CI/CD AWS_ variable validation regression

Summary

We have been setting variables at the group level to use as values for AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY on the project level.

!29959 (closed) broke this functionality.

Steps to reproduce

Group CI/CD Variables

Type	Key	Value	Protected	Masked
Var	PROD_ACCESS_KEY_ID	...	❌	✅
Var	PROD_SECRET_ACCESS_KEY	...	❌	✅

Project CI/CD Variables

Type	Key	Value	Protected	Masked	Environments
Var	AWS_ACCESS_KEY_ID	$PROD_ACCESS_KEY_ID	✅	❌	production
Var	AWS_SECRET_ACCESS_KEY	$PROD_SECRET_ACCESS_KEY	✅	❌	production

What is the current bug behavior?

The following error message is shown, and the Add/Update Variable button is disabled.

This variable does not match the expected pattern.

What is the expected correct behavior?

Group-level variables should be allowed values for AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY at the project level.

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Debian 9.2
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.6.5p114
Gem Version:	2.7.10
Bundler Version:1.17.3
Rake Version:	12.3.3
Redis Version:	5.0.7
Git Version:	2.26.2
Sidekiq Version:5.2.7
Go Version:	unknown

GitLab information
Version:	12.10.1-ee
Revision:	695c29abcf7
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	PostgreSQL
DB Version:	10.9
URL:		https://gitlab.
HTTP Clone URL:	https://gitlab./some-group/some-project.git
SSH Clone URL:	git@gitlab.:some-group/some-project.git
Elasticsearch:	yes
Geo:		no
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers: saml

GitLab Shell
Version:	12.2.0
Repository storage paths:
- default: 	/opt/gitlab/git-data/repositories
GitLab Shell path:		/opt/gitlab/embedded/service/gitlab-shell
Git:		/opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 12.2.0 ? ... OK (12.2.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 2
Try fixing it:
sudo service gitlab stop
sudo pkill -u git -f sidekiq
sleep 10 && sudo pkill -9 -u git -f sidekiq
sudo service gitlab start
Please fix the error above and rerun the checks.
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Reply by email is disabled in config/gitlab.yml
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab App ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...

Redis version >= 4.0.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.5)
Git version >= 2.22.0 ? ... yes (2.26.2)
Git user has default SSH configuration? ... yes
Active users: ... 742
Is authorized keys file accessible? ... yes
Elasticsearch version 5.6 - 6.x? ... yes (7.4.2)
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished

Possible fixes

Revert or amend !29959 (closed).