Description of the problem / feature request:

When overriding the copts and linkopts build configuration with None values in a transition, Bazel crashes with a NullPointerException.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

def _my_transition_impl(settings, attr):
    return {
        "//command_line_

One of the consumers of our system uses curly braces for content replacement in strings.

Due to the way that SD currently uses curly braces in the build process there is no way I can have a string that includes the braces for consumption.

I have tried a number of ways to escape the braces with no luck

Other languages and templating systems seem to use the concept of using double curly b

We're moving in the direction of Pants no longer registering all of its plugins by default and instead requiring users to opt-in. For example, you must explicitly opt in to pants.backend.python.lint.isort in V2, whereas V1 has pants.backend.python activated by default.

However, there is no good way to discover the possible backends outside of looking at the source code for this project.

Bloop supports globs for source files since #1176.

The same should be done for resources.

Is your feature request related to a problem? Please describe.
Running any bazel build command on a fresh system with no Python, within a workspace that uses rules_haskell, will eventually yield an error of the form:

Repository rule _config_python3_toolchain defined at:
  /root/.cache/bazel/_bazel_root/abad448bf464eefeaf2734c3cc8cdd46/external/rules_haskell/haskell/ghc_bindist.bzl:59