resolve: more idiomatic error formatting

1 files changed, 26 insertions, 24 deletions

diff --git a/src/resolve.rs b/src/resolve.rs
index 95b798a..f3ad284 100644
--- a/src/resolve.rs
+++ b/src/resolve.rs
@@ -4,23 +4,12 @@ use std::fmt;
 use crate::types::*;
 
 #[derive(Debug)]
-pub enum Error {
-	TaskNotFound(Vec<TaskRef>),
-	DependencyCycle(Vec<TaskRef>),
-}
+pub struct DepChain(pub Vec<TaskRef>);
 
-impl Error {
-	fn extend(&mut self, task: TaskRef) {
-		let tasks = match self {
-			Error::TaskNotFound(ref mut tasks) => tasks,
-			Error::DependencyCycle(ref mut tasks) => tasks,
-		};
-		tasks.push(task);
-	}
-
-	fn write_tasks(f: &mut fmt::Formatter, tasks: &Vec<TaskRef>) -> fmt::Result {
+impl fmt::Display for DepChain {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		let mut first = true;
-		for task in tasks.iter().rev() {
+		for task in self.0.iter().rev() {
 			if !first {
 				write!(f, " -> ")?;
 			}
@@ -33,19 +22,32 @@ impl Error {
 	}
 }
 
+#[derive(Debug)]
+pub enum Error {
+	TaskNotFound(DepChain),
+	DependencyCycle(DepChain),
+}
+
+impl Error {
+	fn extend(&mut self, task: TaskRef) {
+		let tasks = match self {
+			Error::TaskNotFound(ref mut tasks) => tasks,
+			Error::DependencyCycle(ref mut tasks) => tasks,
+		};
+		tasks.0.push(task);
+	}
+}
+
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		let tasks = match self {
+		match self {
 			Error::TaskNotFound(tasks) => {
-				write!(f, "Task not found: ")?;
-				tasks
+				write!(f, "Task not found: {}", tasks)
 			}
 			Error::DependencyCycle(tasks) => {
-				write!(f, "Dependency Cycle: ")?;
-				tasks
+				write!(f, "Dependency Cycle: {}", tasks)
 			}
-		};
-		Error::write_tasks(f, tasks)
+		}
 	}
 }
 
@@ -80,14 +82,14 @@ impl<'a> Resolver<'a> {
 	pub fn add_task(&mut self, task: &TaskRef) -> Vec<Error> {
 		match self.resolve_state.get(task) {
 			Some(ResolveState::Resolving) => {
-				return vec![Error::DependencyCycle(vec![task.clone()])]
+				return vec![Error::DependencyCycle(DepChain(vec![task.clone()]))]
 			}
 			Some(ResolveState::Resolved) => return vec![],
 			None => (),
 		}
 
 		let task_def = match self.tasks.get(task) {
-			None => return vec![Error::TaskNotFound(vec![task.clone()])],
+			None => return vec![Error::TaskNotFound(DepChain(vec![task.clone()]))],
 			Some(task_def) => task_def,
 		};