add deprecation log for --event_api.tags.illegal (#16507) (#16515)

- move `--event_api.tags.illegal` from option to deprecated_option
- add deprecation log when the flag is explicitly used
relates: #16356

Co-authored-by: Mashhur <[email protected]>
(cherry picked from commit a4eddb8)

Co-authored-by: kaisecheng <[email protected]>

logstash-core/lib/logstash/patches/clamp.rb

@@ -79,8 +79,16 @@ def define_deprecated_writer_for(option, opts, &block)
           new_flag = opts[:new_flag]
           new_value = opts.fetch(:new_value, value)
           passthrough = opts.fetch(:passthrough, false)
+          deprecated_msg = opts[:deprecated_msg]
 
-          LogStash::DeprecationMessage.instance << "DEPRECATION WARNING: The flag #{option.switches} has been deprecated, please use \"--#{new_flag}=#{new_value}\" instead."
+          LogStash::DeprecationMessage.instance <<
+            if new_flag
+             "DEPRECATION WARNING: The flag #{option.switches} has been deprecated, please use \"--#{new_flag}=#{new_value}\" instead."
+            elsif deprecated_msg
+              deprecated_msg
+            else
+              "DEPRECATION WARNING: The flag #{option.switches} has been deprecated and may be removed in a future release."
+            end
 
           if passthrough
             LogStash::SETTINGS.set(option.attribute_name, value)

logstash-core/lib/logstash/runner.rb

@@ -92,10 +92,6 @@ class LogStash::Runner < Clamp::StrictCommand
          :default => LogStash::SETTINGS.get_default("config.field_reference.escape_style"),
          :attribute_name => "config.field_reference.escape_style"
 
-  option ["--event_api.tags.illegal"], "STRING",
-         I18n.t("logstash.runner.flag.event_api.tags.illegal"),
-         :default => LogStash::SETTINGS.get_default("event_api.tags.illegal"),
-         :attribute_name => "event_api.tags.illegal"
 
   # Module settings
   option ["--modules"], "MODULES",
@@ -267,6 +263,12 @@ class LogStash::Runner < Clamp::StrictCommand
     I18n.t("logstash.runner.flag.http_port"),
     :new_flag => "api.http.port", :passthrough => true # use settings to disambiguate
 
+  deprecated_option ["--event_api.tags.illegal"], "STRING",
+         I18n.t("logstash.runner.flag.event_api.tags.illegal"),
+         :default => LogStash::SETTINGS.get_default("event_api.tags.illegal"),
+         :attribute_name => "event_api.tags.illegal", :passthrough => true,
+         :deprecated_msg => I18n.t("logstash.runner.tags-illegal-deprecated")
+
   # We configure the registry and load any plugin that can register hooks
   # with logstash, this needs to be done before any operation.
   SYSTEM_SETTINGS = LogStash::SETTINGS.clone

logstash-core/locales/en.yml

@@ -139,9 +139,11 @@ en:
       configtest-flag-information: |-
         You may be interested in the '--configtest' flag which you can use to validate
         logstash's configuration before you choose to restart a running system.
+      tags-illegal-deprecated: >-
+        The flag '--event_api.tags.illegal' is deprecated and will be removed in version 9.
       tags-illegal-warning: >-
         Setting `event_api.tags.illegal` to `warn` allows illegal values in the reserved `tags` field, which may crash pipeline unexpectedly.
-        This flag value is deprecated and may be removed in a future release.
+        This flag is deprecated and will be removed in version 9.
       # YAML named reference to the logstash.runner.configuration
       # so we can later alias it from logstash.agent.configuration
       configuration: &runner_configuration

logstash-core/spec/logstash/runner_spec.rb

@@ -380,6 +380,32 @@
       end
     end
 
+    context "event_api.tags.illegal" do
+      let(:runner_deprecation_logger_stub) { double("DeprecationLogger(Runner)").as_null_object }
+      let(:args) { ["--event_api.tags.illegal", "warn", "-e", pipeline_string] }
+      before(:each) { allow(runner).to receive(:deprecation_logger).and_return(runner_deprecation_logger_stub) }
+      DEPRECATED_MSG="The flag '--event_api.tags.illegal' is deprecated and will be removed in version 9"
+
+      it "gives deprecation message when setting to `warn`" do
+        expect(runner_deprecation_logger_stub).to receive(:deprecated)
+          .with(a_string_including "This flag is deprecated and will be removed in version 9")
+          .with(a_string_including DEPRECATED_MSG)
+        subject.run("bin/logstash", args)
+      end
+
+      it "gives deprecation message when setting to `rename`" do
+        expect(runner_deprecation_logger_stub).to receive(:deprecated)
+          .with(a_string_including DEPRECATED_MSG)
+        subject.run("bin/logstash", args)
+      end
+
+      it "does not give deprecation message when unset" do
+        expect(runner_deprecation_logger_stub).not_to receive(:deprecated)
+          .with(a_string_including DEPRECATED_MSG)
+        subject.run("bin/logstash", ["-e", pipeline_string])
+      end
+    end
+
     context "when :pipeline_workers is not defined by the user" do
       it "should not pass the value to the pipeline" do
         expect(LogStash::Agent).to receive(:new) do |settings|