Label with origin at a location where wires cross over will get assigned to both nets

[Kyle]

KiCad version: v4.0.4 using community Arch Linux packages.

## Problem Description

If two wires cross over each other without a junction, the wires remain unconnected as expected.

If a label is placed with its origin at the location where the wires cross over, then both nets are assigned the net name by the label.

ERC does not catch this.

## Expected behavior

ERC error indicating an ambiguous label assignment. If intentional, add a junction at the intersection. If unintentional, shift the label or wires one position.

## Links

Imgur Album of Schematic and Layout: http://imgur.com/a/paOpf

KiCad project to recreate: https://github.com/kylemanna/kicad-netlist-headache

Long winded blog post for more detail: https://blog.kylemanna.com/kicad-schematic-label-breaks-netlist

## Version information

Application: kicad
Version: 4.0.4-stable release build
wxWidgets: Version 3.0.2 (debug,wchar_t,compiler with C++ ABI 1010,GCC 6.2.1,wx containers,compatible with 2.8)
Platform: Linux 4.8.4-1-ARCH x86_64, 64 bit, Little endian, wxGTK
Boost version: 1.62.0
         USE_WX_GRAPHICS_CONTEXT=OFF
         USE_WX_OVERLAY=OFF
         KICAD_SCRIPTING=ON
         KICAD_SCRIPTING_MODULES=ON
         KICAD_SCRIPTING_WXPYTHON=ON
         USE_FP_LIB_TABLE=HARD_CODED_ON
         BUILD_GITHUB_PLUGIN=ON

[jean-pierre charras (jp-charras)]

Where is the bug?
If a label is common to 2 wires, it connects these 2 wires.

This is not a bug, but a user mistake.

[Kyle (2bluesc)]

Then there should be a junction requirement or ERC warning at the least. It's not obvious to the user.

[Javier Cardona (jcard0na)]

I second Kyle's opinion: it is counter intuitive to think that adding a label would silently connect two wires. If not reported by the ERC, this scenario should at least add a junction to make that connection evident.