Does not set DATABASE_URL when an env var containing "DATABASE_URL" is present

[turicas]

Description of problem

If a custom environment variable EXTERNAL_DATABASE_URL is set and no DATABASE_URL exists for the app, dokku-postgres will not create the DATABASE_URL when linking (will use another name). I think dokku-postgres checks for an environment variable containing DATABASE_URL in its name, instead of specifically checking for a variable named DATABASE_URL exactly.

Steps to Reproduce

Execute the following commands:

export APP_NAME=testapp
export DB_NAME=pg_testapp
dokku apps:create $APP_NAME

# First test (success) - if no env vars containing `DATABASE_URL` are present, the variable is created correctly
dokku postgres:create $DB_NAME -i postgres -I 16-bookworm --shm-size 2g
dokku postgres:link $DB_NAME $APP_NAME  # Creates DATABASE_URL

# Second test (fail)
dokku postgres:unlink $DB_NAME $APP_NAME
dokku config:set $APP_NAME EXTERNAL_DATABASE_URL=something
dokku postgres:link $DB_NAME $APP_NAME  # Creates DOKKU_POSTGRES_AQUA_URL

Actual Results

root@mymachine:~ 
# export APP_NAME=testapp
root@mymachine:~ 
# export DB_NAME=pg_testapp
root@mymachine:~ 
# dokku apps:create $APP_NAME
-----> Creating testapp...
-----> Creating new app virtual host file...
root@mymachine:~ 
# dokku postgres:create $DB_NAME -i postgres -I 16-bookworm --shm-size 2g
       Waiting for container to be ready
       Creating container database
       Securing connection to database
=====> Postgres container created: pg_testapp
=====> pg_testapp postgres service information
       Config dir:          /var/lib/dokku/services/postgres/pg_testapp/data
       Config options:                               
       Data dir:            /var/lib/dokku/services/postgres/pg_testapp/data
       Dsn:                 postgres://postgres:5605d910b8ec2e4cf1888febfbc7fa94@dokku-postgres-pg-testapp:5432/pg_testapp
       Exposed ports:       -                        
       Id:                  d4fd85937c9ba0207e8f021af8814775ea273782d903e48055d48d29f3cd39cf
       Internal ip:         172.17.0.26              
       Initial network:                              
       Links:               -                        
       Post create network:                          
       Post start network:                           
       Service root:        /var/lib/dokku/services/postgres/pg_testapp
       Status:              running                  
       Version:             postgres:16-bookworm     
root@mymachine:~ 
# dokku postgres:link $DB_NAME $APP_NAME
-----> Setting config vars
       DATABASE_URL:  postgres://postgres:5605d910b8ec2e4cf1888febfbc7fa94@dokku-postgres-pg-testapp:5432/pg_testapp
-----> Restarting app testapp
 !     App image (dokku/testapp:latest) not found
root@mymachine:~ 
# dokku postgres:unlink $DB_NAME $APP_NAME
-----> Unsetting DATABASE_URL
-----> Restarting app testapp
 !     App image (dokku/testapp:latest) not found
root@mymachine:~ 
# dokku config:set $APP_NAME EXTERNAL_DATABASE_URL=something
-----> Setting config vars
       EXTERNAL_DATABASE_URL:  something
-----> Restarting app testapp
 !     App image (dokku/testapp:latest) not found
root@mymachine:~ 
# dokku postgres:link $DB_NAME $APP_NAME
-----> Setting config vars
       DOKKU_POSTGRES_AQUA_URL:  postgres://postgres:5605d910b8ec2e4cf1888febfbc7fa94@dokku-postgres-pg-testapp:5432/pg_testapp
-----> Restarting app testapp
 !     App image (dokku/testapp:latest) not found

Expected Results

The very last postgres:link should set the env var named DATABASE_URL instead of DOKKU_POSTGRES_AQUA_URL.

Environment Information

dokku report APP_NAME output

Not applicable.

How (deb/make) and where (AWS, VirtualBox, physical, etc.) was Dokku installed?:

From dokku's Debian repository.

Additional information

dokku version 0.35.4