[richardmoe]

Problem

On push events in tagless repositories (like ps-terraform-config), semrel lint fell through to ListCommitsSinceTag(nil) which walked the entire commit history. In ps-terraform-config this meant linting all 2927 commits and finding 1705 violations in historical commits that predate conventional commit adoption.

The recent fix in #17 (2992c59) fixed the pull_request path to use GITHUB_BASE_REF→HEAD, but the push path was unchanged. Any consumer repo that:

• triggers the reusable commitlint workflow on push events, AND
• has no release tags

would fail every push-event lint check.

Failing run: https://github.com/nrkno/ps-terraform-config/actions/runs/31571178223/job/94033318956?pr=1976

Root cause

msg="lint range" event=push from="" to=HEAD commit_count=2927
...
error="1705 commit violation(s) found"

On push, fromRef resolved to empty (no tags), so lint fell through to the bootstrap path (ListCommitsSinceTag(nil)), linting the entire repository history.

Fix

Read the pushed commits directly from the GitHub event payload (GITHUB_EVENT_PATH) on push events. This validates exactly the commits included in the push, not the entire repository history.

Fallback preserved: when the event payload is unavailable or unreadable, semrel falls back to the previous tag-based range. Explicit --from-ref always overrides automatic detection.

Changes

File	Change
internal/env/env.go	PushCommit type + loadPushPayload() — parses push event JSON
internal/cli/cli.go	Push lint routes through event payload; commitsFromPushPayload() helper
internal/env/env_test.go	2 tests: payload parsing + missing-file graceful degradation
internal/cli/cli_test.go	3 tests: payload used, violations fail, --from-ref overrides
integration_test.go	E2E: payload wins over bad repo history
docs/api-reference.md	Updated range table + explanatory note
docs/configuration.md	Updated --from-ref and GITHUB_EVENT_NAME descriptions
docs/log.md	Dated entry
CHANGELOG.md	New fix entry

Verification

go test -race -count=1 ./...                    # all OK
go test -race -count=1 -tags integration ./...   # all OK
go vet ./...                                     # clean
go build ./cmd/semrel                            # clean