@@ -152,17 +152,37 @@ public class NetworkInstrumentation {
152152 }
153153 }
154154
155- let serverTimingPattern = #"traceparent;desc=['\"]00-([0-9a-f]{32})-([0-9a-f]{16})-01['\"]"#
156-
157155 func addLinkToSpan( span: Span , valStr: String ) {
158- let regex = try ! NSRegularExpression ( pattern: serverTimingPattern)
156+
157+ let serverTimingPattern = #"traceparent;desc=['"]00-([0-9a-f]{32})-([0-9a-f]{16})-01['"]"#
158+
159+ guard let regex = try ? NSRegularExpression ( pattern: serverTimingPattern) else {
160+ self . logger. log ( level: . fault) {
161+ " Regex failed to compile "
162+ }
163+ // Intentional hard failure in both Debug and Release builds
164+ preconditionFailure ( " Regex failed to compile. Likely programmer error in edit of serverTimingPattern regex: # \( serverTimingPattern) # " )
165+ }
166+
167+ // Match the regex against the input string
159168 let result = regex. matches ( in: valStr, range: NSRange ( location: 0 , length: valStr. utf16. count) )
160- // per standard regex logic, number of matched segments is 3 (whole match plus two () captures)
161- if result. count != 1 || result [ 0 ] . numberOfRanges != 3 {
169+
170+ // Ensure there's exactly one match and the correct number of capture groups
171+ guard result. count == 1 , result [ 0 ] . numberOfRanges == 3 ,
172+ let traceIdRange = Range ( result [ 0 ] . range ( at: 1 ) , in: valStr) ,
173+ let spanIdRange = Range ( result [ 0 ] . range ( at: 2 ) , in: valStr) else {
174+ // If the match or capture groups are invalid, log and return early
175+ // Also, prevent over-long log output
176+ let truncatedValStr = valStr. count > 255 ? String ( valStr. prefix ( 252 ) ) + " ... " : valStr
177+ self . logger. log ( level: . debug) {
178+ " Failed to match traceparent string: \( truncatedValStr) "
179+ }
162180 return
163181 }
164- let traceId = String ( valStr [ Range ( result [ 0 ] . range ( at: 1 ) , in: valStr) !] )
165- let spanId = String ( valStr [ Range ( result [ 0 ] . range ( at: 2 ) , in: valStr) !] )
182+
183+ let traceId = String ( valStr [ traceIdRange] )
184+ let spanId = String ( valStr [ spanIdRange] )
185+
166186 span. setAttribute ( key: " link.traceId " , value: traceId)
167187 span. setAttribute ( key: " link.spanId " , value: spanId)
168188 }
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