Fix TcfCaV1 (Canada) OptimizedRange encoding to use Fibonacci, with backwards-compatible decoding#105
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chuff wants to merge 4 commits into
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Fix TcfCaV1 (Canada) OptimizedRange encoding to use Fibonacci, with backwards-compatible decoding#105chuff wants to merge 4 commits into
chuff wants to merge 4 commits into
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The Canada (TcfCaV1) VendorExpressConsent, VendorImpliedConsent, and DisclosedVendors fields are OptimizedRange per the spec, which is Fibonacci-coded in GPP. They were using EncodableOptimizedFixedRange (the legacy OptimizedIntRange used by TCF EU); switch them to the existing EncodableOptimizedFibonacciRange. Regenerate the affected test vectors (only populated-vendor cases change; empty/bitfield cases are encoder-agnostic) and add a round-trip test that exercises the Fibonacci range path with sparse vendor IDs. mvn test: 365 tests, 0 failures. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Per the GPP spec, PubRestrictions is N-ArrayOfRanges(6,2) where each record's ids are an OptimizedRange (Fibonacci coded). It was using EncodableArrayOfFixedIntegerRanges, which encodes ids as fixed-integer ranges (the legacy ArrayOfRanges form shared with TCF EU). Add EncodableArrayOfOptimizedFibonacciRanges, which reuses the existing EncodableOptimizedFibonacciRange / OptimizedFibonacciRangeEncoder for each record's ids, and point TcfCaV1's PUB_RESTRICTIONS field at it. The fixed variant is left untouched for TCF EU. Regenerate the affected TcfCaV1Test vectors and extend the round-trip test to cover PubRestrictions with sparse ids (Fibonacci range path). Note: verified by Java/ES cross-implementation agreement and round-trip, not yet against an external reference string. mvn test: 365 tests, 0 failures. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Strings produced by the pre-fix encoder used fixed-integer ranges for the OptimizedRange / N-ArrayOfRanges fields (VendorExpressConsent, VendorImpliedConsent, DisclosedVendors, PubRestrictions). Decoding those with the new Fibonacci datatypes would misread the data. The TcfCaV1 core and disclosed-vendors segments now decode by trying the spec-compliant (Fibonacci) interpretation first and, if it does not round-trip back to the input bitstring, falling back to the legacy (fixed-range) interpretation. Whichever re-encodes to the original bits is the one that produced the string. Decoded values are copied into the current (Fibonacci) fields, so the in-memory representation is identical regardless of which encoder produced the string. Tests: decode real pre-fix strings (vendors, PubRestrictions) and assert correct values. mvn test: 367 tests, 0 failures. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
…iant Adds a regression test using a real pre-fix (fixed-range) TcfCaV1 string: verifies it decodes correctly (CmpId, language, 14 express + 46 implied vendors) and that re-encoding emits the spec-compliant Fibonacci form. mvn test: 368 tests, 0 failures. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
Per the GPP Consent String Specification, the Canada (
TcfCaV1) section encodes several fields asOptimizedRange/N-ArrayOfRanges, both of which use Fibonacci coding. They were using fixed-integer encoders. This corrects the encoding and keeps existing strings decodable.Fixes:
VendorExpressConsent,VendorImpliedConsent,DisclosedVendors(OptimizedRange) —EncodableOptimizedFixedRange→EncodableOptimizedFibonacciRange.PubRestrictions(N-ArrayOfRanges(6,2), whoseidsare anOptimizedRange) — newEncodableArrayOfOptimizedFibonacciRangesthat reuses the existing FibonacciOptimizedRangefor each record's ids. The fixed variant is left untouched for TCF EU, which legitimately keeps the legacy encoding.(Base64 was already correct in this library — all
TcfCaV1segments use the compressed encoder. The traditional-vs-compressed issue only affected iabgpp-es.)Backwards compatibility
The
TcfCaV1core and disclosed-vendors segments decode by trying the spec-compliant (Fibonacci) interpretation first and, if it doesn't round-trip back to the input bitstring, falling back to the legacy (fixed-range) interpretation. Strings produced by the previous encoder still decode correctly. Empty / bitfield-form data encodes identically either way, so only populated range-form data changes on the wire.Note: this is backwards compatible on read (new code reads old strings). The encoder now emits Fibonacci strings, so consumers still running the previous code will not read the new range-form output — it is a deliberate wire-format correction for the affected fields.
Test plan
mvn test— full suite passes (368 tests)🤖 Generated with Claude Code