From e6932fb96c33b20ec9d687c8febee0abf083a571 Mon Sep 17 00:00:00 2001
From: Greg Price <greg@zulip.com>
Date: Sun, 8 Dec 2024 18:19:11 -0800
Subject: [PATCH] tools [nfc]: Factor out a function to find the Flutter tree

---
 tools/check      |  6 +-----
 tools/lib/git.sh | 10 ++++++++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tools/check b/tools/check
index a5e5962cb2..6a0cdb35d0 100755
--- a/tools/check
+++ b/tools/check
@@ -434,8 +434,6 @@ describe_git_head() {
 }
 
 print_header() {
-    local flutter_executable flutter_tree
-
     echo "Test command: ${orig_cmdline}"
 
     echo "Time now: $(date --utc +'%F %T %z')"
@@ -445,9 +443,7 @@ print_header() {
     # We avoid `flutter --version` because, weirdly, when run in a
     # GitHub Actions step it takes about 30 seconds.  (The first time;
     # it's fast subsequent times.)  That's even after `flutter precache`.
-    flutter_executable=$(readlink -f "$(type -p flutter)")
-    flutter_tree=${flutter_executable%/bin/flutter}
-    describe_git_head "flutter/flutter" "${flutter_tree}"/.git
+    describe_git_head "flutter/flutter" "$(flutter_tree)"/.git
 
     dart --version
 }
diff --git a/tools/lib/git.sh b/tools/lib/git.sh
index 1fa254e1a4..cff123b371 100644
--- a/tools/lib/git.sh
+++ b/tools/lib/git.sh
@@ -90,3 +90,13 @@ git_base_commit() {
 git_changed_files() {
     git diff --name-only --diff-filter=d "$@"
 }
+
+# The root of the active Flutter tree.
+#
+# (This isn't strictly about Git, but in practice we use it
+# mainly for `git --git-dir`.)
+flutter_tree() {
+    local flutter_executable
+    flutter_executable=$(readlink -f "$(type -p flutter)")
+    echo "${flutter_executable%/bin/flutter}"
+}