[KARAF-1600] Avoid duplicate feature and bundle resolution when installing cascading features

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.8
• Fix Version/s: 2.2.9, 2.3.0, 3.0.0
• Labels: features
• Assignee: Gert Vanthienen
• Reporter: Raúl Kripalani
• Created: 29/Jun/12 17:07
• Updated: 17/Dec/12 10:44
• Resolved: 10/Aug/12 03:17

Description

Currently, if one has multiple features depending on each other, where the same features or bundles are referenced twice or more, Karaf will attempt to resolve/install them as many times as they are traversed.

E.g., pseudo-code:

feature a, contains:
  feature camel-core
  feature camel-spring
  bundle 1
  bundle 2

feature b, contains:
  feature camel-jetty
  feature camel-http
  bundle 3
  bundle 4

feature all, contains:
  feature a
  feature b

When one installs feature "all", Karaf will end up resolving/attempting to install camel-core multiple times as it hits it via transitive dependencies (via a, via camel-jetty, via camel-http, etc.).

As a result, an unnecessary delay is experienced and this could be optimised to perform a two-phase feature installation procedure instead:

• calculate the install plan (kind of like building an effective POM in Maven) and prune duplicates
• perform the install plan