From 25f101a1a6d31da52ac2b7644e3a083eeeb487b8 Mon Sep 17 00:00:00 2001
From: Garry Tan <garrytan@gmail.com>
Date: Fri, 14 Aug 2026 19:26:31 -0700
Subject: [PATCH] fix(setup): register the SessionStart hook with a bash prefix
 on Windows
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Windows can't execute an extensionless bash script directly — registering
the bare gstack-session-update path made the hook pop the "Select an app"
dialog on every session start (or silently never run), so team-mode
auto-upgrade was dead on Windows installs. Companion to the hooks'
spawn-bin routing: same defect class at the registration site.

Contributed by @NikhileshNanduri (PR #1813; VERSION/CHANGELOG collateral
stripped).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 setup                               | 9 ++++++++-
 test/setup-windows-fallback.test.ts | 8 ++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/setup b/setup
index c28b44a71..49f05ffc2 100755
--- a/setup
+++ b/setup
@@ -1293,7 +1293,14 @@ rm -f /tmp/gstack-latest-version
 
 # 10. Team mode: register/unregister SessionStart hook
 SETTINGS_HOOK="$SOURCE_GSTACK_DIR/bin/gstack-settings-hook"
-HOOK_CMD="$SOURCE_GSTACK_DIR/bin/gstack-session-update"
+# On Windows (Git Bash / MSYS2 / Cygwin), extensionless scripts can't be
+# launched directly by the OS — the file-association dialog appears instead.
+# Prefix with 'bash' so Claude Code's hook runner invokes Git Bash explicitly.
+if [ "$IS_WINDOWS" -eq 1 ]; then
+  HOOK_CMD="bash $SOURCE_GSTACK_DIR/bin/gstack-session-update"
+else
+  HOOK_CMD="$SOURCE_GSTACK_DIR/bin/gstack-session-update"
+fi
 
 if [ "$TEAM_MODE" -eq 1 ]; then
   "$GSTACK_CONFIG" set auto_upgrade true 2>/dev/null || true
diff --git a/test/setup-windows-fallback.test.ts b/test/setup-windows-fallback.test.ts
index cc04fbbd7..142bb7912 100644
--- a/test/setup-windows-fallback.test.ts
+++ b/test/setup-windows-fallback.test.ts
@@ -55,6 +55,14 @@ describe('setup: _link_or_copy invariant (D7)', () => {
     const fnBody = SETUP_SRC.slice(fnStart, fnEnd);
     expect(fnBody).toContain('_print_windows_copy_note_once');
   });
+
+  test('SessionStart HOOK_CMD is prefixed with bash on Windows (D7-session-hook)', () => {
+    const hookStart = SETUP_SRC.indexOf('# 10. Team mode: register/unregister SessionStart hook');
+    const hookEnd = SETUP_SRC.indexOf('\nif [ "$TEAM_MODE" -eq 1 ]', hookStart);
+    const hookSection = SETUP_SRC.slice(hookStart, hookEnd);
+    expect(hookSection).toContain('IS_WINDOWS');
+    expect(hookSection).toContain('bash $SOURCE_GSTACK_DIR/bin/gstack-session-update');
+  });
 });
 
 // Behavior matrix uses Unix `ln -snf` semantics in the IS_WINDOWS=0 cells.