From 0496e05eb4f85b9f80f25d59e440ff4b089c5731 Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Mon, 1 Jan 2018 22:16:48 -0800
Subject: [PATCH] tg: improve handling of configured core.hooksPath

Since Git v2.9.0 there is support for a "core.hooksPath" config
item, but the implementation semantics are an abomination.

Improve the way TopGit deals with such nasties and add some
tests specifically for the evil core.hooksPath setting.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 t/t1062-hookspath.sh | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++
 tg.sh                |  63 +++++++++++++++++-
 2 files changed, 245 insertions(+), 1 deletion(-)
 create mode 100755 t/t1062-hookspath.sh

diff --git a/t/t1062-hookspath.sh b/t/t1062-hookspath.sh
new file mode 100755
index 0000000..79dbe8b
--- /dev/null
+++ b/t/t1062-hookspath.sh
@@ -0,0 +1,183 @@
+#!/bin/sh
+
+test_description='test core.hooksPath management'
+
+TEST_NO_CREATE_REPO=1
+
+. ./test-lib.sh
+
+if vcmp "$git_version" '>=' "2.9"; then
+        test_set_prereq GIT_2_9
+fi
+
+test_plan 14
+
+write_dummy_script() {
+	write_script "$@" <<\EOT
+exit 0
+EOT
+}
+
+write_dummy_file() {
+	echo "# dummy file $1" >"$1"
+}
+
+matches() {
+	eval "case \"$1\" in $2) return 0; esac"
+	return 1
+}
+
+do_mergesetup() {
+        test_might_fail tg -C "$1" update no-such-branch-name 2>&1
+}
+
+test_expect_success 'setup' '
+	mkdir _global _global/hooks insidious insidious/_global insidious/_global/hooks &&
+	ln -s _global/hooks globhookdir &&
+	ln -s . insidious/subdir &&
+	git init -q --template "$PWD/_global/hooks" --bare insidious/_global &&
+	write_dummy_script _global/hooks/pre-auto-gc &&
+	write_dummy_script _global/hooks/pre-receive &&
+	write_dummy_script _global/hooks/update &&
+	write_dummy_script _global/hooks/post-commit &&
+	write_dummy_script _global/hooks/post-receive &&
+	write_dummy_file _global/hooks/prepare-commit-msg &&
+	write_dummy_script _global/hooks/commit-msg.sh &&
+	test_create_repo r1 &&
+	test_create_repo r2 &&
+	mkdir r2/.git/hooks &&
+	test_create_repo r3 &&
+	mkdir r3/.git/hooks &&
+	(cd r3/.git/hooks && ln -s ../../../_global/hooks/* ./) &&
+	rm r3/.git/hooks/prepare-commit-msg r3/.git/hooks/commit-msg.sh &&
+	test_create_repo r4 &&
+	mkdir r4/.git/hooks &&
+	cp _global/hooks/* r4/.git/hooks/ &&
+	rm r4/.git/hooks/prepare-commit-msg r4/.git/hooks/commit-msg.sh &&
+	cp r4/.git/hooks/* insidious/_global/hooks/ &&
+	test ! -d r5 &&
+	cp -R r3 r5 &&
+	test -d r5/.git/hooks &&
+	rm r5/.git/hooks/update &&
+	test ! -d r6 &&
+	cp -R r4 r6 &&
+	test -d r6/.git/hooks &&
+	rm r6/.git/hooks/update &&
+	test ! -d r7 &&
+	cp -R r4 r7 &&
+	test -d r7/.git/hooks &&
+	echo different >> r7/.git/hooks/update &&
+	test ! -d r8 &&
+	cp -R r4 r8 &&
+	test -d r8/.git/hooks &&
+	echo notexec > r8/.git/hooks/update &&
+	chmod a-x r8/.git/hooks/update
+'
+
+test_expect_success GIT_2_9 'relative hookspath' '
+	test_config -C r2 core.hooksPath "" &&
+	bad= &&
+	for rpath in hooks .git/hooks ../_global/hooks ../../_global/hooks; do
+		git -C r2 config core.hooksPath "$rpath" &&
+		result="$(set +vx && do_mergesetup r2)" &&
