Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

[0.0.11] - 2026-11-01

🚀 Features

font: read any font of a collection and hand back the decoded sfnt

🐛 Bug Fixes

font: add FontError::IndexOutOfRange last so the other variants keep their value

📝 Documentation

string: list how parse_pattern differs from parsePatternOrRegExp
stop linking to items only built with random-entropy

✅ Tests

font: kill the surviving mutants of the sfnt rebuild

📦 Build

deps: Bump the actions group across 1 directory with 2 updates

👷 CI/CD

release: pin helpers4/action-release by commit SHA
release: release with helpers4/action-release

0.0.10 - 2026-10-30

🚀 Features

bytes: add media_type_of and media_type_of_path
color: add blend, premultiply, Hsb and unit channels
font: add CSS font matching and font file reading
geometry: add SVG path helpers and Matrix::rect_to_rect
kiwi: add a Kiwi schema and message decoder
string: add match_glob_ignore_case and parse_pattern

♻️ Refactoring

geometry: write the path scanners without index loops

📝 Documentation

agents: document the MSRV policy and the no_std status
agents: document the free-functions naming policy

✅ Tests

font: avoid words the spell checker flags
security: fuzz ByteReader
kill the surviving mutants of the new modules

📦 Build

deps: Bump unicode-normalization

0.0.9 - 2026-10-24

🚀 Features

animation: add the animation module
array: add toggle, toggle_by and replace_or_append
color: add Rgba, and CSS output for Rgb and Hsl
geometry: add Size, matrix constructors, Rect operations, fit and simplify_polyline
id: add the id module
random: add the random module and the random-entropy feature
string: add compare_natural and GlobSet

📝 Documentation

bytes: mention the ByteReader in the README module table

✅ Tests

security: fuzz the new parsers

👷 CI/CD

CI-CD: document the equivalent and hanging mutants of the new modules
CI-CD: make Release stop early when a tagged version has unreleased changes
CI-CD: run the full mutation run in 12 shards
security: run cargo-deny on all features
security: run the fuzzers through ClusterFuzzLite
security: add zizmor, dependency review, OSV-Scanner and a daily audit
security: fix the zizmor findings in the workflows

0.0.8 - 2026-10-24

🚀 Features

bytes: add ByteReader, zigzag_encode and zigzag_decode
geometry: add Matrix, Point and Rect
string: add match_glob

🔧 Miscellaneous

add the geometry commit scope

📦 Build

deps: Bump the actions group with 5 updates
deps: Bump the actions group with 4 updates

0.0.7 - 2026-10-11

🚀 Features

cache: add a bounded LRU cache
env: add typed getters — bool, int, list, duration
hex: add base64 and base32 encoding and decoding
release: compute api-since.json and gate PRs on cargo-semver-checks
string: add words, excerpt, escape_regex, levenshtein_distance/similarity, remove_diacritics

🐛 Bug Fixes

release: give cargo-cyclonedx’s override filename its own .cdx suffix

📝 Documentation

agents: add the replace-with-helpers4 skill for Rust
agents: add the add-helper skill and native-alternatives.json for std
scorecard: add the OpenSSF Best Practices badge
security: list the supported releases as 0.0.x
expand CONTRIBUTING.md to the level of the TypeScript one

✅ Tests

add cargo-fuzz targets for the six untrusted-input parsers
add benchmarks for the string, array and number additions
use assert_eq! for the emptiness checks clippy 1.99 now rejects

📦 Build

deps: Bump the actions group with 3 updates

👷 CI/CD

coherency: add a coherency script for module wiring and rustdoc
deps: group major updates and attach a CycloneDX SBOM to releases
release: run mutation testing and coverage on the exact tagged release
release: attach the Sigstore bundle to the release next to the crate
add one aggregating status check for the branch ruleset

0.0.6 - 2026-09-23

🚀 Features

ansi: add the ansi module: strip, contains, visible_len, Style, Color
bytes: add the bytes module: read_u16/32/64, find, xor, constant_time_eq, format_size, parse_size
ci: add the ci module: Provider, detect, is_ci, is_pull_request, Status, overall, render_report
color: add the color module: Rgb, Hsl, ParseColorError, mix, contrast_ratio, best_text_color
commit: add the commit module: Commit, Bump, ParseCommitError, bump_for, is_valid, emoji_for
date: add the date module: Date, Weekday, DateError, is_leap_year, days_in_month
fs: add the fs module: write_atomic, read_to_string_opt, walk, normalize, is_within
function: add the function module: compose, pipe, Memoize, retry, backoff, TokenBucket
future: add the future module: block_on, now_or_never, yield_now, join, join_all
license: add the license module: lookup, normalize, Expression, Category, LicenseInfo, header
markdown: add the markdown module: escape, link, inline_code, code_block, blockquote, table, heading_slug
secret: add the secret module: Secret, redact, mask, detect, scan, TokenKind
set: add the set module: union_all, intersection_all, toggle, to_sorted_vec, jaccard, subsets
url: add the url module: Url, percent_encode/decode, parse_query, build_query, join_path
version: add the version module: Version, VersionReq, ParseVersionError, compare, satisfies

