From 13115fee7decb71d453a93b7ec70c9542671e5b0 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sun, 25 Aug 2024 02:57:35 +0800
Subject: [PATCH 1/4] brew.sh: fix handling of dirty git repo

We cache the output of `git describe`, but we don't check whether the
cached value is valid.

This fixes that.
---
 Library/Homebrew/brew.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 314f683033..242e7eacea 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -457,7 +457,9 @@ fi
 if [[ -n "${GIT_REVISION}" ]]
 then
   GIT_DESCRIBE_CACHE_FILE="${GIT_DESCRIBE_CACHE}/${GIT_REVISION}"
-  if [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]]
+  # Pass `--` to guard against `git` being confused by a file named `HEAD`.
+  if "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff-index --quiet --exit-code HEAD -- 2>/dev/null &&
+     [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]]
   then
     GIT_DESCRIBE_CACHE_HOMEBREW_VERSION="$(cat "${GIT_DESCRIBE_CACHE_FILE}")"
     if [[ -n "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" && "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" != *"-dirty" ]]

From 58ea96583fb7547d4dc87ca8faf0a1450a4cedcc Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sun, 25 Aug 2024 03:54:40 +0800
Subject: [PATCH 2/4] brew.sh: use `read` instead of `cat`

This will be slightly more efficient since it can be done in-process.
---
 Library/Homebrew/brew.sh | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 242e7eacea..9c0be7cbdc 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -387,7 +387,7 @@ fi
 # Docker image deprecation
 if [[ -f "${HOMEBREW_REPOSITORY}/.docker-deprecate" ]]
 then
-  DOCKER_DEPRECATION_MESSAGE="$(cat "${HOMEBREW_REPOSITORY}/.docker-deprecate")"
+  read -r DOCKER_DEPRECATION_MESSAGE <"${HOMEBREW_REPOSITORY}/.docker-deprecate"
   if [[ -n "${GITHUB_ACTIONS}" ]]
   then
     echo "::warning::${DOCKER_DEPRECATION_MESSAGE}" >&2
@@ -443,13 +443,13 @@ GIT_REVISION=$("${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" rev-parse HEAD 2>/d
 # safe fallback in case git rev-parse fails e.g. if this is not considered a safe git directory
 if [[ -z "${GIT_REVISION}" ]]
 then
-  GIT_HEAD="$(cat "${HOMEBREW_REPOSITORY}/.git/HEAD" 2>/dev/null)"
+  read -r GIT_HEAD <"${HOMEBREW_REPOSITORY}/.git/HEAD" 2>/dev/null
   if [[ "${GIT_HEAD}" == "ref: refs/heads/master" ]]
   then
-    GIT_REVISION="$(cat "${HOMEBREW_REPOSITORY}/.git/refs/heads/master" 2>/dev/null)"
+    read -r GIT_REVISION <"${HOMEBREW_REPOSITORY}/.git/refs/heads/master" 2>/dev/null
   elif [[ "${GIT_HEAD}" == "ref: refs/heads/stable" ]]
   then
-    GIT_REVISION="$(cat "${HOMEBREW_REPOSITORY}/.git/refs/heads/stable" 2>/dev/null)"
+    read -r GIT_REVISION <"${HOMEBREW_REPOSITORY}/.git/refs/heads/stable" 2>/dev/null
   fi
   unset GIT_HEAD
 fi
@@ -461,7 +461,7 @@ then
   if "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff-index --quiet --exit-code HEAD -- 2>/dev/null &&
      [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]]
   then
-    GIT_DESCRIBE_CACHE_HOMEBREW_VERSION="$(cat "${GIT_DESCRIBE_CACHE_FILE}")"
+    read -r GIT_DESCRIBE_CACHE_HOMEBREW_VERSION <"${GIT_DESCRIBE_CACHE_FILE}"
     if [[ -n "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" && "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" != *"-dirty" ]]
     then
       HOMEBREW_VERSION="${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}"

From a597a1eecbe4b8996be048ef73d7c267bcb4a51a Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Wed, 28 Aug 2024 18:58:27 +0800
Subject: [PATCH 3/4] Reverse order of `if` conditional

Checking for readability is a cheaper operation that `git diff-index`.
---
 Library/Homebrew/brew.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 9c0be7cbdc..cace4206ee 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -458,8 +458,8 @@ if [[ -n "${GIT_REVISION}" ]]
 then
   GIT_DESCRIBE_CACHE_FILE="${GIT_DESCRIBE_CACHE}/${GIT_REVISION}"
   # Pass `--` to guard against `git` being confused by a file named `HEAD`.
-  if "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff-index --quiet --exit-code HEAD -- 2>/dev/null &&
-     [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]]
+  if [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]] &&
+     "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff-index --quiet HEAD -- 2>/dev/null
   then
     read -r GIT_DESCRIBE_CACHE_HOMEBREW_VERSION <"${GIT_DESCRIBE_CACHE_FILE}"
     if [[ -n "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" && "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" != *"-dirty" ]]

From b63ecff52c0048825144a38dd60adb7858c16666 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Wed, 28 Aug 2024 19:21:50 +0800
Subject: [PATCH 4/4] brew.sh: use `git diff` instead of `git diff-index`

---
 Library/Homebrew/brew.sh | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index cace4206ee..5ac659e1fc 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -457,9 +457,7 @@ fi
 if [[ -n "${GIT_REVISION}" ]]
 then
   GIT_DESCRIBE_CACHE_FILE="${GIT_DESCRIBE_CACHE}/${GIT_REVISION}"
-  # Pass `--` to guard against `git` being confused by a file named `HEAD`.
-  if [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]] &&
-     "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff-index --quiet HEAD -- 2>/dev/null
+  if [[ -r "${GIT_DESCRIBE_CACHE_FILE}" ]] && "${HOMEBREW_GIT}" -C "${HOMEBREW_REPOSITORY}" diff --quiet --no-ext-diff 2>/dev/null
   then
     read -r GIT_DESCRIBE_CACHE_HOMEBREW_VERSION <"${GIT_DESCRIBE_CACHE_FILE}"
     if [[ -n "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" && "${GIT_DESCRIBE_CACHE_HOMEBREW_VERSION}" != *"-dirty" ]]