fix: running same task twice

[metaist]

While I was figuring out #21, I ended up adding in logic to prevent circularity. However, this also prevents the same task from running twice. But, ironically, having #21 done meant that it is easy to define a task with an argument and then have other tasks call it with different arguments.

[scripts]
build = "touch build/$1"
clean = "rm -rf build"
all = ["clean", "-mkdir build", "build foo", "build bar", "echo 'Done'"]

• Currently: runs clean, mkdir build, build foo, echo 'Done' (skips build bar)
• Expected: all of the steps run

[metaist]

Here's my analysis:

build => |touch
clean => |rm
all => clean => |mkdir => build => build => |echo

So is the problem when a composite task is called multiple times?

[metaist]

Only composite tasks can call other tasks. So the concern is that in the call chain you somehow end up calling yourself again.

Here's the simplest loop:

[scripts]
loop = ["loop"]
# loop => loop ...

If a composite task cannot be called twice, we prevent this loop.

[metaist]

Here's a more complicated loop:

[scripts]
a = ["b"]
b = ["a"]
# a=> b => a => b...

Ok, so far so good.

[metaist]

What about a more real-world use case:

[scripts]
clean = ["rm -rf build", "rm build-artifacts"]
build = "touch build/$1"
run = ["clean", "build foo", "mv foo new-location", "clean"]

In this case, clean is a composite task, but we're calling it twice at the same level-- it's not cycling back to run.