feat(task,executor): add CurrentAttempt resolution, wire maybeUnblockParent to resolve through it

1 files changed, 130 insertions, 0 deletions

diff --git a/internal/task/currentattempt_test.go b/internal/task/currentattempt_test.go
new file mode 100644
index 0000000..76661d8
--- /dev/null
+++ b/internal/task/currentattempt_test.go
@@ -0,0 +1,130 @@
+package task
+
+import (
+	"errors"
+	"testing"
+)
+
+type fakeLookup struct {
+	tasks map[string]*Task
+}
+
+func newFakeLookup() *fakeLookup {
+	return &fakeLookup{tasks: make(map[string]*Task)}
+}
+
+func (f *fakeLookup) GetTask(id string) (*Task, error) {
+	t, ok := f.tasks[id]
+	if !ok {
+		return nil, errors.New("not found")
+	}
+	return t, nil
+}
+
+func (f *fakeLookup) ListDependents(taskID string) ([]*Task, error) {
+	var out []*Task
+	for _, t := range f.tasks {
+		for _, d := range t.DependsOn {
+			if d == taskID {
+				out = append(out, t)
+				break
+			}
+		}
+	}
+	return out, nil
+}
+
+func TestCurrentAttempt_NoFixAttempt_ReturnsAnchorItself(t *testing.T) {
+	lookup := newFakeLookup()
+	lookup.tasks["a"] = &Task{ID: "a"}
+
+	got, err := CurrentAttempt(lookup, "a")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a" {
+		t.Errorf("got %q, want a", got.ID)
+	}
+}
+
+func TestCurrentAttempt_OneFixAttempt_ResolvesToIt(t *testing.T) {
+	lookup := newFakeLookup()
+	lookup.tasks["a"] = &Task{ID: "a", ParentTaskID: "parent-1"}
+	lookup.tasks["a-fix1"] = &Task{ID: "a-fix1", ParentTaskID: "parent-1", DependsOn: []string{"a"}}
+
+	got, err := CurrentAttempt(lookup, "a")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a-fix1" {
+		t.Errorf("got %q, want a-fix1", got.ID)
+	}
+}
+
+func TestCurrentAttempt_ChainOfFixAttempts_ResolvesToTip(t *testing.T) {
+	lookup := newFakeLookup()
+	lookup.tasks["a"] = &Task{ID: "a", ParentTaskID: "parent-1"}
+	lookup.tasks["a-fix1"] = &Task{ID: "a-fix1", ParentTaskID: "parent-1", DependsOn: []string{"a"}}
+	lookup.tasks["a-fix2"] = &Task{ID: "a-fix2", ParentTaskID: "parent-1", DependsOn: []string{"a-fix1"}}
+
+	got, err := CurrentAttempt(lookup, "a")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a-fix2" {
+		t.Errorf("got %q, want a-fix2 (tip of the chain)", got.ID)
+	}
+
+	// Resolving from an intermediate link in the chain also lands on the tip.
+	got, err = CurrentAttempt(lookup, "a-fix1")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a-fix2" {
+		t.Errorf("resolving from a-fix1: got %q, want a-fix2", got.ID)
+	}
+}
+
+// TestCurrentAttempt_DependentWithDifferentParent_NotTreatedAsFixAttempt
+// proves a task that depends on "a" but has a DIFFERENT ParentTaskID (e.g.
+// an unrelated Evaluator task depending on a Builder for scheduling reasons)
+// must not be mistaken for a's fix attempt.
+func TestCurrentAttempt_DependentWithDifferentParent_NotTreatedAsFixAttempt(t *testing.T) {
+	lookup := newFakeLookup()
+	lookup.tasks["a"] = &Task{ID: "a", ParentTaskID: "parent-1"}
+	lookup.tasks["unrelated"] = &Task{ID: "unrelated", ParentTaskID: "", DependsOn: []string{"a"}}
+
+	got, err := CurrentAttempt(lookup, "a")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a" {
+		t.Errorf("got %q, want a (unrelated dependent must not be treated as a fix attempt)", got.ID)
+	}
+}
+
+// TestCurrentAttempt_DependentWithMultipleDependsOn_NotTreatedAsFixAttempt
+// proves a fix attempt has exactly one DependsOn entry (the task it
+// supersedes); a task depending on "a" among several dependencies (e.g. an
+// Arbitration task depending on all 4 Evaluators) must not be mistaken for
+// a's fix attempt.
+func TestCurrentAttempt_DependentWithMultipleDependsOn_NotTreatedAsFixAttempt(t *testing.T) {
+	lookup := newFakeLookup()
+	lookup.tasks["a"] = &Task{ID: "a", ParentTaskID: "parent-1"}
+	lookup.tasks["multi-dep"] = &Task{ID: "multi-dep", ParentTaskID: "parent-1", DependsOn: []string{"a", "b"}}
+
+	got, err := CurrentAttempt(lookup, "a")
+	if err != nil {
+		t.Fatalf("CurrentAttempt: %v", err)
+	}
+	if got.ID != "a" {
+		t.Errorf("got %q, want a", got.ID)
+	}
+}
+
+func TestCurrentAttempt_UnknownAnchor_ReturnsError(t *testing.T) {
+	lookup := newFakeLookup()
+	if _, err := CurrentAttempt(lookup, "does-not-exist"); err == nil {
+		t.Error("expected an error for an unknown anchor ID")
+	}
+}