-z)]

also did hit me in 2017-aug-18 release but i did not at the time understand it was a bug, i assumed it was my fault.

that 2017-aug-18 nigthly is scary

[Marcos Chaparro (nitrousnrg)]

I think this bug is fixed in latest nighty

[Michael Geselbracht (mgeselbracht)]

No, the bug is still there and easy to reproduce:

1. In Pcbnew set a clearance >0 in "Design Rules"->Clearance for the default netclass
2. Open the footprint editor -> Clearance is set to zero in Pcbnew.

This is done in pcbnew/modulframe.cpp:244 ff :

244 SetBoard( new BOARD() );
245 // In modedit, the default net clearance is not known.
246 // (it depends on the actual board)
247 // So we do not show the default clearance, by setting it to 0
248 // The footprint or pad specific clearance will be shown
249 GetBoard()->GetDesignSettings().GetDefault()->SetClearance( 0 );

In line 249 the global defaults object is returned and its clearance attribute set to zero.

[Michael Geselbracht (mgeselbracht)]

It is a regression introduced with commit 75cda5021d. Since then there is a global default NETCLASS object shared by all BOARD instances.

[Maciej Suminski (orsonmmz)]

Michael, thank you for such accurate investigation - it was really helpful.

[Michael Geselbracht (mgeselbracht)]

I'm glad that I could help. Thank you for the fix.