From e42dc4075ff263f2e910a36d42fbc024b275f4db Mon Sep 17 00:00:00 2001
From: Shun Kakinoki <shunkakinoki@gmail.com>
Date: Mon, 12 Jan 2026 12:11:08 +0000
Subject: [PATCH 1/3] feat(dotfiles-updater): skip build/switch when no changes
 detected

Only run install.sh (make build && make switch) when there are actual
git changes from origin/main. This avoids unnecessary rebuilds during
the periodic 3hr update cycle.
---
 .../services/dotfiles-updater/update.sh        | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/home-manager/services/dotfiles-updater/update.sh b/home-manager/services/dotfiles-updater/update.sh
index d2d4705c4..38042f8e7 100755
--- a/home-manager/services/dotfiles-updater/update.sh
+++ b/home-manager/services/dotfiles-updater/update.sh
@@ -10,8 +10,24 @@ if [ "$(git rev-parse --abbrev-ref HEAD)" != "main" ]; then
   exit 0
 fi
 
-# Fetch and pull latest changes
+# Store current commit hash before fetching
+CURRENT_COMMIT=$(git rev-parse HEAD)
+
+# Fetch latest changes
 git fetch origin main
+
+# Get the latest remote commit
+REMOTE_COMMIT=$(git rev-parse origin/main)
+
+# Check if there are any changes
+if [ "$CURRENT_COMMIT" = "$REMOTE_COMMIT" ]; then
+  echo "No changes detected (current: ${CURRENT_COMMIT:0:8}). Skipping build and switch."
+  exit 0
+fi
+
+echo "Changes detected: ${CURRENT_COMMIT:0:8} -> ${REMOTE_COMMIT:0:8}"
+
+# Reset to latest
 git reset --hard origin/main
 
 # Run the install script

From 7306027d02e37c5d9cd669e1beeea86fd7da7122 Mon Sep 17 00:00:00 2001
From: Shun Kakinoki <shunkakinoki@gmail.com>
Date: Mon, 12 Jan 2026 12:12:55 +0000
Subject: [PATCH 2/3] test(dotfiles-updater): add tests for change detection

Add ShellSpec tests to verify:
- Current commit is stored before fetch
- Remote commit is retrieved after fetch
- Commits are compared to detect changes
- Appropriate messages are logged for both cases
---
 spec/dotfiles_updater_spec.sh | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/spec/dotfiles_updater_spec.sh b/spec/dotfiles_updater_spec.sh
index 27353836c..71b7fe0ef 100644
--- a/spec/dotfiles_updater_spec.sh
+++ b/spec/dotfiles_updater_spec.sh
@@ -50,6 +50,34 @@ The output should include 'git reset --hard origin/main'
 End
 End
 
+Describe 'change detection'
+It 'stores current commit before fetching'
+When run bash -c "grep 'CURRENT_COMMIT=\$(git rev-parse HEAD)' '$SCRIPT'"
+The output should include 'CURRENT_COMMIT=$(git rev-parse HEAD)'
+End
+
+It 'gets remote commit after fetching'
+When run bash -c "grep 'REMOTE_COMMIT=\$(git rev-parse origin/main)' '$SCRIPT'"
+The output should include 'REMOTE_COMMIT=$(git rev-parse origin/main)'
+End
+
+It 'compares commits to detect changes'
+When run bash -c "grep 'CURRENT_COMMIT.*=.*REMOTE_COMMIT' '$SCRIPT'"
+The output should include 'CURRENT_COMMIT'
+The output should include 'REMOTE_COMMIT'
+End
+
+It 'skips build when no changes detected'
+When run bash -c "grep 'No changes detected' '$SCRIPT'"
+The output should include 'No changes detected'
+End
+
+It 'logs when changes are detected'
+When run bash -c "grep 'Changes detected' '$SCRIPT'"
+The output should include 'Changes detected'
+End
+End
+
 Describe 'installation'
 It 'runs install.sh after update'
 When run bash -c "grep './install.sh' '$SCRIPT'"

From b4dd1d8b1b8585e0a153db207c92a577f8ff89a2 Mon Sep 17 00:00:00 2001
From: Shun Kakinoki <shunkakinoki@gmail.com>
Date: Mon, 12 Jan 2026 12:22:43 +0000
Subject: [PATCH 3/3] fix(tests): disable SC2016 for literal string assertions

ShellCheck complains about unexpanded expressions in single quotes,
but these are intentional literal string matches in test assertions.
---
 spec/dotfiles_updater_spec.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/spec/dotfiles_updater_spec.sh b/spec/dotfiles_updater_spec.sh
index 71b7fe0ef..2f3d6eddc 100644
--- a/spec/dotfiles_updater_spec.sh
+++ b/spec/dotfiles_updater_spec.sh
@@ -53,11 +53,13 @@ End
 Describe 'change detection'
 It 'stores current commit before fetching'
 When run bash -c "grep 'CURRENT_COMMIT=\$(git rev-parse HEAD)' '$SCRIPT'"
+# shellcheck disable=SC2016
 The output should include 'CURRENT_COMMIT=$(git rev-parse HEAD)'
 End
 
 It 'gets remote commit after fetching'
 When run bash -c "grep 'REMOTE_COMMIT=\$(git rev-parse origin/main)' '$SCRIPT'"
+# shellcheck disable=SC2016
 The output should include 'REMOTE_COMMIT=$(git rev-parse origin/main)'
 End