tagparser

Fork of github.com/vmihailenco/tagparser, maintained by Quad4 under the module path github.com/Quad4-Software/tagparser/v2. The upstream helper is small and stable. This fork updates the Go toolchain, module path, layout, CI, and tests.

The parser reads comma-separated tag names and key:value options, including quoted segments and parentheses inside values.

Install

go get github.com/Quad4-Software/tagparser/v2@latest

For local development against a checkout, point a replace directive at it:

replace github.com/Quad4-Software/tagparser/v2 => ../tagparser

import "github.com/Quad4-Software/tagparser/v2/pkg/tagparser"

Layout

Path	Contents
pkg/tagparser	Public API: Parse, Tag, HasOption
internal/parser	Incremental parser over bytes
internal	StringToBytes and BytesToString, unsafe on non-App Engine builds
scripts/ci	Local CI parity scripts: test-all.sh, scan-all.sh, setup-go.sh

Testing

• Unit tests are table-driven cases in tagparser_test.go, invariant_test.go, and tagparser_more_test.go. The low-level scanner has its own tests in internal/parser/parser_test.go.
• Property tests using pbt live in pbt_test.go and cover no-panic guarantees, determinism, and HasOption against a plain map.
• Fuzz targets are FuzzParse and FuzzDeterminism on the parser, plus FuzzUntrustedTag for hostile inputs (NULs, long runs, bidi and unicode). The internal package has FuzzBytesToString, FuzzStringToBytes, and FuzzConvertRoundtrip asserting the unsafe conversions match plain string and byte copy semantics.
• internal/unsafe_invariants_test.go checks len and cap on StringToBytes for non-App Engine builds. Run the safe build with go test -tags=appengine ./internal/....
• stress_test.go covers concurrent parses, long inputs, many comma-separated segments, and deep parentheses. These are skipped under -short.
• Benchmarks run with go test ./... -bench=. -benchmem -run=^$ and include BenchmarkParse subcases, parallel and throughput benches, and the internal/parser BenchmarkParser_ReadSep.

Example fuzz runs:

go test ./pkg/tagparser -fuzz=FuzzParse -fuzztime=30s
go test ./internal -fuzz=FuzzConvertRoundtrip -fuzztime=30s

License

BSD 2-clause. See LICENSE. Original copyright remains with the vmihailenco authors. Fork maintenance is attributed here.