🔧 Miscellaneous

coherency: exclude two mutants no test can catch
coherency: tell typos about the test data that looks like typos

♻️ Refactoring

bytes: replace hand-rolled index loops so mutants cannot hang

📝 Documentation

agents: list the new modules in llms.txt
list the new modules in the README

✅ Tests

bytes: cover multi-digit fractions and drop the redundant unit guards
commit: cover type characters, ordinary footers and 400-year cycles
secret: fix a property that did not hold

👷 CI/CD

skip the PR mutation run when the diff is too big for the job
cap the weekly feature powerset at depth 3
stop the feature powerset check from growing unbounded on every PR

0.0.5 - 2026-09-22

🚀 Features

iter: add the iter module: chunk, min_max and first_duplicate
validate: add the validate module: is_valid_email, is_uuid and is_slug

🐛 Bug Fixes

validate: gate the whole spec file, not just the proptest block
validate: don’t require string to compile validate alone

📝 Documentation

agents: list the iter and validate modules in llms.txt
add the Scorecard badge and the iter/validate modules to the README
add # Arguments and # Returns to every helper’s rustdoc

✅ Tests

iter: exclude two equivalent mutants in min_max

0.0.4 - 2026-09-21

🚀 Features

duration: add the duration module: parse, format and ParseDurationError
map: add the map module: pick, omit and map_values

📝 Documentation

agents: list the duration and map modules in llms.txt

✅ Tests

map: bind the expected value so the test compiles on Rust 1.85

0.0.3 - 2026-09-21

🚀 Features

array: add key_by, duplicates and interleave
number: add the number module: lerp, round_to, mean, median, percentage, gcd, lcm
string: add title_case, constant_case, squish, indent and unescape_html

📝 Documentation

agents: list the new helpers in llms.txt
add the Codecov badge to the README
rewrite the README and point the homepage to helpers4.dev/rust
add the pre-1.0 notice to the README and fix its install section

✅ Tests

number: exclude the mutants that only hang
number: cover lcm(0, 0)

👷 CI/CD

add the OpenSSF Scorecard workflow
notify the website when a release is published

0.0.2 - 2026-09-20

🚀 Features

cache: add ExpiringMap
http: add bearer_token
net: add is_valid_hostname and HostnameError
net: add is_public_ip
time: add unix_now_millis
time: add unix_now and ClockError

🐛 Bug Fixes

net: reject hostnames whose last label is a number

🔧 Miscellaneous

ignore the VS Code local history

♻️ Refactoring

hex: name the hex parameter hex instead of s
net: make the CIDR prefix precondition explicit

📝 Documentation

net: spell out what is_public_ip guarantees and what it cannot know
document the ExpiringMap capacity bound and the unix_now_millis saturation

✅ Tests

cache: check that a non-empty map is not empty
benchmark is_public_ip and ExpiringMap

👷 CI/CD

exclude the equivalent ExpiringMap sweep-guard mutant
publish with trusted publishing only

[0.0.1] - 2026-09-19

🚀 Features

array: add cartesian_product
array: add group_by
array: add count_by
array: add equals_unordered
array: add intersects
array: add symmetric_difference
array: add intersection
array: add difference
array: add unique_by
array: add unique
env: add remove
env: add set and InvalidKeyError
env: add get
env: add parse
hex: add decode_array
hex: add decode_to_slice
hex: add decode and DecodeError
hex: add encode_upper
hex: add encode
string: add escape_html
string: add dedent
string: add truncate
string: add slugify
string: add kebab_case
string: add snake_case
string: add pascal_case
string: add camel_case
scaffold crate with string::capitalize

🔧 Miscellaneous

drop the redundant helpers4 scope

♻️ Refactoring

string: colocate tests, property tests and benches with each helper
adopt a strict lint table

📝 Documentation

agents: describe the CI checks and the reusable workflows
agents: note that coverage counts each generic instantiation
release: accept an org-level token and make the environment optional
string: drop the Since marker in favor of a computed api-since.json
string: list the string helpers in llms.txt

✅ Tests

array: benchmark unique, difference, group_by and equals_unordered
hex: benchmark encode and decode
string: benchmark the case, slug, escape and dedent helpers

📦 Build

anchor the published file patterns to the crate root
publish only sources, benchmarks and entry-point docs

👷 CI/CD

simplify the release inputs
drop the website notification from the release workflow
add the crates.io release workflow
confirm suspected benchmark regressions before reporting them
say so when a diff generates no mutant
raise the benchmark noise threshold to avoid false regressions
add benchmark and mutation-testing jobs
configure cargo-mutants
run the minimal-versions job on nightly despite rust-toolchain.toml
split CI into reusable jobs with PR and main validation