feat: define publishable changelog sections

lib/changelog.sh

@@ -20,3 +20,48 @@ changelog_section() {
     found { body = 1; print }
   ' "$1"
 }
+
+# changelog_section_problem <file> <version>
+#
+# Print the first reason a version section cannot be published. Unreleased is
+# a work-in-progress template, so its headings may deliberately be empty.
+# A printed problem returns 1; silence returns 0.
+changelog_section_problem() {
+  local file="$1" ver="$2" notes problem
+
+  if ! awk -v ver="$ver" '/^## / && $2 == ver { found = 1; exit } END { exit !found }' "$file"; then
+    printf "no section for '%s'\n" "$ver"
+    return 1
+  fi
+
+  [ "$ver" = "Unreleased" ] && return 0
+
+  notes="$(changelog_section "$file" "$ver")"
+  if ! printf '%s\n' "$notes" | awk '/^[[:space:]]*[-*][[:space:]]/ { found = 1; exit } END { exit !found }'; then
+    printf "section '%s' has no entries — a heading is not an entry\n" "$ver"
+    return 1
+  fi
+
+  problem="$(
+    printf '%s\n' "$notes" | awk '
+      /^### / {
+        if (heading != "" && !entry) {
+          reported = 1
+          print heading
+          exit
+        }
+        heading = $0
+        entry = 0
+        next
+      }
+      heading != "" && /^[[:space:]]*[-*][[:space:]]/ { entry = 1 }
+      END {
+        if (!reported && heading != "" && !entry) print heading
+      }
+    '
+  )"
+  if [ -n "$problem" ]; then
+    printf "section '%s' has an empty heading: '%s'\n" "$ver" "$problem"
+    return 1
+  fi
+}

test/changelog.test.sh

@@ -57,6 +57,77 @@ check "date-less version heading parses" 0 "" assert_section 0.4.0 '- A date-les
 check "empty stamped section returns empty output" 0 "" assert_section 0.5.0 ""
 check "missing section returns empty output" 0 "" assert_section 9.9.9 ""
 
+PROBLEM_FIXTURE="$TMP/CHANGELOG.problems.md"
+assert_problem() {
+  local version="$1" expected_status="$2" expected="$3"
+  check "predicate: $version / $expected" "$expected_status" "$expected" \
+    changelog_section_problem "$PROBLEM_FIXTURE" "$version"
+}
+
+cat >"$PROBLEM_FIXTURE" <<'EOF'
+# Changelog
+
+## Unreleased
+
+### Added
+
+### Changed
+
+### Fixed
+
+## 1.0.0
+
+- Flat dash entry.
+
+## 1.1.0
+
+* Flat star entry.
+
+## 1.2.0
+
+### Fixed
+
+- Fixed entry.
+
+## 1.3.0
+
+### Added
+
+- Added entry.
+
+### Changed
+
+* Changed entry.
+
+### Fixed
+
+- Fixed entry.
+
+## 1.4.0
+
+## 1.5.0
+
+### Added
+
+## 1.6.0
+
+### Added
+
+### Fixed
+
+- Fixed entry.
+EOF
+
+assert_problem Unreleased 0 ""
+assert_problem 1.0.0 0 ""
+assert_problem 1.1.0 0 ""
+assert_problem 1.2.0 0 ""
+assert_problem 1.3.0 0 ""
+assert_problem 1.4.0 1 "section '1.4.0' has no entries — a heading is not an entry"
+assert_problem 1.5.0 1 "section '1.5.0' has no entries — a heading is not an entry"
+assert_problem 1.6.0 1 "section '1.6.0' has an empty heading: '### Added'"
+assert_problem 9.9.9 1 "no section for '9.9.9'"
+
 WRAPPER="$ROOT/bin/changelog-section"
 check "wrapper publishes the requested body" 0 "The seven-oh entry" "$WRAPPER" 0.7.0 "$FIXTURE"
 check "wrapper refuses an empty section" 1 "no section for '0.5.0'" "$WRAPPER" 0.5.0 "$FIXTURE"