zig info command - print lib path, std path and global cache path

[Sergeeeek]

Implements the enhancement #4427

Creating this PR before everything is finished to get early feedback.

A couple of questions:

1. stage0 uses Blake2 to compute the compiler id hash, can I use that for self hosted or does it need to be re-implemented? Will be implemented in Partially implement cache hash API in zig #4635
2. How to pass a version string from build.zig? Are there any examples/docs? I haven't found anything. Will use addBuildOption

Progress

Self hosted:

• Add an info command to zig
• lib path
• std path
• global cache path (different for self hosted and stage1)
• zig info --json
• zig info --help

Example output:

$ zig info
lib_dir         	/home/sergeeeek/Work/zig/build/lib/zig
std_dir         	/home/sergeeeek/Work/zig/build/lib/zig/std
global_cache_dir	/home/sergeeeek/.cache/zig/(stage1|self_hosted)

$ zig info --json
{
  "lib_dir": "/home/sergeeeek/Work/zig/build/lib/zig",
  "std_dir": "/home/sergeeeek/Work/zig/build/lib/zig/std",
  "global_cache_dir": "/home/sergeeeek/.cache/zig/(stage1|self_hosted)"
}

$ zig info --help
Usage: zig info [options]

   Outputs path to zig lib dir, std dir and the global cache dir.

Options:
   --help                 Print this help and exit
   --json                 Output as json instead of a table format

Stage 1:

• Add an info command to zig
• Call the self-hosted info command, so the output is the same

[Sergeeeek]

How to pass a version string from build.zig? Are there any examples/docs? I haven't found anything.

I'm thinking creating a separate file called version.txt at the root of the project and reading it from cmake and at comptime in self hosted.

I guess I'd also need to call git to get the revision inside a comptime, not sure if that's a good solution though.

Any help on choosing the best approach would be appreciated.

[Sergeeeek]

Found the zig blake2 implementation, working on translating cache_hash.cpp into zig, which is used by current get_compiler_id

[andrewrk]

Found the zig blake2 implementation, working on translating cache_hash.cpp into zig, which is used by current get_compiler_id

I'll work on merging #4635 soon, I think you might be duplicating efforts here

[ifreund]

I'd argue that json output is overkill for this. A simple table would be easier to work with from shell scripts without depending on something like jq.

[data-man]

A simple table would be easier to work

Or to add additional argument:
zig info [--json]

[Sergeeeek]

Found the zig blake2 implementation, working on translating cache_hash.cpp into zig, which is used by current get_compiler_id

I'll work on merging #4635 soon, I think you might be duplicating efforts here

Oh didn't notice that PR, I'll stop then. Didn't get that far anyway :)

A simple table would be easier to work

Or to add additional argument:
zig info [--json]

Agreed, that's a good idea

[Sergeeeek]

Figuring out how to pass version from build.zig takes too long for me 😅

I'd like to split self hosted version resolution into a separate PR and merge this in its current state.

[daurnimator]

Maybe also have a --text option to set it back to non-json?

Perhaps it should be a --format=json argument instead?

[Sergeeeek]

It's text by default, why add an additional --text argument?

[daurnimator]

It's common in many command line tools so that aliases and defaults set in wrappers can be undone.

[Sergeeeek]

Added a --format option, also changed error messages to better match other zig commands.

[Sergeeeek]

Found an inconsistency between Linux and OSX that affects this PR: fs.selfExePath() on Linux resolves symlinks and on OSX it doesn't.

The fix to that is very simple, I can just call os.readlinkZ on OSX like it currently does on linux. Can I include that in this PR?

[Sergeeeek]

Actually, looks like symlinks in selfExePath are only resolved on Linux. Not sure what to do about it, but I would propose to resolve them on all platforms.

For example brew usually installs binaries into it's own location and then links them to /usr/local/bin, in which case zig info would stop working.

[Sergeeeek]

Another solution is to remove link resolution in selfExePath on linux and do it inside zig info, but I'm not sure how much stuff is dependent on that behavior

[andrewrk]

Thanks @Sergeeeek. I made some adjustments and then it landed in e26dda5.