'NoneType' object is not subscriptable

[DavidGOrtega]

Bug Report

I came up with this issue by other paths, but I tried to find an easy way to isolate it.

steps to reproduce

dvc remote add s3 s3://
dvc remote default s3
dvc run --no-exec -n train \
  --outs-persist model.data \
   ./train.sh

git add dvc.yaml
dvc commit

outputs

ERROR: unexpected error - 'NoneType' object is not subscriptable 
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Please provide information about your setup

Output of dvc version:

WARNING: Unable to detect supported link types, as cache directory '.dvc/cache' doesn't exist. It is usually auto-created by commands such as `dvc add/fetch/pull/run/import`, but you could create it manually to enable this check.
DVC version: 1.1.11
Python version: 3.7.6
Platform: Darwin-19.0.0-x86_64-i386-64bit
Binary: False
Package: pip
Supported remotes: azure, gdrive, gs, hdfs, http, https, s3, ssh, oss
Repo: dvc, git
Filesystem type (workspace): ('apfs', '/dev/disk1s5')

[efiop]

Ran into this as well. Working on a fix...