diff --git a/.github/workflows/extension_bump.yml b/.github/workflows/extension_bump.yml
index 4f9ee444ac..ff903eb63d 100644
--- a/.github/workflows/extension_bump.yml
+++ b/.github/workflows/extension_bump.yml
@@ -39,8 +39,9 @@ jobs:
       run: |
         CURRENT_VERSION="$(sed -n 's/^version = \"\(.*\)\"/\1/p' < extension.toml | tr -d '[:space:]')"
 
-        if [[ -n "$PR_PARENT_REF" ]]; then
-            git checkout "$PR_PARENT_REF"
+        if [[ "${{ github.event_name }}" == "pull_request" ]]; then
+            PR_FORK_POINT="$(git merge-base --fork-point main)"
+            git checkout "$PR_FORK_POINT"
         elif BRANCH_PARENT_SHA="$(git merge-base origin/main origin/zed-zippy-autobump)"; then
             git checkout "$BRANCH_PARENT_SHA"
         else
@@ -54,8 +55,6 @@ jobs:
             echo "version_changed=true" >> "$GITHUB_OUTPUT"
 
         echo "current_version=${CURRENT_VERSION}" >> "$GITHUB_OUTPUT"
-      env:
-        PR_PARENT_REF: ${{ github.head_ref }}
     outputs:
       version_changed: ${{ steps.compare-versions-check.outputs.version_changed }}
       current_version: ${{ steps.compare-versions-check.outputs.current_version }}
diff --git a/.github/workflows/extension_tests.yml b/.github/workflows/extension_tests.yml
index 3bc3d43b05..ed35a05424 100644
--- a/.github/workflows/extension_tests.yml
+++ b/.github/workflows/extension_tests.yml
@@ -114,8 +114,9 @@ jobs:
       run: |
         CURRENT_VERSION="$(sed -n 's/^version = \"\(.*\)\"/\1/p' < extension.toml | tr -d '[:space:]')"
 
-        if [[ -n "$PR_PARENT_REF" ]]; then
-            git checkout "$PR_PARENT_REF"
+        if [[ "${{ github.event_name }}" == "pull_request" ]]; then
+            PR_FORK_POINT="$(git merge-base --fork-point main)"
+            git checkout "$PR_FORK_POINT"
         elif BRANCH_PARENT_SHA="$(git merge-base origin/main origin/zed-zippy-autobump)"; then
             git checkout "$BRANCH_PARENT_SHA"
         else
@@ -129,8 +130,6 @@ jobs:
             echo "version_changed=true" >> "$GITHUB_OUTPUT"
 
         echo "current_version=${CURRENT_VERSION}" >> "$GITHUB_OUTPUT"
-      env:
-        PR_PARENT_REF: ${{ github.head_ref }}
     - name: extension_tests::verify_version_did_not_change
       run: |
         if [[ ${{ steps.compare-versions-check.outputs.version_changed }} == "true" && "${{ github.event_name }}" == "pull_request" && "${{ github.event.pull_request.user.login }}" != "zed-zippy[bot]" ]] ; then
diff --git a/tooling/xtask/src/tasks/workflows/extension_bump.rs b/tooling/xtask/src/tasks/workflows/extension_bump.rs
index e06e50fa6e..bdc25f766e 100644
--- a/tooling/xtask/src/tasks/workflows/extension_bump.rs
+++ b/tooling/xtask/src/tasks/workflows/extension_bump.rs
@@ -150,8 +150,9 @@ pub(crate) fn compare_versions() -> (Step<Run>, StepOutput, StepOutput) {
     r#"
         CURRENT_VERSION="$({VERSION_CHECK})"
 
-        if [[ -n "$PR_PARENT_REF" ]]; then
-            git checkout "$PR_PARENT_REF"
+        if [[ "${{{{ github.event_name }}}}" == "pull_request" ]]; then
+            PR_FORK_POINT="$(git merge-base --fork-point main)"
+            git checkout "$PR_FORK_POINT"
         elif BRANCH_PARENT_SHA="$(git merge-base origin/main origin/zed-zippy-autobump)"; then
             git checkout "$BRANCH_PARENT_SHA"
         else
@@ -167,7 +168,6 @@ pub(crate) fn compare_versions() -> (Step<Run>, StepOutput, StepOutput) {
         echo "current_version=${{CURRENT_VERSION}}" >> "$GITHUB_OUTPUT"
         "#
     })
-    .add_env(("PR_PARENT_REF", Context::github().head_ref()))
     .id("compare-versions-check");
 
     let version_changed = StepOutput::new(&check_needs_bump, "version_changed");