ci: use built in system to select the release branch

.github/workflows/release_github.yml

@@ -11,10 +11,6 @@ on:
           - patch
           - minor
           - major
-      release_branch:
-        description: "Branch to use for releasing."
-        type: string
-        default: "develop"
 
 permissions:
   contents: write
@@ -28,6 +24,16 @@ jobs:
         shell: bash -l {0}
 
     steps:
+      - name: Release from develop branch by default
+        if: ${{ github.ref_name }} == 'main'
+        run: |
+          echo "RELEASE_BRANCH=develop" >> $GITHUB_ENV
+
+      - name: Release from specified branch
+        if: ${{ github.ref_name }} != 'main'
+        run: |
+          echo "RELEASE_BRANCH=${{ github.ref_name }}" >> $GITHUB_ENV
+
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
@@ -42,7 +48,7 @@ jobs:
       - name: Merge changes into main
         run: |
           git switch main
-          git merge ${{ github.event.inputs.release_branch }} --no-ff --no-commit
+          git merge $RELEASE_BRANCH --no-ff --no-commit
           git merge --continue
 
       - name: Bump version
@@ -92,8 +98,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           echo "-- searching for associated PR"
-          branch_name=${{ github.event.inputs.release_branch }}
-          pr_number=$(gh pr list --head $branch_name --json number --jq '.[0].number')
+          pr_number=$(gh pr list --head $RELEASE_BRANCH --json number --jq '.[0].number')
           if [ -n "$pr_number" ]; then
             echo "-- closing PR #$pr_number"
             gh pr close $pr_number
@@ -109,9 +114,9 @@ jobs:
 
       - name: Delete release branch other than main or develop
         run: |
-          if [[ ${{ github.event.inputs.release_branch}} != "main" && ${{ github.event.inputs.release_branch}} != "develop" ]]; then
-            echo "-- deleting branch '${{ github.event.inputs.release_branch }}'"
-            git push origin -d ${{ github.event.inputs.release_branch }}
+          if [[ $RELEASE_BRANCH != "main" && $RELEASE_BRANCH != "develop" ]]; then
+            echo "-- deleting branch '$RELEASE_BRANCH'"
+            git push origin -d $RELEASE_BRANCH
           else
-            echo "-- branch '${{ github.event.inputs.release_branch}}' will not be deleted from remote"
+            echo "-- branch '$RELEASE_BRANCH' will not be deleted from remote"
           fi

README.dev.md

@@ -134,13 +134,16 @@ We use [prettier](https://prettier.io/) for formatting most other files. If you
    - if everything goes well, this PR will automatically be closed after the draft release is created.
 1. Navigate to [Draft Github Release](https://github.com/EIT-ALIVE/eitprocessing/actions/workflows/release_github.yml)
    on the [Actions](https://github.com/EIT-ALIVE/eitprocessing/actions) tab.
-2. On the right hand side, you can select the level increase (patch, minor, or major) and which branch to release from.
-   - if released from a different branch than `develop`, then the workflow will attempt to merge the changes into develop
-     as well. If succesfull, the release branch will be deleted from the remote repository.
-   - [follow semantic versioning conventions](https://semver.org/) to chose the level increase:
+2. On the right hand side, you can select the level increase ("patch", "minor", or "major") and which branch to release from.
+   - [Follow semantic versioning conventions](https://semver.org/) to chose the level increase:
      - `patch`: when backward compatible bug fixes were made
      - `minor`: when functionality was added in a backward compatible manner
      - `major`: when API-incompatible changes have been made
+   - Note that if you choose `main` (the default shown) as the release branch, this will be re-defaulted to develop
+     instead. To release from `main` directly, you must follow the [manual release
+     instructions](#manually-create-a-release) below.
+   - If the release branch is not `develop`, the workflow will attempt to merge the changes into develop as well. If
+     succesfull, the release branch will be deleted from the remote repository.
 3. Visit [Actions](https://github.com/EIT-ALIVE/eitprocessing/actions) tab to check whether everything went as expected.
 4. Navigate to the [Releases](https://github.com/EIT-ALIVE/eitprocessing/releases) tab and click on the newest draft
    release that was just generated.