Post-0.12.1 release CI updates (#4873)

### What

- Fixes #4763
- Fixes #4366

Updates to scripts/workflows:
- [x] Ensure `sync_release_assets.py` fails if some requested asset is
not found
- This has tripped people up multiple times. The assets were not synced,
but the job also didn't fail.
- [x] Automate GitHub release
- The `0.12.1` tag must be created on the release commit, otherwise the
asset sync won't be able to find the assets.

Failure fixes:
- [x] Fix `latest` branch update
- We have both a `latest` tag and a `latest` branch, and git doesn't
know what the destination of
`push release-x.y.z:latest` should be. The fix is to specify explicitly
    `refs/heads/release-x.y.z:refs/heads/latest`
  - Also deleted the tag because it was really out of date.
- [x] Fix post-release version bump
- The job was checking out the default branch and then it ran into merge
conflicts in the `git pull`, solution should be to check out the release
commit and skipping the `git pull`

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[app.rerun.io](https://app.rerun.io/pr/4873/index.html)
* Using examples from latest `main` build:
[app.rerun.io](https://app.rerun.io/pr/4873/index.html?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[app.rerun.io](https://app.rerun.io/pr/4873/index.html?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/4873)
- [Docs
preview](https://rerun.io/preview/5db0e755be09fa2642987305a049681e79a29a7c/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/5db0e755be09fa2642987305a049681e79a29a7c/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

.github/workflows/release.yml

@@ -296,14 +296,60 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          fetch-depth: 0
           ref: ${{ needs.version.outputs.release-commit }}
 
       - name: Update latest branch
         shell: bash
         run: |
           git fetch
           git checkout ${{ github.ref_name }}
-          git push --force origin ${{ github.ref_name }}:latest
+          git push --force origin refs/heads${{ github.ref_name }}:refs/heads/latest
+
+  github-release:
+    name: "GitHub Release"
+    if: inputs.release-type == 'final'
+    needs:
+      [
+        version,
+        update-docs,
+        publish-crates,
+        publish-wheels,
+        publish-web,
+        publish-rerun_c,
+        publish-rerun-cli,
+        publish-npm,
+      ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ needs.version.outputs.release-commit }}
+          token: ${{ secrets.RERUN_BOT_TOKEN }}
+
+      - name: Release tag
+        env:
+          GH_TOKEN: ${{ secrets.RERUN_BOT_TOKEN }}
+        run: |
+          version="${{ needs.version.outputs.final }}"
+          git tag $version
+          git push origin $version
+          gh release create $version --verify-tag --draft --title $version
+
+      - name: Create comment
+        env:
+          GH_TOKEN: ${{ secrets.RERUN_BOT_TOKEN }}
+        run: |
+          pr_number=$(gh pr view --json number | jq '.number')
+          version="${{ needs.version.outputs.final }}"
+
+          cat <<EOF > comment-body.txt
+          GitHub release draft: [$version](https://github.com/rerun-io/rerun/releases/tag/$version)
+          EOF
+
+          gh pr comment $pr_number --body-file comment-body.txt
 
   post-release-version-bump:
     name: "Post-Release Version Bump"
@@ -318,12 +364,15 @@ jobs:
         publish-rerun_c,
         publish-rerun-cli,
         publish-npm,
+        github-release,
       ]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          fetch-depth: 0
+          ref: ${{ needs.version.outputs.release-commit }}
           token: ${{ secrets.RERUN_BOT_TOKEN }}
 
       - uses: actions/setup-node@v4
@@ -361,7 +410,6 @@ jobs:
           git config --global user.name "rerun-bot"
           git config --global user.email "[email protected]"
           git commit -am "Bump versions to ${{ steps.update-version.outputs.version }}"
-          git pull --rebase
           git push
 
   comment-artifact-links:

scripts/ci/sync_release_assets.py

@@ -49,16 +49,23 @@ def fetch_binary_assets(
     bucket = gcs.bucket("rerun-builds")
 
     commit_short = commit[:7]
-    print(f"Fetching binary assets for #{commit_short}…")
-    print(f"  - wheels: {do_wheels}")
-    print(f"  - C libs: {do_rerun_c}")
-    print(f"  - C++ uber SDK: {do_rerun_cpp_sdk}")
-    print(f"  - CLI (Viewer): {do_rerun_cli}")
+    print(f"Fetching the following binary assets for #{commit_short}:")
+    if do_wheels:
+        print("  - Python wheels")
+    if do_rerun_c:
+        print("  - C libs")
+    if do_rerun_cpp_sdk:
+        print("  - C++ uber SDK")
+    if do_rerun_cli:
+        print("  - CLI (Viewer)")
+
+    all_found = True
 
