Check for existing tag

.github/workflows/release-version.yml

@@ -42,23 +42,28 @@ jobs:
   validation:
     runs-on: ubuntu-latest
     outputs:
-      GDEXT_PUBLISHED_VERSION: ${{ steps.interpret-tag-version.outputs.GDEXT_PUBLISHED_VERSION }}
+      GDEXT_PUBLISHED_VERSION: ${{ steps.parse-crate-version.outputs.GDEXT_PUBLISHED_VERSION }}
     steps:
       - uses: actions/checkout@v4
 
-      # sed: https://unix.stackexchange.com/a/589584
-      - name: "Interpret tag version"
-        id: interpret-tag-version
+      - name: "Parse crate version from Cargo.toml"
+        id: parse-crate-version
         run: |
-          #version=$(echo "$GITHUB_REF" | sed -n "s#refs/tags/v\(.*\)#\1#p")
-          version="0.1.0" # DEBUG
-          [ -z "$version" ] && {
-            printf "\n::error::Failed to parse '$GITHUB_REF'.\n"
+          crateVer=$(grep '^version' godot/Cargo.toml | sed -E 's/^version = "(.*)"$/\1/')
+          if [[ -z "$crateVer" ]]; then
+              echo "::error::Failed to parse crate version from Cargo.toml."
+              exit 1
+          fi
+          
+          # Check if tag exists.
+          git fetch --tags
+          git tag -l | grep -q "^v$version$" && {
+            echo "::error::Tag 'v$version' already exists."
             exit 2
           }
           
-          echo "Published version: $version"
-          echo "GDEXT_PUBLISHED_VERSION=$version" >> $GITHUB_OUTPUT
+          echo "GDEXT_PUBLISHED_VERSION=$crateVer" >> $GITHUB_OUTPUT
+          echo "Validated version: $crateVer"
 
       - name: "Verify that Cargo.toml versions match ${{ steps.interpret-tag-version.outputs.GDEXT_PUBLISHED_VERSION }}"
         run: |