We have been caching the paths to the plugins but before we would only
cache the specific plugin that we were looking for. This meant that we
might search through all of the plugin directories before finding the
specific module we were interested in. The next plugin we needed we
might again search through all the plugin directories before finding the
plugin we wanted.
This new code will cache all the potential plugins in each directory
searched. For a play that only uses one plugin we'll only search
through directories until we encounter the directory that has the proper
plugin. For a large playbook with many plugins used we'll search
through each directory at most once each.
From v1: 68e86de26f730c2ba403
77731440f3