     # Python wheels
     if do_wheels:
+        found = False
         wheel_blobs = list(bucket.list_blobs(prefix=f"commit/{commit_short}/wheels"))
-        for blob in [bucket.get_blob(blob.name) for blob in wheel_blobs if blob.name.endswith(".whl")]:
+        for blob in (bucket.get_blob(blob.name) for blob in wheel_blobs if blob.name.endswith(".whl")):
             if blob is not None and blob.name is not None:
                 name = blob.name.split("/")[-1]
 
@@ -76,10 +83,14 @@ def fetch_binary_assets(
                 #
                 # if "win_amd64" in name:
                 #     name = f"rerun_sdk-{tag}-x86_64-pc-windows-msvc.whl"
-
-                print(f"    Found Python wheel: {name} ")
+                print(f"Found Python wheels: {name}")
+                found = True
                 assets[name] = blob
 
+        if not found:
+            all_found = False
+            print("Python wheels not found")
+
     # rerun_c
     if do_rerun_c:
         rerun_c_blobs = [
@@ -102,19 +113,25 @@ def fetch_binary_assets(
         ]
         for name, blob in rerun_c_blobs:
             if blob is not None:
-                print(f"    Found Rerun C library: {name}")
+                print(f"Found Rerun C library: {name}")
                 assets[name] = blob
+            else:
+                all_found = False
+                print(f"Rerun C library {name} not found")
 
     # rerun_cpp_sdk
     if do_rerun_cpp_sdk:
         rerun_cpp_sdk_blob = bucket.get_blob(f"commit/{commit_short}/rerun_cpp_sdk.zip")
         for blob in [rerun_cpp_sdk_blob]:
             if blob is not None and blob.name is not None:
                 name = blob.name.split("/")[-1]
-                print(f"    Found Rerun cross-platform bundle: {name}")
+                print(f"Found Rerun cross-platform bundle: {name}")
                 assets[name] = blob
                 # NOTE: Want a versioned one too.
                 assets[f"rerun_cpp_sdk-{tag}-multiplatform.zip"] = blob
+            else:
+                all_found = False
+                print("Rerun cross-platform bundle not found")
 
     # rerun-cli
     if do_rerun_cli:
@@ -138,8 +155,14 @@ def fetch_binary_assets(
         ]
         for name, blob in rerun_cli_blobs:
             if blob is not None:
-                print(f"    Found Rerun CLI binary: {name}")
+                print(f"Found Rerun CLI binary: {name}")
                 assets[name] = blob
+            else:
+                all_found = False
+                print(f"Rerun CLI binary {name} not found")
+
+    if not all_found:
+        raise Exception("some requested assets were not found")
 
     return assets
 
@@ -148,7 +171,7 @@ def remove_release_assets(release: GitRelease):
     print("Removing pre-existing release assets…")
 
     for asset in release.get_assets():
-        print(f"    Removing {asset.name}…")
+        print(f"Removing {asset.name}…")
         asset.delete_asset()
 
 
@@ -162,7 +185,7 @@ def update_release_assets(release: GitRelease, assets: Assets):
         # the upload in all kinds of unexpected ways (including SSL errors!) depending on the versions
         # of your reqwest & pygithub dependencies.
         blob_raw_size = len(blob_contents)
-        print(f"    Uploading {name} ({blob_raw_size} bytes)…")
+        print(f"Uploading {name} ({blob_raw_size} bytes)…")
         release.upload_asset_from_memory(
             blob_contents,
             blob_raw_size,