feat: verify copyright year

.pre-commit-config.yaml

@@ -1,5 +1,5 @@
 # yamllint disable-line rule:line-length
-# SPDX-FileCopyrightText: 2023 - 2024 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+# SPDX-FileCopyrightText: 2023 - 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
@@ -115,6 +115,14 @@ repos:
         description: Lint files to comply with the REUSE Specification
         stages: [commit]
 
+      - id: copyright-lint
+        name: copyright-lint
+        entry: scripts/copyright-lint.sh
+        language: script
+        pass_filenames: true
+        description: Check if copyright information is correct
+        stages: [commit]
+
       - id: commit-verify
         name: commit-verify
         entry: scripts/commit-verify.sh

scripts/copyright-lint.sh

@@ -0,0 +1,98 @@
+#!/bin/sh
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+## Try its best to get wrong copyright information.
+## Will show false positives if the copyright owner uploads code with year
+## smaller than the current year.
+
+set -eu
+
+command -v git >/dev/null ||
+  { printf '%s\n' "Missing program: git" >&2; exit 1; }
+repo_toplevel="$(git rev-parse --show-toplevel)"
+test -d "${repo_toplevel}" || exit 1
+cd "${repo_toplevel}"
+unset repo_toplevel
+./scripts/requires-program.sh reuse date
+
+case "${-}" in
+  *x*) xtrace=1;;
+  *) xtrace=0;;
+esac
+
+email="<$(git config --get user.email)>"
+year="$(date -- '+%Y')"
+fail="0"
+
+files=""
+if test -n "${1-}"; then
+  for f in "${@}"; do
+    test -f "${f}" || continue
+    test -r "${f}" || continue
+    files="${files} ${f}"
+  done
+else
+  files="$(git log --name-only --date=raw --since="${year}" --format="")"
+  files="${files} $(git diff --cached --name-only)"
+fi
+
+if test -z "${files}"; then
+  exit 0
+fi
+
+tmpdir="$(mktemp -d)"
+target="${tmpdir}/spdx"
+trap 'rm -rf -- "${tmpdir}"' EXIT INT HUP QUIT ABRT
+
+set +x
+data="$(reuse spdx)"
+printf '%s\n' "${data}" | tee -- "${target}"  >/dev/null
+test "${xtrace}" = 0 || set -x
+
+for file in ${files}; do
+  test "${xtrace}" = 0 || set -x
+  file="${file#./}"
+  set +x
+  awk -v year="${year}" -v email="${email}" -v file="${file}" -- '
+  BEGIN {
+    year_found = 0
+  }
+
+  $1 == "FileName:" {
+    sub(/^\.\//, "", $2)
+    f = ($2 == file)
+  }
+
+  ($1 == "FileCopyrightText:" || $1 == "SPDX-FileCopyrightText:") && f {
+    sub(/^(SPDX-)?FileCopyrightText:\s<text>SPDX-FileCopyrightText:\s/, "")
+    sub(/^SPDX-FileCopyrightText:\s/, "")
+    sub(/^FileCopyrightText:\s<text>/, "")
+    sub(/<\/text>$/, "")
+    if ($NF == email) {
+      found_years = $0
+      gsub(/[^0-9,-]/, "", found_years)
+      split(found_years, year_array, "[-,]")
+      for (i in year_array) {
+        if (year_array[i] + 0 >= year) {
+          year_found = 1
+          break
+        }
+      }
+    }
+  }
+
+  END {
+    if (year_found != 1) {
+      message = file ": " found_years ": outdated copyright year: " email
+      print message > "/dev/stderr"
+      exit 1
+    }
+  }' "${target}" || fail=1
+done
+
+if test "${fail}" = "1"; then
+  exit 1
+fi