Fix optimisation targets in build.zig (`-Drelease-fast` => `--release-fast` etc.)

[momumi]

Currently when using standardReleaseOptions() in build.zig, and running zig build --help shows (also in the docs):

Project-Specific Options:
 -Drelease-safe=[bool] optimizations on and safety on
 -Drelease-fast=[bool] optimizations on and safety off
 -Drelease-small=[bool] size optimizations on and safety off

However, zig build-exe --help uses:

 --release-fast build with optimizations on and safety off
 --release-safe build with optimizations on and safety on
 --release-small build with size optimizations on and safety off

If I try use zig build -Drelease-fast=true it actually produces a debug build, and zig build --release-fast doesn't work either.

[squeek502]

Are you calling setBuildMode on your target? Using the build.zig from zig init-exe with @compileLog(@import("builtin").mode); added to main.zig:

$ zig build
| std.builtin.Mode.Debug
$ zig build -Drelease-fast=true
| std.builtin.Mode.ReleaseFast

If I comment out the exe.setBuildMode(mode); line in build.zig, though, it reproduces your issue:

$ zig build -Drelease-fast=true
| std.builtin.Mode.Debug

[momumi]

It was my mistake, I was running the wrong executable (I was launching it manually with time ./test, when I should have used time ./zig-cache/bin/test.)

What confused me is zig build-exe uses a different cli options for release modes than zig build. I had built the executable with zig build-exe -Drelease-fast=true but that just produces a normal debug build because zig build-exe --release-fast is how you are supposed to call it (same for zig run). It'd be less confusing if they used the same flags.

[jecolon]

Hi all. I don't knwo if this is related, but check this out (tried on master and 0.7.1):

$ mkdir hello
$ cd hello
$ zig init-exe
$ zig build
$ ./zig-cache/bin/hello
info: All your codebase are belong to us.
$ zig build -Drelease-fast=true
$ ./zig-cache/bin/hello
[no output]
$ zig build -Drelease-small=true
$ ./zig-cache/bin/hello
[no output]
$ zig build -Drelease-safe=true
$ ./zig-cache/bin/hello
[no output]
$ zig build
$ ./zig-cache/bin/hello
info: All your codebase are belong to us.

So basically, any build with the -Drelease-* options produce an executable that produces no output. This is on linux amd64

[squeek502]

@jecolon That's due to the log level of release builds, since init-exe uses std.log.info. You can change it to use std.debug.print if you want to output to stderr for any build type.

Context for std.log being used in init-exe:

• #5943 (comment)
• #5941 (comment)

[jecolon]

@squeek502 ; Thanks for the info! That was exactly what was going on. Maybe as a usability tweak the auto-generated main.zig could use std.debug.print instead to avoid noob confusion. But nothing to lose sleep over. ;)