Variables not Expanded in Included Fragment

[olivia-banks]

Imagine a situation like the below:

.
├── foo.c
├── build
    └── build.ninja     # parent
└── support
    └── fragment.ninja  # child

Where the user invokes n2 in the build directory, which then:

# build/build.ninja

# Sets some variables
proj_root = ..

# Includes the fragment (child)
include ../support/fragment.ninja

Inside the fragment file, we might do something like:

# support/fragment.ninja

build foo.o: cc ${proj_root}/foo.c

However, if we do something like this, we get an error like:

n2: error: ../support/fragment.ninja: input /foo.c missing

This is not a failure that happens on ninja or samu.

---

olivia@exbop build % for impl in ninja samu n2; do
        rm -f foo.o
        echo $impl; $impl
done
ninja
ninja: warning: build log version is too old; starting over
[1/1] cc -c -o foo.o ../foo.c
samu
[1/1] cc -c -o foo.o ../foo.c
n2
n2: error: ../support/fragment.ninja:6: input /foo.c missing

[evmar]

I confirmed this. Thanks for the thorough report!

It seems like this code is the issue:

n2/src/load.rs

Lines 185 to 192 in 5295c19

	fn evaluate_and_read_file(
	&mut self,
	file: EvalString<&str>,
	envs: &[&dyn eval::Env],
	) -> anyhow::Result<()> {
	let evaluated = self.evaluate_path(file, envs);
	self.read_file(evaluated)
	}

when evaluating a statement like include $foo/bar, we correctly do use envs to ensure that $foo is evaluated using the current in-scope variables (in the evaluate_path call), but we also need to change the API to pass envs through the subsequent .read_file() to use as context for variables found within that file.

I'm unlikely to work on this soon, but if you wanted to try to fix it I'd review it.

[olivia-banks]

I'll submit a patch when I get around to it. Thanks for the quick response!

@teowelton any interest?

[evmar]

I added a (current expecting failure) test for this issue, so be sure to take a look at the change linked above if you want to fix it. It gave me an excuse to fix an unrelated CI issue and clean up some versioning churn.