[Bug] Elastic Agent Panics when - null is set in an integration processor config

[BenB196]

For confirmed bugs, please report:

• Version: 8.17.1
• Operating System: Container
• Discuss Forum URL: https://discuss.elastic.co/t/elastic-agent-panic-with-nil-pointer-on-null-processor/373078
• Steps to Reproduce:
  1. Create an Elastic Agent policy
  2. Create an integration (integration must support defining processors)
  3. Deploy an Elastic Agent with the above policy & integration
  4. Confirm Elastic Agent works
  5. Update integration and add a process that is just the value of - null
  6. Observe that the Elastic Agent instantly panics and dies.

Processor config would look like:

processors:
  - null

Error observed:

{"log.level":"info","@timestamp":"2025-01-24T13:53:12.644Z","log.origin":{"function":"github.com/elastic/elastic-agent/internal/pkg/agent/application/monitoring/reload.(*ServerReloader).Start","file.name":"reload/reload.go","file.line":54},"message":"Starting monitoring server with cfg &config.MonitoringConfig{Enabled:true, MonitorLogs:true, MonitorMetrics:true, MetricsPeriod:\"\", FailureThreshold:(*uint)(nil), LogMetrics:true, HTTP:(*config.MonitoringHTTPConfig)(0xc000c9e480), Namespace:\"private.networking.development\", Pprof:(*config.PprofConfig)(nil), MonitorTraces:false, APM:config.APMConfig{Environment:\"\", APIKey:\"\", SecretToken:\"\", Hosts:[]string(nil), GlobalLabels:map[string]string(nil), TLS:config.APMTLS{SkipVerify:false, ServerCertificate:\"\", ServerCA:\"\"}, SamplingRate:(*float32)(nil)}, Diagnostics:config.Diagnostics{Uploader:config.Uploader{MaxRetries:10, InitDur:1000000000, MaxDur:600000000000}, Limit:config.Limit{Interval:60000000000, Burst:1}}}","log":{"source":"elastic-agent"},"ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2025-01-24T13:53:12.644Z","log.origin":{"function":"github.com/elastic/elastic-agent/internal/pkg/agent/application/monitoring.NewServer.exposeMetricsEndpoint.func1","file.name":"monitoring/server.go","file.line":96},"message":"creating monitoring API with cfg api.Config{Enabled:true, Host:\"http://localhost:6791\", Port:6791, User:\"\", SecurityDescriptor:\"\", Timeout:5000000000}","log":{"source":"elastic-agent"},"ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2025-01-24T13:53:12.644Z","log.logger":"api","log.origin":{"function":"github.com/elastic/elastic-agent-libs/api.(*Server).Start","file.name":"api/server.go","file.line":85},"message":"Starting stats endpoint","log":{"source":"elastic-agent"},"ecs.version":"1.6.0"}
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x5b0a888275ba]

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)