+		matches "$result" "*\"ignoring non-absolute core.hooks\"[Pp]\"ath\"*" || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+
+test_expect_success GIT_2_9 'no such hookspath' '
+	test_config -C r2 core.hooksPath "" &&
+	bad= &&
+	for rpath in hooks .git/hooks ../_global/hooks ../../_global/hooks; do
+		git -C r2 config core.hooksPath "$PWD/ns1/ns2/ns3/ns4/$rpath" &&
+		result="$(set +vx && do_mergesetup r2)" &&
+		matches "$result" "*\"ignoring non-existent core.hooks\"[Pp]\"ath\"*" || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+
+test_expect_success GIT_2_9 'our absolute hooks' '
+	test_config -C r2 core.hooksPath "" &&
+	bad= &&
+	for rpath in hooks hooks/../hooks ../.git/hooks ../../r2/.git/hooks; do
+		git -C r2 config core.hooksPath "$PWD/r2/.git/$rpath" &&
+		result="$(set +vx && do_mergesetup r2)" &&
+		newcp="$(git -C r2 config core.hooksPath)" &&
+		test "$PWD/r2/.git/$rpath" = "$newcp" &&
+		! matches "$result" "*\" warning: \"*" || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+
+test_expect_success GIT_2_9 'no gratuitous hookspath' '
+	bad= &&
+	for rpath in r?; do
+		do_mergesetup $rpath >/dev/null &&
+		test_must_fail git config -C $rpath --get core.hooksPath >/dev/null || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+
+friendly="r3 r4"
+
+for repo in r?; do
+case " $friendly " in *" $repo "*);;*) continue; esac
+test_expect_success GIT_2_9 '"friendly" hookspath '"$repo" '
+	test_config -C $repo core.hooksPath "" &&
+	bad= &&
+	for gpath in _global/hooks globhookdir; do
+		rm -f "$gpath/pre-commit" &&
+		git -C $repo config core.hooksPath "$PWD/$gpath" &&
+		result="$(set +vx && do_mergesetup $repo)" &&
+		newcp="$(git -C $repo config core.hooksPath)" &&
+		test "$PWD/$gpath" != "$newcp" &&
+		test "$(cd "$PWD/$repo/.git/hooks" && pwd -P)" = "$(cd "$newcp" && pwd -P)" &&
+		! matches "$result" "*\" warning: \"*" || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+done
+
+for repo in r?; do
+case " $friendly " in *" $repo "*) continue; esac
+test_expect_success GIT_2_9 '"unfriendly" hookspath '"$repo" '
+	test_config -C $repo core.hooksPath "" &&
+	bad= &&
+	for gpath in _global/hooks globhookdir; do
+		rm -f "$gpath/pre-commit" &&
+		git -C $repo config core.hooksPath "$PWD/$gpath" &&
+		result="$(set +vx && do_mergesetup $repo)" &&
+		newcp="$(git -C $repo config core.hooksPath)" &&
+		test "$PWD/$gpath" = "$newcp" &&
+		! matches "$result" "*\" warning: \"*" || {
+			bad=1 &&
+			break
+		}
+	done &&
+	test -z "$bad"
+'
+done
+
+test_expect_success GIT_2_9 'insidious hookspath' '
+	git -C insidious/_global config core.hooksPath "$PWD/insidious/subdir/_global/hooks" &&
+	do_mergesetup insidious/_global >/dev/null &&
+	newcp="$(git -C insidious/_global config core.hooksPath)" &&
+	test "$PWD/insidious/subdir/_global/hooks" = "$newcp"
+'
+
+test_done
diff --git a/tg.sh b/tg.sh
index 458da1b..ae2de22 100644
--- a/tg.sh
+++ b/tg.sh
@@ -73,6 +73,7 @@ exec_lc_all_c()
 # any Git translations will still appear for Git commands
 awk()	{ exec_lc_all_c awk @AWK_PATH@	"$@"; }
 cat()	{ exec_lc_all_c cat cat		"$@"; }
+cmp()	{ exec_lc_all_c cmp cmp		"$@"; }
