fix(agent): check for existing branch before creating

Amp-Thread-ID:
https://ampcode.com/threads/T-79499d9e-f4f4-40de-893c-524c32a45483
Co-authored-by: Amp <amp@ampcode.com>

1 files changed, 14 insertions, 8 deletions

diff --git a/Omni/Agent/Worker.hs b/Omni/Agent/Worker.hs
index 59d576f..d201234 100644
--- a/Omni/Agent/Worker.hs
+++ b/Omni/Agent/Worker.hs
@@ -67,15 +67,21 @@ processTask worker task = do
   if currentBranch == taskBranch
     then Log.info ["worker", "resuming branch", taskBranch]
     else do
-      -- Determine base branch from dependencies
-      baseBranch <- findBaseBranch repo task
-      if baseBranch /= "live"
+      exists <- Git.branchExists repo taskBranch
+      if exists
         then do
-          Log.info ["worker", "basing", taskBranch, "on", baseBranch]
-          Git.checkout repo baseBranch
-        else Log.info ["worker", "basing", taskBranch, "on live"]
-
-      Git.createBranch repo taskBranch
+          Log.info ["worker", "switching to existing branch", taskBranch]
+          Git.checkout repo taskBranch
+        else do
+          -- Determine base branch from dependencies
+          baseBranch <- findBaseBranch repo task
+          if baseBranch /= "live"
+            then do
+              Log.info ["worker", "basing", taskBranch, "on", baseBranch]
+              Git.checkout repo baseBranch
+            else Log.info ["worker", "basing", taskBranch, "on live"]
+
+          Git.createBranch repo taskBranch
 
   -- Run Amp
   exitCode <- runAmp repo task