diff --git a/src/build/build_step.go b/src/build/build_step.go
index 1c274c2ab..d028eb67d 100644
--- a/src/build/build_step.go
+++ b/src/build/build_step.go
@@ -343,6 +343,16 @@ func buildTarget(state *core.BuildState, target *core.BuildTarget, runRemotely b
 			return err
 		}
 
+		// Wait for any new dependencies added by post-build commands before continuing.
+		for _, dep := range target.Dependencies() {
+			dep.WaitForBuild()
+			if dep.State() >= core.DependencyFailed { // Either the target failed or its dependencies failed
+				// Give up and set the original target as dependency failed
+				target.SetState(core.DependencyFailed)
+				return fmt.Errorf("error in post-rule dependency for %s: %s", target.Label, dep.Label)
+			}
+		}
+
 		if runRemotely && len(outs) != len(target.Outputs()) {
 			// postBuildFunction has changed the target - must rebuild it
 			log.Info("Rebuilding %s after post-build function", target)
diff --git a/src/core/build_target.go b/src/core/build_target.go
index 166dbb515..fb91a935b 100644
--- a/src/core/build_target.go
+++ b/src/core/build_target.go
@@ -1653,6 +1653,16 @@ func (target *BuildTarget) AddMaybeExportedDependency(dep BuildLabel, exported,
 	}
 }
 
+// RegisterDependencyTarget registers a build target to be used for a dependency label on the given target.
+func (target *BuildTarget) RegisterDependencyTarget(dep BuildLabel, deptarget *BuildTarget) {
+	info := target.dependencyInfo(dep)
+	if info == nil {
+		log.Fatalf("Target %s doesn't contain dependency %s.\n", target.Label, dep)
+	} else {
+		info.deps = append(info.deps, deptarget)
+	}
+}
+
 // IsTool returns true if the given build label is a tool used by this target.
 func (target *BuildTarget) IsTool(tool BuildLabel) bool {
 	for _, t := range target.Tools {
diff --git a/src/parse/asp/builtins.go b/src/parse/asp/builtins.go
index e3a04b53a..cc82f74b6 100644
--- a/src/parse/asp/builtins.go
+++ b/src/parse/asp/builtins.go
@@ -1125,6 +1125,7 @@ func addDep(s *scope, args []pyObject) pyObject {
 	dep := s.parseLabelInPackage(string(args[1].(pyString)), s.pkg)
 	exported := args[2].IsTruthy()
 	target.AddMaybeExportedDependency(dep, exported, false, false)
+	target.RegisterDependencyTarget(dep, s.state.Graph.Target(dep))
 	// Queue this dependency if it'll be needed.
 	if target.State() > core.Inactive {
 		err := s.state.QueueTarget(dep, target.Label, false, core.ParseModeNormal)