Provide a value for flag() to be set when the value is provided

[zephraph]

2025.1.15 macos-arm64 (2025-01-26)

Okay, so I have a mise task that builds a rust crate. I want a windows option (to tell it to build for windows). When it has that option, I want to run cargo xwin build instead of cargo build. (Note I'm doing cross compilation so run_windows won't work for this case).

Here's the monstrosity I have right now

Note

This doesn't actually work, I was misreading the output.

[tasks."build:rust"]
run = """
{% set windows = flag(name='windows', default='') %}
{% if windows == 'true' %}
  {% set xwin = 'xwin ' %}
{% else %}
  {% set xwin = '' %}
{% endif %}
echo {{ xwin }}
cargo {{ xwin }}build --bin webview -F {{option(name='features', var=true, default='transparent devtools')}}
"""

There's a lot of problems to discuss:

1. I'm not using general sh logic as the docs recommend because the logs only show the first line of output. So if I added an echo 'hello' to the above script the logs would look like this

[build:rust] $ echo hello

I really just want to see the command output (the last line in this case). That's a bit of a separate issue, but still one to note.

2. It would seem like `{{ flag(name='windows', default='') | replace(from='true', to='xwin') }} should work if it's returning a string. Doesn't seem to be though.
3. cargo {% if flag(name='windows') %}xwin{% endif %} build seems like it should work, but that throws an exception b/c flag doesn't return a boolean
4. cargo {% if flag(name='windows') == 'true' %}xwin{% endif %} build doesn't work either

What I'd like to see

One solution that would be nice is just adding an arg to flag that would be the value if it's true. E.g.

{{ flag(name='windows', value='xwin') }}

Another would be to have flag just return a string. I've looked through the code and it looks like it's return some sort of template string that's more of a key? It's weird, because I can't usually get it to print out (it usually just prints as true or nothing).

e.g.

echo '{{ flag(name='windows') }}'

with --window passed will echo true

without it it will echo nothing (e.g. just run echo '')

Funnily, you can see the template string weirdness when you pass it through the reverse filter

echo '{{ flag(name='windows') | reverse }}'

will print GRA_KSAT_ESIM:swodniw:GRA_KSAT_ESIM. This special type doesn't play well with anything else. If we could at least have something we could do to normalize it into a string we'd have some more options.

Thoughts? Recommendations?

[jdx]

flag() doesn't really work the way you'd expect, it's just emitting a special key that gets gsub'ed later on. This has come up a couple of times and it might be fixable but it would require some refactoring and probably require us to parse the run script twice (once to get the args/flags, and another to generate the script). I was trying to avoid parsing twice but it's probably best to do so.

That said, I think you could solve your problem more easily with file tasks. I don't think this is documented but if you create a file task with extension .ps1 that would be preferred over others used with unix. The list of extensions is defined here: https://mise.jdx.dev/configuration/settings.html#windows_executable_extensions

EDIT: sorry I re-read this and see you're actually running this from unix

For now I think you'll just need to put this logic into bash, doing something like this:

local windows={{ flag(name='windows') }}
if [ "$windows" == true ]; then
# ...

that's the way I intended people would use this, but I definitely see why you're expecting templates to work here

[zephraph]

The .ps1 tip is pretty cool regardless

[zephraph]

Here's what I'm doing right now:

run = """
XWIN=$([ "{{ flag(name='windows') }}" = "true" ] && echo xwin || echo "")
cargo $XWIN build --bin webview -F {{option(name='features', var=true, default='transparent devtools')}}
"""

biggest problem is the log output

❯ mise run build:rust --windows
[build:rust] $ XWIN=$([ "true" = "true" ] && echo xwin || echo "")

because it's on two lines it's not showing what command it's actually running which is unfortunate (because I often check that to figure out why builds fail etc)

[jdx]

I think if you run with --verbose set you'll see the full output

[zephraph]

Ahh, I gotcha. I've been using very verbose a lot for debugging Tera issues, but I don't tend to use it much otherwise. Ironically I realized this probably wasn't even the right approach anyway.

run = "cargo {% if get_env(name='MISE_ENV', default='') == 'windows' %}xwin{% endif %} build --bin webview -F {{option(name='features', var=true, default='transparent devtools')}}"

All the issues are still valid though. I'd typically prefer to avoid using sh when writing tasks if I'm able. It's been an interesting exploration.

[roele]

What does seem to work is storing it in a variable first before the statement.

{% set windows = flag(name='windows') %}
{% if windows %}
  {% set xwin = 'xwin ' %}
{% else %}
  {% set xwin = '' %}
{% endif %}
echo {{ xwin }}

[jdx]

I'm surprised it does... I suspect it may not work well in all cases