Libraries not installed from registry cannot be detected as already installed dependencies of other libraries

When a library is either installed from anywhere other than the main package registry, the owner field for the spec is always empty because owner isn't a supported field that is read from either the library.json or a library.properties field. But owner is a supported field for a library dependency in a library.json file. So if a library has detailed dependency list including library owners and a user installs both that library and it's dependencies from any source other than the registry, the dependency finder will re-install all of the dependencies because they are cannot be matched because of the missing owner field.

Detailed Example:

Manually install low-level library

• User installs SensorModbusMaster directly from GitHub using the command pio pkg install --library https://github.com/EnviroDIY/SensorModbusMaster/
• The SensorModbusMaster library is installed in the lib_deps folder as expected.
• The SensorModbusMaster library.json does not support an owner field; the package manager has no way of knowing the package owner.

Manually install library depending on low-level library

• User installs YosemitechModbus directly from GitHub using the command pio pkg install --library https://github.com/EnviroDIY/YosemitechModbus
• The YosemitechModbus library is installed in the lib_deps folder as expected.
• The package manager scans the library.json manifest of the YosemitechModbus library and sees the dependency named SensorModbusMaster with the owner envirodiy.
• The package manager attempts to match the dependency with already installed libraries. It cannot be matched to the already installed SensorModbusMaster because the owner of the installed library is unknown.
  • The failing test is in the test_pkg_spec function at line 297
• The package manager installs a second version of the SensorModbusMaster library from the PlatformIO registry.

Result

• The user now has two possibly different versions of the same library installed which is unlikely to be what was desired.

Possible Solutions

• support and read an owner field for the library.json file
  • requires modification of the spec and validation of library.json files in addition to the machinery that reads the spec
  • requires library authors to add the owner field
  • requires validation on submission to the registry that the owner field in the manifest is aligned with the user submitting the library
• remove check for matching owners when checking if a library is already installed.
  • only requires removing a few lines of code
  • users may end up with mis-matched libraries and other packages that do not work together in cases where the same package has been submitted by multiple owners or forked libraries are used
• Where possible, infer the library owner from the installation location if a library is installed from outside of the registry
  • This is probably only possible for istallations from sources like GitHub where the repo owner could be used
  • This would only help in cases where the repo owner exactly matches the registry owner.

Start in platformio/package/manager/base.py, especially test_pkg_spec around lines 276-306 and the failing comparison near line 297. Reproduce the SensorModbusMaster and YosemitechModbus installation sequence, then trace how owners are obtained for non-registry libraries and matched against dependency owners. Done means an already installed external dependency is not duplicated while owner mismatches remain safe.