From 4e4c264fbcb138555b28023c920765fe5ff865d5 Mon Sep 17 00:00:00 2001
From: Mark Ridgwell <credfeto@users.noreply.github.com>
Date: Mon, 15 Jun 2026 09:36:28 +0100
Subject: [PATCH] fix: skip rebase in git/fetch when upstream branch no longer
 exists
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After git fetch --prune removes a stale remote tracking ref, an
unconditional git rebase fails with "fatal: invalid upstream" when the
current branch was tracking that deleted branch. Guard both rebase calls
with git rev-parse --verify '@{upstream}' so they are skipped (with an
info message) rather than causing a fatal error.

Closes #681

Prompt: hey, fetch needs fixing... → No pending changes in working folder. Rebasing...
fatal: invalid upstream 'refs/remotes/origin/feature/issue-408-optimise-project-checks'

✗ Could not rebase /home/markr/work/funfair/funfair-build-check
---
 git/fetch | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/git/fetch b/git/fetch
index 84e6e7f4..771b6814 100755
--- a/git/fetch
+++ b/git/fetch
@@ -40,9 +40,14 @@ do
 
   if [ -z "$REPO_STATUS" ]
   then
-    info "No pending changes in working folder. Rebasing..."
-    git -C "$CURRENT_DIR" rebase 2>&1 || die "Could not rebase ${CURRENT_DIR}"
-    git -C "$CURRENT_DIR" rebase --abort > /dev/null 2>&1
+    if git -C "$CURRENT_DIR" rev-parse --verify '@{upstream}' > /dev/null 2>&1
+    then
+      info "No pending changes in working folder. Rebasing..."
+      git -C "$CURRENT_DIR" rebase 2>&1 || die "Could not rebase ${CURRENT_DIR}"
+      git -C "$CURRENT_DIR" rebase --abort > /dev/null 2>&1
+    else
+      info "No valid upstream for current branch. Skipping rebase."
+    fi
   else
     info "Pending changes in working folder. Skipping rebase."
   fi
@@ -63,8 +68,13 @@ do
       then
         info "Switching to ${DEFAULT_BRANCH} branch..."
         git -C "$CURRENT_DIR" checkout "$DEFAULT_BRANCH" 2>&1 || die "Could not switch to ${DEFAULT_BRANCH} in ${CURRENT_DIR}"
-        git -C "$CURRENT_DIR" rebase 2>&1 || die "Could not rebase ${DEFAULT_BRANCH} in ${CURRENT_DIR}"
-        git -C "$CURRENT_DIR" rebase --abort > /dev/null 2>&1
+        if git -C "$CURRENT_DIR" rev-parse --verify '@{upstream}' > /dev/null 2>&1
+        then
+          git -C "$CURRENT_DIR" rebase 2>&1 || die "Could not rebase ${DEFAULT_BRANCH} in ${CURRENT_DIR}"
+          git -C "$CURRENT_DIR" rebase --abort > /dev/null 2>&1
+        else
+          info "No valid upstream for ${DEFAULT_BRANCH}. Skipping rebase."
+        fi
       else
         info "Pending changes in working folder. Skipping switch to ${DEFAULT_BRANCH}."
       fi