Merge pull request #59 from Flow-IPC/polish

The on-release-upload-tarball-etc-to-release part of workflow is not idempotent, as it will fail 2nd time (e.g., manually triggered) after succeeding the first time, even though other parts of workflow would still be useful in some cases. Now it checks for presence of the tarball before uploading tarball (else does not do it); same with zip.

.github/workflows/main.yml

@@ -1068,7 +1068,7 @@ jobs:
       id: doc_check_in
       if: success() && (!cancelled()) && (github.ref == 'refs/heads/main')
       run: |
-        # (`main` branch only) Check-in generated documentation directly into source control.
+        # Check-in generated documentation directly into source control.
         echo 'generated/ docs have been added or replaced locally; mirroring this into checked-in tree.'
         # These values informally recommended in:
         #   https://github.com/actions/checkout#push-a-commit-using-the-built-in-token
@@ -1151,21 +1151,38 @@ jobs:
         zip -r $ZIP_NAME $REPO --exclude '*/.git/*' '*/.git'
         # Soon we will need the upload URL, but unfortunately github.event.release.upload_url is only auto-populated
         # on `release` trigger; whereas we want to be triggerable manually on `push` to tag v* (so a superset
-        # of `release` trigger).  So we must figure it out via API call.
+        # of `release` trigger).  So we must figure it out via API call.  Also, if workflow is invoked a 2nd (etc.)
+        # time after succeeding once, then asset might already be attached to Release; then that upload will fail.
+        # There is still utility in invoking us manually to, say, signal the web site to re-update; so we do not
+        # want to overall-fail in that case.  So detect that situation with another API call.
         RELEASE_DATA=`curl -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
                            -H 'Accept: application/vnd.github.v3+json' \
                            https://api.github.com/repos/Flow-IPC/$REPO/releases/tags/v$VERSION`
         echo "For release [v$VERSION]: release-data API request yielded: [$RELEASE_DATA]."
         UPLOAD_URL=`echo $RELEASE_DATA | jq -r .upload_url | sed 's/{.*}$//'`
         echo "For release [v$VERSION]: upload-URL was computed to be: [$UPLOAD_URL]."
-        curl --fail-with-body -X POST \
-             -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
-             -H 'Content-Type: application/gzip' -H "Content-Length: $(wc -c < $TGZ_NAME)" \
-             --data-binary @$TGZ_NAME "$UPLOAD_URL?name=$TGZ_NAME"
-        curl --fail-with-body -X POST \
-             -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
-             -H 'Content-Type: application/zip' -H "Content-Length: $(wc -c < $ZIP_NAME)" \
-             --data-binary @$ZIP_NAME "$UPLOAD_URL?name=$ZIP_NAME"
+        ASSETS_URL=`echo $RELEASE_DATA | jq -r .assets_url'`
+        echo "For release [v$VERSION]: assets-URL was computed to be: [$ASSETS_URL]."
+        ASSET_NAMES=`curl -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
+                          -H 'Accept: application/vnd.github.v3+json' \
+                          $ASSETS_URL \
+                     | jq -r '.[].name'`
+        if echo "$ASSET_NAMES" | grep -q "^\Q$TGZ_NAME\E$"; then
+          echo "Asset named [$TGZ_NAME] is already attached to Release; upload would fail; skipping."
+        else
+          curl --fail-with-body -X POST \
+               -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
+               -H 'Content-Type: application/gzip' -H "Content-Length: $(wc -c < $TGZ_NAME)" \
+               --data-binary @$TGZ_NAME "$UPLOAD_URL?name=$TGZ_NAME"
+        fi
+        if echo "$ASSET_NAMES" | grep -q "^\Q$ZIP_NAME\E$"; then
+          echo "Asset named [$ZIP_NAME] is already attached to Release; upload would fail; skipping."
+        else
+          curl --fail-with-body -X POST \
+               -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
+               -H 'Content-Type: application/zip' -H "Content-Length: $(wc -c < $ZIP_NAME)" \
+               --data-binary @$ZIP_NAME "$UPLOAD_URL?name=$ZIP_NAME"
+        fi
 
     - name: (On release creation only) Signal Pages about release (web site should update)
       if: success() && (!cancelled()) && startsWith(github.ref, 'refs/tags/v')