Clarify log record severity comparison

CHANGELOG.md

@@ -15,6 +15,9 @@ release.
 
 ### Logs
 
+- Clarify that `SeverityNumber` values are used when comparing severities.
+  ([#4552](https://github.com/open-telemetry/opentelemetry-specification/pull/4552))
+
 ### Baggage
 
 ### Profiles

specification/logs/data-model.md

@@ -286,8 +286,12 @@ this document. This field is optional.
 
 `SeverityNumber` is an integer number. Smaller numerical values correspond to
 less severe events (such as debug events), larger numerical values correspond to
-more severe events (such as errors and critical events). The following table
-defines the meaning of `SeverityNumber` value:
+more severe events (such as errors and critical events).
+
+For example `SeverityNumber=17` describes an error that is less
+critical than an error with `SeverityNumber=20`.
+
+The following table defines the meaning of `SeverityNumber` value:
 
 SeverityNumber range|Range name|Meaning
 --------------------|----------|-------
@@ -298,11 +302,6 @@ SeverityNumber range|Range name|Meaning
 17-20               |ERROR     |An error event. Something went wrong.
 21-24               |FATAL     |A fatal error such as application or system crash.
 
-Smaller numerical values in each range represent less important (less severe)
-events. Larger numerical values in each range represent more important (more
-severe) events. For example `SeverityNumber=17` describes an error that is less
-critical than an error with `SeverityNumber=20`.
-
 `SeverityNumber=0` MAY be used to represent an unspecified value.
 
 #### Mapping of `SeverityNumber`
@@ -420,9 +419,9 @@ capitalization or abbreviated, e.g. "Info" vs "Information").
 #### Comparing Severity
 
 In the contexts where severity participates in less-than / greater-than
-comparisons `SeverityNumber` field should be used. `SeverityNumber` can be
-compared to another `SeverityNumber` or to numbers in the 1..24 range (or to the
-corresponding short names).
+comparisons `SeverityNumber` field should be used.
+Special handling MAY be given to `SeverityNumber=0`
+when it is used to represent an unspecified severity.
 
 ### Field: `Body`
 

specification/logs/supplementary-guidelines.md

@@ -198,16 +198,15 @@ type SeverityProcessor struct {
 // if the record's severity is greater than or equal to p.Min.
 // Otherwise, the record is dropped (the wrapped processor is not invoked).
 func (p *SeverityProcessor) OnEmit(ctx context.Context, record *sdklog.Record) error {
-	if record.Severity() != log.SeverityUndefined && record.Severity() < p.Min {
+	if record.Severity() < p.Min {
 		return nil
 	}
 	return p.Processor.OnEmit(ctx, record)
 }
 
 // Enabled returns false if the severity is lower than p.Min.
 func (p *SeverityProcessor) Enabled(ctx context.Context, param sdklog.EnabledParameters) bool {
-	sev := param.Severity
-	if sev != log.SeverityUndefined && sev < p.Min {
+	if param.Severity < p.Min {
 		return false
 	}
 	if fp, ok := p.Processor.(sdklog.FilterProcessor); ok {