Vault database - datasource username and password not populated when multiple databases use same vault db role

Describe the bug

When using cloud.vault.databases to configure multiple datasources, it appears that username/password datasource properties don't get set if more than one entry refers to the same vault database role.

Our use case is an application that uses 2 separate databases in some environments, while in other environments rather than using 2 different databases, the application uses 2 different schemas co-located in the same database.

Spring cloud version: 2025.0.0

Sample

Highly abstracted, of course

Does not work:

  cloud:
    vault:
      databases:
        primary:
          enabled: true
          role: db1-dbuser
          backend: database/
          static-role: true
          username-property: spring.datasource.username
          password-property: spring.datasource.password
        other-database:
          enabled: true
          role: db1-dbuser
          backend: database/
          static-role: true
          username-property: spring.secondary-datasource.username
          password-property: spring.secondary-datasource.password

Works:

  cloud:
    vault:
      databases:
        primary:
          enabled: true
          role: db1-dbuser
          backend: database/
          static-role: true
          username-property: spring.datasource.username
          password-property: spring.datasource.password
        other-database:
          enabled: true
          role: db2-dbuser
          backend: database/
          static-role: true
          username-property: spring.secondary-datasource.username
          password-property: spring.secondary-datasource.password

Start by tracing the cloud.vault.databases configuration path and the code that populates datasource username and password properties for each database entry. Reproduce the supplied configuration with two entries sharing db1-dbuser, then compare it with distinct roles. Done means both entries receive their configured credentials when they share a Vault database role.