2 files changed, 68 insertions, 3 deletions

diff --git a/src/resolve.rs b/src/resolve.rs
index 14294d1..a01f5c5 100644
--- a/src/resolve.rs
+++ b/src/resolve.rs
@@ -64,6 +64,62 @@ enum ResolveState {
 	Resolved,
 }
 
+pub fn runtime_depends<'a, I>(
+	tasks: &'a TaskMap,
+	deps: I,
+) -> Result<HashSet<&'a OutputRef>, Vec<Error>>
+where
+	I: IntoIterator<Item = &'a OutputRef>,
+{
+	fn add_dep<'a>(
+		ret: &mut HashSet<&'a OutputRef>,
+		tasks: &'a TaskMap,
+		dep: &'a OutputRef,
+	) -> Vec<Error> {
+		if !ret.insert(dep) {
+			return Vec::new();
+		}
+
+		let task = &dep.task;
+		let task_def = match tasks.get(&task.id) {
+			Some(task) => task,
+			None => return vec![Error::TaskNotFound(DepChain(vec![task.clone()]))],
+		};
+
+		let output = match task_def.output.get(&dep.output) {
+			Some(output) => output,
+			None => {
+				return vec![Error::OutputNotFound(
+					DepChain(vec![task.clone()]),
+					dep.output.clone(),
+				)];
+			}
+		};
+
+		let mut errors = Vec::new();
+		for runtime_dep in &output.runtime_depends {
+			for mut error in add_dep(ret, tasks, runtime_dep) {
+				error.extend(task.clone());
+				errors.push(error);
+			}
+		}
+		errors
+	}
+
+	let mut ret = HashSet::new();
+	let mut errors = Vec::new();
+
+	for dep in deps {
+		errors.extend(add_dep(&mut ret, tasks, dep));
+	}
+
+	if !errors.is_empty() {
+		return Err(errors);
+	}
+
+	Ok(ret)
+}
+
 #[derive(Debug)]
 pub struct Resolver<'a> {
 	tasks: &'a TaskMap,
@@ -122,8 +178,15 @@ impl<'a> Resolver<'a> {
 			handle_errors(self.add_task(inherit, None));
 		}
 
-		for dep in task_def.get_depend_outputs() {
-			handle_errors(self.add_task(&dep.task, Some(&dep.output)));
+		match runtime_depends(self.tasks, task_def.get_depend_outputs()) {
+			Ok(rdeps) => {
+				for rdep in rdeps {
+					handle_errors(self.add_task(&rdep.task, Some(&rdep.output)));
+				}
+			}
+			Err(errors) => {
+				handle_errors(errors);
+			}
 		}
 
 		if ret.is_empty() {
diff --git a/src/types.rs b/src/types.rs
index af0fb92..0b85393 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -1,7 +1,7 @@
 use serde::{Deserialize, Serialize};
 use sha2::Sha256;
 use std::{
-	collections::{HashMap, HashSet},
+	collections::{BTreeSet, HashMap, HashSet},
 	fmt::Display,
 };
 
@@ -107,6 +107,8 @@ fn default_output_name() -> String {
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct Output {
 	pub path: Option<String>,
+	#[serde(default)]
+	pub runtime_depends: BTreeSet<OutputRef>,
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Eq, PartialOrd, Ord, Hash)]