When resolving dependencies using manifest, do not fail if an optional plugin cannot be retrieved

[PierreBtz]

Version report

Jenkins and plugins versions report:

(FWIW version doesn't matter)

Jenkins: 2.249.3.1
OS: Mac OS X - 10.16
---
trilead-api:1.0.8
jdk-tool:1.4
command-launcher:1.4
script-security:1.75
echarts-api:4.9.0-1
structs:1.20
apache-httpcomponents-client-4-api:4.5.10-2.0
operations-center-server:2.249.0.8
support-core:2.70
cloudbees-analytics:1.27
mailer:1.32.1
bootstrap4-api:4.5.2-1
jquery3-api:3.5.1-1
command-launcher:1.4
workflow-api:2.40
jackson2-api:2.11.2
credentials:2.3.13
operations-center-agent:2.249.0.1
cloudbees-assurance:2.138.0.21
operations-center-context:2.249.0.3
bouncycastle-api:2.18
operations-center-license:2.249.0.1
variant:1.3
async-http-client:1.7.24.3
cloudbees-license:9.47
cloudbees-administrative-monitors:1.0.1
cloudbees-ha:4.25
jaxb:2.3.0.1
cloudbees-uc-data-api:4.43
font-awesome-api:5.14.0-1
token-macro:2.12
script-security:1.75
nectar-license:8.28
snakeyaml-api:1.27.0
node-iterator-api:1.5.0
workflow-step-api:2.22
metrics:4.0.2.6
plugin-util-api:1.2.5
popper-api:1.16.0-6
trilead-api:1.0.8
jdk-tool:1.4
cloudbees-folder:6.14
cloudbees-folders-plus:3.10
junit:1.37
mock-security-realm:1.4
scm-api:2.6.4
display-url-api:2.3.3
cloudbees-monitoring:2.10
cloudbees-support:3.25
mapdb-api:1.0.9.0
google-login:1.6

• What Operating System are you using (both controller, and any agents involved in the problem)?

masOS Big Sur

Reproduction steps

You will need an Update Center referencing a plugin that declares an optional plugin that is not in said Update Center.

1. For reproduction purposes, let's use this CloudBees Update Center: https://jenkins-updates.cloudbees.com/update-center/envelope-core-oc/update-center.json?version=2.249.3.1/update-center.json

2. Try to run the tool on a plugin that declares an optional dependency that is not in this Update Center, eg in our case operations-center-context:2.249.0.3 (make sure to specify the version so that the resolution is done from the MANIFEST of the hpi).

Results

Expected result:

Success

Actual result:

Failure because the optional plugin cannot be downloaded:

Plugin operations-center-context:2.249.0.3 unable to find dependant plugin cloudbees-template in update center https://jenkins-updates.cloudbees.com/update-center/envelope-core-oc/update-center.json?version=2.249.3.1/update-center.json
	at io.jenkins.tools.pluginmanager.impl.PluginManager.start(PluginManager.java:200)
	at io.jenkins.tools.pluginmanager.impl.PluginManager.start(PluginManager.java:149)
	at io.jenkins.tools.pluginmanager.cli.Main.main(Main.java:70)
	Suppressed: io.jenkins.tools.pluginmanager.impl.PluginNotFoundException: Plugin operations-center-sso:2.249.0.2 (via operations-center-context:2.249.0.3) unable to find dependant plugin cloudbees-template in update center https://jenkins-updates.cloudbees.com/update-center/envelope-core-oc/update-center.json?version=2.249.3.1/update-center.json
		at io.jenkins.tools.pluginmanager.impl.PluginManager.getLatestPluginVersion(PluginManager.java:848)
		at io.jenkins.tools.pluginmanager.impl.PluginManager.resolveDependenciesFromManifest(PluginManager.java:910)
		at io.jenkins.tools.pluginmanager.impl.PluginManager.resolveDirectDependencies(PluginManager.java:1013)
		at io.jenkins.tools.pluginmanager.impl.PluginManager.resolveRecursiveDependencies(PluginManager.java:1047)
		at io.jenkins.tools.pluginmanager.impl.PluginManager.findPluginsAndDependencies(PluginManager.java:627)
		at io.jenkins.tools.pluginmanager.impl.PluginManager.start(PluginManager.java:192)
		... 2 more