Is there a way to merge two rez environments?

[neo-mashiro]

Hello! I have a resolved rez environment with 3 packages. This is the runtime environment where I launch my application.

rez-env pkg_a pkg_b pkg_c

Meanwhile, I also have a build script for pkg_c which is a C++ package with Python bindings. Running the build-env script gives me the right environment to directly invoke the build system. This is the build environment where I develop, build and debug pkg_c.

rez-build -s  # generate the build-env script

My question is, is there a way to merge the runtime environment and build environment into one single rez context? What I'm looking for is a single environment where I can both build pkg_c and launch my application.

I'm asking this because it's not always convenient to have 2 separate environments. For example,

• from the build environment, it's often impossible to attach gdb to my host application process which is in the runtime environment.
• from the runtime environment, it's not always possible to launch a C++ IDE or debugging tools because the runtime environment does not have all the build dependencies.

I noticed that rez-env has a -b option to create a build environment, but I'm not sure what it does. Does it create a build environment where I can build every single package in the requested list? What if there are 100 packages requested? Can I also launch my application from this environment? (as if it's a runtime environment?)