dependencies: remove capstone

[jsiverskog]

the implementation already supports that capstone may not be installed. capstone is somewhat slow to install on some platforms (e.g. raspberry pi), and not always needed.

[ithinuel]

Hello, Thank you for the contribution.

As I understand this, this is a matter of weighing the benefit for people using this step command and relying on it printing the asm versus people installing pyocd from pip on "slow" systems.

I don't personally have an opinion on that matter and don't feel legitimate to make the call on this.

[carlosperate]

Not indicating if this should be removed or kept in install_requires, but just to add a small comment that:
if it is going to be removed from install_requires it might be better if it goes into a different extras_require.
Maybe a new one, like pemicro? and maybe at that point it'd be good as well to add a third called all to include all options.
On top of that it would also be good to update all the documentation indicating how to install the different dependencies.

Of course, it's understandable not wanting to do the extra work without first knowing if a PR is going to be accepted, I just wanted to point this out to have it in consideration as well.

[ithinuel]

@carlosperate Thank you! I am not familiar enough with this aspect of python to do this myself but I’m happy to review/approve/merge such PR (provided there’s some explanations for me to understand what I’m approving).

[carlosperate]

Yeah, I'm happy to help!

The main idea is to create a new group for capstone, we can call it something like dissassembler, and add that info to the docs/installing.md and docs/installing_on_non_x86.md pages.
Additionally, for convinience, we can add an all group to include [pemicro, tests and dissassembler].

Ah, and we should update this error message as well:

pyOCD/pyocd/commands/commands.py

Lines 1732 to 1734 in 90ee63a

	if not IS_CAPSTONE_AVAILABLE:
	raise exceptions.CommandError("Disassembly is not available because the Capstone library is not installed. "
	"To install Capstone, run 'pip install capstone'.")

The way it would then work is that by default pip install pyocd won't include these extra dependencies, and pip install pyocd[all] would do (or pip install pyocd[dissasembler] would only includes the dissasembler, etc).

As the capstone version is still locked to 4.x this is useful for platforms like Raspberry Pi and macOS arm64, as there aren't wheels for those platforms before v5.0.2, so they might end up building it from source during the installation:

• https://pypi.org/project/capstone/4.0.2/#files

pyOCD/setup.cfg

Line 53 in 90ee63a

capstone>=4.0,<5.0

Alternatively we could increase the max capstone version, that might require some testing as well, but I've never looked into this specific feature, so not sure how much there might be to test. What would you prefer @ithinuel?

@jsiverskog once we know the next steps would you like to update this PR yourself? I'd like to make sure your contribution is recognised and credited, but I also understand it's been a year and maybe you've moved onto other things.

[cederom]

I am FreeBSD user and Capstone always caused troubles here as system package is different from required by pyOCD, when used in virtual environment, had to built from sources, had to patch the upstream, etc etc :D

Also on rPI building this package every time in a new environment adds to already time consuming bootstrap.

I know this is really useful feature but not always required. Having this as runtime not build time option would be of a great benefit :-)