feat(build): fuzz testing and git-cliff changelog automation

Add FuzzParseBytes and FuzzSanitizeYAMLEscapes in internal/model/fuzz_test.go.
Both targets run as regular seed-based tests in CI (go test ./...) and can be
run continuously via `task fuzz` (default 30 s per target; FUZZ_TIME=60s to
extend). Fuzz corpus failures are saved to testdata/fuzz/ for regression.

Add cliff.toml configuring git-cliff to generate Keep-a-Changelog-compatible
release notes from Conventional Commits. New tasks: `task changelog`
(regenerate full CHANGELOG.md) and `task changelog-next` (preview unreleased
entries without writing). Requires git-cliff (brew/cargo install git-cliff).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 This project uses [Semantic Versioning](https://semver.org).
 
+## [0.2.27] - 2026-06-25
+
+### Added
+
+- **Fuzz testing** — `FuzzParseBytes` and `FuzzSanitizeYAMLEscapes` in `internal/model/fuzz_test.go` verify that neither the YAML parser nor the escape sanitizer panics on arbitrary input. Successful parses are also checked for structural integrity (non-nil pipeline, no empty job names). Run with `task fuzz` (default 30 s per target; set `FUZZ_TIME=60s` to extend). Found failures are saved to `testdata/fuzz/` for regression.
+
+- **Changelog automation** — `cliff.toml` configures [git-cliff](https://git-cliff.org) to generate Keep-a-Changelog–compatible release notes from Conventional Commits. `task changelog` regenerates `CHANGELOG.md` from the full git history; `task changelog-next` previews only unreleased commits without writing. Install git-cliff with `brew install git-cliff` or `cargo install git-cliff`.
+
 ## [0.2.26] - 2026-06-25
 
 ### Changed

README.md

@@ -6,7 +6,7 @@
 
 <p align="center">
   <a href="LICENSE"><img src="https://img.shields.io/badge/license-Apache%202.0-blue.svg" alt="License"></a>
-  <a href="CHANGELOG.md"><img src="https://img.shields.io/badge/release-v0.2.26-blue.svg" alt="Release"></a>
+  <a href="CHANGELOG.md"><img src="https://img.shields.io/badge/release-v0.2.27-blue.svg" alt="Release"></a>
 </p>
 
 > **Disclaimer:** This tool was built through iterative AI-assisted development with [Claude](https://claude.ai). It is experimental, incomplete, and not intended for production use. Coverage of GitLab CI keywords is best-effort and may lag behind GitLab's evolving spec. Use it at your own discretion — no correctness guarantees are made. Contributions and bug reports are welcome.
@@ -69,11 +69,18 @@ task test         # run Go unit tests
 task lint-go      # run go vet
 task validate     # run the binary against all testdata fixtures
 task ci           # full check: vet → test → build → validate
+task fuzz         # run fuzz tests for the YAML parser (Ctrl-C to stop; FUZZ_TIME=60s to set duration)
+task changelog    # regenerate CHANGELOG.md from git history via git-cliff
+task changelog-next  # preview unreleased section (dry-run, no file written)
 task build-windows  # cross-compile for Windows x64 (requires a tagged commit → glint-<tag>.exe)
 task build-linux    # cross-compile for Linux x64 (requires a tagged commit → glint-<tag>-linux-amd64)
 task clean        # remove build artifacts
 ```
 
+**Optional tools:**
+
+- [git-cliff](https://git-cliff.org) — changelog generator used by `task changelog`. Install with `brew install git-cliff` or `cargo install git-cliff`.
+
 ## Project structure
 
