Don't introduce more failure

Co-Authored-By: Max <max@zed.dev>

crates/extension_host/src/wasm_host/wit.rs

@@ -78,13 +78,18 @@ impl Extension {
         version: SemanticVersion,
         component: &Component,
     ) -> Result<Self> {
-        // Note: The release channel can be used to stage a new version of the extension API.
-        let allow_latest_version = match release_channel {
-            ReleaseChannel::Dev | ReleaseChannel::Nightly => true,
-            ReleaseChannel::Stable | ReleaseChannel::Preview => false,
-        };
-
-        if allow_latest_version && version >= latest::MIN_VERSION {
+        if version >= latest::MIN_VERSION {
+            // Note: The release channel can be used to stage a new version of the extension API.
+            // We always allow the latest in tests so that the extension tests pass on release branches.
+            let allow_latest_version = match release_channel {
+                ReleaseChannel::Dev | ReleaseChannel::Nightly => true,
+                ReleaseChannel::Stable | ReleaseChannel::Preview => cfg!(test),
+            };
+            if !allow_latest_version {
+                Err(anyhow!(
+                    "unreleased versions of the extension API can only be used on development builds of Zed"
+                ))?;
+            }
             let extension =
                 latest::Extension::instantiate_async(store, component, latest::linker())
                     .await

crates/zed/RELEASE_CHANNEL

@@ -1 +1 @@
-dev
+preview

script/determine-release-channel

@@ -15,7 +15,7 @@ version=$(script/get-crate-version zed)
 channel=$(cat crates/zed/RELEASE_CHANNEL)
 echo "Publishing version: ${version} on release channel ${channel}"
 echo "RELEASE_CHANNEL=${channel}" >> $GITHUB_ENV
-echo "RELEASE_VERSION="${version}" >> $GITHUB_ENV
+echo "RELEASE_VERSION=${version}" >> $GITHUB_ENV
 
 expected_tag_name=""
 case ${channel} in