chore(license): avoid sourcing PKGBUILD in check subcommand

We don't actually need any data from the package, except the pkgbase
which is exclusively used during logging. Simply grep the pkgbase name
and use the path during early code path issues.

Component: pkgctl license check

src/commitpkg.in

@@ -123,9 +123,10 @@ fi
 needsversioning=()
 
 if [[ ! -e REUSE.toml || ! -e LICENSE || ! -d LICENSES ]]; then
-	error "package doesn't have proper licensing information, set it up using:"
+	# TODO: Make this a hard failure in the future after packagers have had
+	# some time to add licenses to all packages.
+	warning "package doesn't have proper licensing information, set it up using:"
 	msg2 'pkgctl license setup'
-	exit 1
 else
 	pkgctl license check
 	needsversioning+=(REUSE.toml LICENSE LICENSES/*)

src/lib/license/check.sh

@@ -94,19 +94,19 @@ pkgctl_license_check() {
 		pushd "${path}" >/dev/null
 
 		if [[ ! -f PKGBUILD ]]; then
-			msg_error "${BOLD}${pkgbase}:${ALL_OFF} no PKGBUILD found"
+			msg_error "${BOLD}${path}:${ALL_OFF} no PKGBUILD found"
 			return 1
 		fi
 
-		# reset common PKGBUILD variables
-		unset pkgbase
-
-		# shellcheck source=contrib/makepkg/PKGBUILD.proto
-		if ! . ./PKGBUILD; then
-			msg_error "${BOLD}${pkgbase}:${ALL_OFF} failed to source PKGBUILD"
+		if [[ ! -f .SRCINFO ]]; then
+			msg_error "${BOLD}${path}:${ALL_OFF} no .SRCINFO found"
+			return 1
+		fi
+
+		if ! pkgbase=$(grep --max-count=1 --extended-regexp "pkgbase = (.+)" .SRCINFO | awk '{print $3}'); then
+			msg_error "${BOLD}${path}:${ALL_OFF} pkgbase not found in .SRCINFO"
 			return 1
 		fi
-		pkgbase=${pkgbase:-$pkgname}
 
 		if [[ ! -e LICENSE ]]; then
 			msg_error "${BOLD}${pkgbase}:${ALL_OFF} is missing the LICENSE file"