ERC "Label not connected to anything" in basic bus usage
ERC reports a 'Label not connected to anything' error in a specific scenario where a single usage of the associated bus net label exists on a sheet, even if there is a hierarchical pin setup for the bus. This scenario assumes that the pin is connected to another sheet on the top sheet, and that the other sheet uses the net label.
The expected behavior is that there would be no error or warning generated by ERC because the signal (net) is, in fact, used elsewhere in the schematic.
I searched for similar ERC bugs. There are some that relate to having two net names on a single signal, but I did not find any that match the type of error I am encountering. Further, there were questions about whether some of these other bugs might not technically be correct behavior. In this case, however, I do not believe there is any ambiguity. Please see the reproduce steps, which demonstrate both a 'good' and 'bad' use case for near identical nets.
Please note: I am very new to KiCAD and I do not presume to know all the ins/outs of the application. However, I did try to search out this problem both on the internet and in the gitlab bug DB. Further, the behavior just felt very misleading and wrong. However, please feel free to correct me if this is expected behavior. Regards.
Steps to reproduce
- Create a schematic with two sheets.
- On the first sheet, create a simple schematic such as shown below. Note that A0 and A3 exist in only one place on this sheet, while A1 exists in two places.
- On the second sheet, create a simple circuit that uses all three of the bus net labels:
- On the top sheet, connect the hierarchical pins:
- Run the ERC validation:
- Note that A0 and A2 are flagged as errors on the first sheet. A1, the signal that is used a second time, has no warnings or errors
- Note that A0, A1, and A2 are all flagged as error on the second sheet.
- Run the netlist export
- Note that the nets are correct. A0 and A2 have two connection points, and A1 has three connection points
Application: KiCad Schematic Editor Version: (6.0.9-0), release build Libraries: wxWidgets 3.1.5 libcurl/7.79.1 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.11 nghttp2/1.45.1 Platform: macOS Version 12.4 (Build 21F79), 64 bit, Little endian, wxMac Build Info: Date: Oct 29 2022 19:31:49 wxWidgets: 3.1.5 (wchar_t,wx containers) Boost: 1.80.0 OCC: 7.6.3 Curl: 7.64.1 ngspice: 37 Compiler: Clang 12.0.0 with C++ ABI 1002 Build settings: KICAD_USE_OCC=ON KICAD_SPICE=ON