diff --git a/tools/publisher/src/subcommand/fix_manifests.rs b/tools/publisher/src/subcommand/fix_manifests.rs
index 4faa2f1bdb04b604da73e7dcba96b289f10693bd..75e8a4d8fd23194373f889e442eb062e8359bf95 100644
--- a/tools/publisher/src/subcommand/fix_manifests.rs
+++ b/tools/publisher/src/subcommand/fix_manifests.rs
@@ -53,13 +53,19 @@ async fn read_manifests(fs: Fs, manifest_paths: Vec<PathBuf>) -> Result<Vec<Mani
 fn package_versions(manifests: &[Manifest]) -> Result<BTreeMap<String, Version>> {
     let mut versions = BTreeMap::new();
     for manifest in manifests {
-        let name = manifest.metadata["package"]["name"]
-            .as_str()
+        let name = manifest
+            .metadata
+            .get("package")
+            .and_then(|package| package.get("name"))
+            .and_then(|name| name.as_str())
             .ok_or_else(|| {
                 anyhow::Error::msg(format!("{:?} is missing a package name", manifest.path))
             })?;
-        let version = manifest.metadata["package"]["version"]
-            .as_str()
+        let version = manifest
+            .metadata
+            .get("package")
+            .and_then(|package| package.get("version"))
+            .and_then(|name| name.as_str())
             .ok_or_else(|| {
                 anyhow::Error::msg(format!("{:?} is missing a package version", manifest.path))
             })?;