🚸 Improvement: Grab the value for the default source directory from the sfdx project file instead

[e02d96ec16]

Enhancement request

Currently, the commands that employ an argument for pointing to the source folder (usually -d) are set to have a default value (force-app/main/default) in order to allow them to be optional (ie better usability).

I would like for the force-app part of this default value to be dynamically resolved instead, to the default package directory defined in the SFDX project file.

Example:

• currently: force-app/main/default
• desirable: sfdx-source/my_ns_prefix/main/default

Here's a SFDX project file (excert from sfdx-falcon) for reference:

{
  "packageDirectories": [
    { "path": "sfdx-source/my_ns_prefix", "default": true },
    { "path": "sfdx-source/unpackaged"},
    { "path": "sfdx-source/untracked"}
  ],
  "namespace": "my_ns_prefix",
  "sfdcLoginUrl": "https://login.salesforce.com",
  "sourceApiVersion": "43.0"
}

I would classify this as "Nice to have".