 ```

ROADMAP.md

@@ -119,5 +119,5 @@ The SVG renderer and terminal tree cover the basic layout. These would bring it
 - ~~**`glint explain <rule-id>`**~~ — ✓ shipped v0.2.20; prints rule description, rationale, bad-YAML example, and fix; `glint explain` (no arg) lists all rules
 - ~~**Semantic versioning and first release**~~ — shipped as `v0.1.0` (2026-06-07)
 - ~~**Subcommand CLI**~~ — shipped as `v0.2.0` (2026-06-11); `glint check` / `glint graph [mode]` with ruff-style `--help`
-- **Changelog automation** — generate release notes from Conventional Commits via `git-cliff` or similar
-- **Fuzz testing** — add a `go test -fuzz` target for the YAML parser to harden it against malformed input
+- ~~**Changelog automation**~~ — ✓ shipped v0.2.27; `cliff.toml` configures git-cliff to produce Keep-a-Changelog–compatible release notes from Conventional Commits; `task changelog` regenerates `CHANGELOG.md`, `task changelog-next` previews unreleased entries
+- ~~**Fuzz testing**~~ — ✓ shipped v0.2.27; `FuzzParseBytes` and `FuzzSanitizeYAMLEscapes` in `internal/model/fuzz_test.go`; seeds run as regular tests in CI; `task fuzz` runs them continuously (default 30 s)

Taskfile.yml

@@ -175,6 +175,20 @@ tasks:
     generates:
       - "{{.BINARY}}-{{.TAG}}-linux-amd64"
 
+  fuzz:
+    desc: "Run fuzz tests for the YAML parser and sanitizer (set FUZZ_TIME=60s to control duration, default 30s)"
+    cmds:
+      - "{{.GO}} test -fuzz=FuzzParseBytes          -fuzztime=${FUZZ_TIME:-30s} ./internal/model/"
+      - "{{.GO}} test -fuzz=FuzzSanitizeYAMLEscapes -fuzztime=${FUZZ_TIME:-30s} ./internal/model/"
+
+  changelog:
+    desc: "Regenerate CHANGELOG.md from git history (requires git-cliff — see README)"
+    cmd: git cliff --config cliff.toml --output CHANGELOG.md
+
+  changelog-next:
+    desc: "Preview unreleased changelog entries without writing (requires git-cliff)"
+    cmd: git cliff --config cliff.toml --unreleased
+
   clean:
     desc: Remove build artifacts
     cmd: rm -f {{.BINARY}} {{.BINARY}}-*.exe {{.BINARY}}-*-linux-amd64

cliff.toml

@@ -0,0 +1,65 @@
+# git-cliff configuration for glint
+# Install: brew install git-cliff  OR  cargo install git-cliff
+# Usage:   task changelog            -- regenerate full CHANGELOG.md
+#          task changelog-next       -- preview unreleased section (dry-run)
+
+[changelog]
+header = """
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
+This project uses [Semantic Versioning](https://semver.org).
+"""
+body = """
+{% if version %}\
+## [{{ version | trim_start_matches(pat="v") }}] - {{ timestamp | date(format="%Y-%m-%d") }}
+
+{% else %}\
+## [Unreleased]
+
+{% endif %}\
+{% for group, commits in commits | group_by(attribute="group") %}\
+### {{ group | upper_first }}
+
+{% for commit in commits %}\
+- {% if commit.scope %}**{{ commit.scope }}**: {% endif %}\
+{{ commit.message | upper_first }}\
+{% if commit.breaking %} **[BREAKING]**{% endif %}
+
+{% endfor %}\
+{% endfor %}\
+"""
+trim = true
+footer = ""
+postprocessors = []
+
+[git]
+conventional_commits = true
+filter_unconventional = true
+split_commits = false
+commit_preprocessors = [
+  # Drop Co-Authored-By trailers (should not appear in subjects, but guard anyway).
+  { pattern = "Co-Authored-By:.*", replace = "" },
+]
+commit_parsers = [
+  # Breaking changes (type! or scope!) — promote above everything else.
+  { message = "^[a-z]+\\([a-z-]+\\)!:|^[a-z]+!:", group = "Breaking Changes" },
+  { message = "^feat",     group = "Added" },
+  { message = "^fix",      group = "Fixed" },
+  { message = "^perf",     group = "Changed" },
+  { message = "^refactor", group = "Changed" },
+  # Maintenance commits — omit from the changelog body.
+  { message = "^docs",   skip = true },
+  { message = "^style",  skip = true },
+  { message = "^test",   skip = true },
+  { message = "^chore",  skip = true },
+  { message = "^build",  skip = true },
+  { message = "^claude", skip = true },
+]
+protect_breaking_commits = false
+filter_commits = true
+tag_pattern = "v[0-9].*"
+topo_order = false
+sort_commits = "oldest"