 cut()	{ exec_lc_all_c cut cut		"$@"; }
 find()	{ exec_lc_all_c find find	"$@"; }
 grep()	{ exec_lc_all_c grep grep	"$@"; }
@@ -1920,6 +1921,53 @@ setup_git_dir_is_bare()
 	fi
 }
 
+git_hooks_pat_list="\
+[a]pplypatch-ms[g] [p]re-applypatc[h] [p]ost-applypatc[h] [p]re-commi[t] \
+[p]repare-commit-ms[g] [c]ommit-ms[g] [p]ost-commi[t] [p]re-rebas[e] \
+[p]ost-checkou[t] [p]ost-merg[e] [p]re-pus[h] [p]re-receiv[e] [u]pdat[e] \
+[p]ost-receiv[e] [p]ost-updat[e] [p]ush-to-checkou[t] [p]re-auto-g[c] \
+[p]ost-rewrit[e]"
+
+# git_hooks_dir must already be set to the value of core.hooksPath which
+# exists and is an absolute path.  The first and only argument is the
+# "pwd -P" of the $git_hooks_dir directory.  If the core.hooksPath setting
+# appears to be "friendly" attempt to alter it to be an absolute path to
+# "$git_common_dir/hooks" instead.  A "friendly" core.hooksPath setting
+# points to a directory for which "$git_common_dir/hooks" already has
+# entries which are symbolic links to the same core.hooksPath items.
+# There's no POSIX readlink utility, but there is a 'cmp -s' utility so we
+# use that instead to check.  Also the "friendly" core.hooksPath must be
+# something that's recognizable as belonging to a "friendly".
+maybe_adjust_friendly_hooks_path()
+{
+	case "$1" in */_global/hooks);;*) return 0; esac
+	[ -n "$1" ] && [ -d "$1" ] && [ -d "$git_common_dir/hooks" ] || return 0
+	[ -w "$git_common_dir" ] || return 0
+	! [ -e "$git_common_dir/config" ] || {
+	[ -f "$git_common_dir/config" ] && [ -w "$git_common_dir/config" ]
+	} || return 0
+	oktoswitch=1
+	for ghook in $(cd "$1" && eval "echo $git_hooks_pat_list"); do
+		case "$ghook" in "["*) continue; esac
+		[ -x "$1/$ghook" ] &&
+		[ -f "$1/$ghook" ] || continue
+		[ -x "$git_common_dir/hooks/$ghook" ] &&
+		[ -f "$git_common_dir/hooks/$ghook" ] &&
+		cmp -s "$1/$ghook" "$git_common_dir/hooks/$ghook" || {
+			oktoswitch=
+			break
+		}
+	done
+	if [ -n "$oktoswitch" ]; then
+		# a known "friendly" was detected and the hooks match;
+		# go ahead and silently switch the path
+		! git config core.hooksPath "$git_common_dir/hooks" >/dev/null 2>&1 ||
+		git_hooks_dir="$git_common_dir/hooks"
+	fi
+	unset_ oktoswitch
+	return 0
+}
+
 setup_git_dirs()
 {
 	[ -n "$git_dir" ] || git_dir="$(git rev-parse --git-dir)"
@@ -1943,7 +1991,20 @@ setup_git_dirs()
 	if vcmp "$git_version" '>=' "2.9" && gchp="$(git config --path --get core.hooksPath 2>/dev/null)" && [ -n "$gchp" ]; then
 		case "$gchp" in
 			/[!/]*)
-				git_hooks_dir="$gchp"
+				if [ -d "$gchp" ]; then
+					# if core.hooksPath is just another name for
+					# $git_common_dir/hooks, keep referring to it
+					# by $git_common_dir/hooks
+					abscdh="$(cd "$git_common_dir" && pwd -P)/hooks"
+					abshpd="$(cd "$gchp" && pwd -P)"
+					if [ "$abshpd" != "$abscdh" ]; then
+						git_hooks_dir="$gchp"
+						maybe_adjust_friendly_hooks_path "$abshpd"
+					fi
+					unset_ abscdh abshpd
+				else
+					[ -n "$1" ] || warn "ignoring non-existent core.hooksPath: $gchp"
+				fi
 				;;
 			*)
 				[ -n "$1" ] || warn "ignoring non-absolute core.hooksPath: $gchp"
-- 
2.11.4.GIT