Move deb pkg version stuff to separate script

.github/workflows/package.yml

@@ -40,22 +40,7 @@ jobs:
           UBUNTU_VERSION: ${{ matrix.UBUNTU_VERSION }}
         run: |
           cd source
-          DPKG_VERSION=$(dpkg-parsechangelog -S version)
-          DPKG_DISTRIBUTION=$(dpkg-parsechangelog -S distribution)
-          GIT_SEPARATOR='+'
-          DCH_BACKPORT=
-          if [[ $DPKG_DISTRIBUTION == UNRELEASED ]]; then
-            GIT_SEPARATOR='~0+'
-          elif [[ $DPKG_DISTRIBUTION != $UBUNTU_CODENAME ]]; then
-            DCH_BACKPORT="~$UBUNTU_VERSION"
-          fi
-          GIT_DESCRIBE=$(git describe --tags)
-          GIT_TAG=$(git describe --tags --abbrev=0)
-          GIT_EXTRA=${GIT_DESCRIBE#${GIT_TAG}}
-          GIT_EXTRA=${GIT_EXTRA/-/$GIT_SEPARATOR}
-          GIT_EXTRA=${GIT_EXTRA//-/.}
-          DCH_VERSION="${DPKG_VERSION}${DCH_BACKPORT}${GIT_EXTRA}"
-          echo "DCH_VERSION=${DCH_VERSION}" | tee -a $GITHUB_ENV
+          eval "$(./dch_version.sh | tee -a "${GITHUB_ENV}")"
           dch --newversion "${DCH_VERSION}" --force-bad-version --distribution "${UBUNTU_CODENAME}" "Automatic Build"
 
       - name: Cleanup .github directory

dch_version.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# This is a tool to convert a semver 2.0.0 compatible version to a format which
+# is compatible with both debian packaging tools and - after the transformations
+# applied in debian pybuild - python PEP 440. It should generate the same python
+# package version as is generated by setuptools_scm's "post-release" scheme.
+GIT_TAG=$(git describe --tags --abbrev=0 "$@")
+GIT_DESCRIBE=$(git describe --tags --long --dirty=.d$(date +%Y%m%d) "$@")
+GIT_EXTRA="${GIT_DESCRIBE#${GIT_TAG}}"
+GIT_TAG="${GIT_TAG//-/'~'}"
+GIT_TAG="${GIT_TAG//alpha./alpha}"
+GIT_TAG="${GIT_TAG//beta./beta}"
+GIT_TAG="${GIT_TAG//rc./rc}"
+DCH_VERSION="${GIT_TAG}"
+
+GIT_EXTRA="${GIT_EXTRA#-}"
+GIT_DISTANCE="${GIT_EXTRA%%-*}"
+GIT_BUILD="${GIT_EXTRA#${GIT_DISTANCE}-}"
+GIT_BUILD_HASH="${GIT_BUILD%%.*}"
+if [[ $GIT_DISTANCE == 0 ]]; then
+    GIT_BUILD="${GIT_BUILD#${GIT_BUILD_HASH}}"
+    GIT_BUILD="${GIT_BUILD#.}"
+fi
+if [[ -n $GIT_BUILD ]]; then
+    DCH_VERSION+=".post${GIT_DISTANCE}+${GIT_BUILD}"
+elif [[ $GIT_DISTANCE != 0 ]]; then
+    DCH_VERSION+=".post${GIT_DISTANCE}"
+fi
+
+echo "DCH_VERSION=${DCH_VERSION@Q}"