feat(version): support combiner source for version check commands

This allows more flexibility and chaining by being able to define
multiple sources per pkgbase and chain them together to achieve the
final result. This may also be helpful to combine multiple from/to
patterns into a chain to achieve the final pkgver to compare against.

To utilize the combiner source, the `pkgbase` section must be declared
as the combiner source. Additionally, individual sections should be
added using a quoted table key consisting of the `pkgbase` followed by
the stage name, separated by double colons.
For example: `["sudo:stage1"]`.

Fixes #216

Component: pkgctl version check
Signed-off-by: Levente Polyak <anthraxx@archlinux.org>

doc/man/pkgctl-version.1.asciidoc

@@ -39,6 +39,14 @@ placed in the `$XDG_CONFIG_HOME`/nvchecker` directory. This keyfile is
 used for providing the necessary authentication tokens required for
 accessing the GitHub or GitLab API.
 
+Combiner Source
+---------------
+
+To utilize the combiner source, the `pkgbase` section must be declared as the
+combiner source. Additionally, individual sections should be added using a
+quoted table key consisting of the `pkgbase` followed by the stage name,
+separated by double colons. For example: `["sudo:stage1"]`.
+
 Options
 -------
 

src/lib/version/check.sh

@@ -304,6 +304,11 @@ get_upstream_version() {
 		return 1
 	fi
 
+	if ! output=$(jq --raw-output --exit-status 'select(.name == "'"${pkgbase}"'")' <<< "${output}"); then
+		printf "failed to select pkgbase result from output"
+		return 1
+	fi
+
 	if ! upstream_version=$(jq --raw-output --exit-status '.version' <<< "${output}"); then
 		printf "failed to select version from result"
 		return 1
@@ -346,7 +351,7 @@ nvchecker_check_config() {
 	fi
 
 	# check if the config contains any section other than pkgbase
-	if [[ -n ${pkgbase} ]] && property=$(grep --max-count=1 --perl-regexp "^\\[(?!\"?${pkgbase//+/\\+}\"?\\]).+\\]" < "${config}"); then
+	if [[ -n ${pkgbase} ]] && property=$(grep --max-count=1 --perl-regexp "^\\[(?!\"?${pkgbase//+/\\+}(:.+)?\"?\\]).+\\]" < "${config}"); then
 		printf "non-pkgbase section not supported in %s: %s" "${config}" "${property}"
 		return 1
 	fi