repro -P seems to check status of dependancies too often

[charlesbaynham]

DVC 0.91.0, Windows 10, pip

Description

Running dvc repro -P on a large graph seems to check all the early dependences once for each output, even if it has already been checked.

In the following repo:

                        step1.dvc
                          |
         ----------------------------------------
         |            |            |            |           
 step2_A.dvc  step2_B.dvc  step2_C.dvc  step2_D.dvc

Where each of the step 2 stages depends on steps 1, I think that calling dvc repro -P results in 4x checks of the outputs of step1.

I conclude this because, in my repo, I have several hundred stages in "step2" which all depend on a "step1" which is an import. When I run dvc repro -P, I get the

WARNING: DVC-file 'xxx.dvc' is locked. Its dependencies are not going to be reproduced.

message several hundred times.

[charlesbaynham]

In Discord, @efiop suggested problem might be in

dvc/dvc/repo/reproduce.py

Lines 78 to 90 in 11e56db

	if pipeline or all_pipelines:
	if all_pipelines:
	pipelines = active_pipelines
	else:
	stage = Dvcfile(self, target).load()
	pipelines = [get_pipeline(active_pipelines, stage)]
	targets = []
	for pipeline in pipelines:
	for stage in pipeline:
	if pipeline.in_degree(stage) == 0:
	targets.append(stage)
	else:

[efiop]

Fixed by #3645 . Kudos @charlesbaynham 🥇