internal/model/fuzz_test.go

@@ -0,0 +1,77 @@
+package model
+
+import "testing"
+
+// FuzzParseBytes ensures the YAML parser never panics on arbitrary input and
+// that successful parses return a structurally sound Pipeline.
+// Run with: go test -fuzz=FuzzParseBytes ./internal/model/
+// Found failures are saved to testdata/fuzz/FuzzParseBytes/.
+func FuzzParseBytes(f *testing.F) {
+	// Seed corpus: representative inputs covering the main code paths in
+	// ParseBytes, including the sanitizeYAMLEscapes pre-processing step.
+	seeds := [][]byte{
+		{},
+		[]byte("null"),
+		[]byte("stages: [build]\nbuild-job:\n  stage: build\n  script: echo ok\n"),
+		[]byte(".base:\n  script: [make]\nchild:\n  extends: .base\n  stage: test\n"),
+		[]byte("stages: [a, b]\njob-a:\n  stage: a\n  script: run\njob-b:\n  stage: b\n  needs: [job-a]\n  script: run\n"),
+		[]byte("*undefined_anchor"),
+		[]byte("- item1\n- item2\n"),
+		[]byte("my-job: \"just a string\"\n"),
+		[]byte("my-job:\n  stage: [build, test]\n"),
+		[]byte("# glint: ignore GL007\nlegacy:\n  only: [main]\n  script: ok\n"),
+		[]byte("workflow:\n  rules:\n    - if: '$CI_COMMIT_BRANCH == \"main\"'\n      when: always\njob:\n  script: echo ok\n"),
+		[]byte("include:\n  - local: other.yml\njob:\n  script: echo ok\n"),
+		[]byte("job:\n  script: echo ok\n  when: on_failure\n  rules:\n    - if: '$VAR =~ /^us\\//'\n"),
+		[]byte("job:\n  stage: test\n  image:\n    name: golang:1.21\n    entrypoint: ['']\n  parallel:\n    matrix:\n      - PLATFORM: [linux, darwin]\n  script: go build\n"),
+		[]byte("default:\n  retry: 2\n  timeout: 1h30m\nvariables:\n  ENV: production\nstages: [build, test, deploy]\n"),
+		[]byte("&anchor\n  script: [echo ok]\njob:\n  <<: *anchor\n  stage: build\n"),
+	}
+	for _, s := range seeds {
+		f.Add(s)
+	}
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		p, err := ParseBytes(data)
+		if err != nil {
+			return // errors are acceptable; panics are not
+		}
+		if p == nil {
+			t.Fatal("ParseBytes returned nil pipeline with nil error")
+		}
+		for name := range p.Jobs {
+			if name == "" {
+				t.Fatal("ParseBytes produced a job with an empty name")
+			}
+		}
+	})
+}
+
+// FuzzSanitizeYAMLEscapes ensures the escape sanitizer never panics and never
+// produces output shorter than its input (it can only expand \/ to \\/).
+func FuzzSanitizeYAMLEscapes(f *testing.F) {
+	seeds := [][]byte{
+		{},
+		[]byte("stage: build"),
+		[]byte(`if: "$CI_BRANCH =~ /^us\//"`),
+		[]byte(`"pattern: /^us\//"`),
+		[]byte(`'single quoted \/ unchanged'`),
+		[]byte(`"\n\t\r"`),
+		[]byte(`"nested \"quote\" inside"`),
+		[]byte(`'it''s fine'`),
+		[]byte(`"unclosed`),
+		{'"', '\\'},      // double-quoted string ending with a lone backslash
+		{'"', '\\', '/'}, // the exact sequence being rewritten
+	}
+	for _, s := range seeds {
+		f.Add(s)
+	}
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		out := sanitizeYAMLEscapes(data)
+		if len(out) < len(data) {
+			t.Fatalf("sanitizeYAMLEscapes shrank output: input len=%d output len=%d\ninput: %q",
+				len(data), len(out), data)
+		}
+	})
+}