git-prompt.sh: allow to hide prompt for ignored pwd

Optionally set __git_ps1 to display nothing when present working
directory is ignored, triggered by the new environment variable
GIT_PS1_HIDE_IF_PWD_IGNORED. This environment variable may be
overridden on any repository by setting bash.hideIfPwdIgnored to
"false". In the absence of GIT_PS1_HIDE_IF_PWD_IGNORED this change
has no effect.

Many people manage e.g. dotfiles in their home directory with git.
This causes the prompt generated by __git_ps1 to refer to that "top
level" repo while working in any descendant directory. That can be
distracting, so this patch helps one shut off that noise.

Signed-off-by: Jess Austin <jess.austin@gmail.com>
Signed-off-by: Richard Hansen <rhansen@bbn.com>
Reviewed-by: Richard Hansen <rhansen@bbn.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-prompt.sh

@@ -84,6 +84,11 @@
 # GIT_PS1_SHOWCOLORHINTS to a nonempty value. The colors are based on
 # the colored output of "git status -sb" and are available only when
 # using __git_ps1 for PROMPT_COMMAND or precmd.
+#
+# If you would like __git_ps1 to do nothing in the case when the current
+# directory is set up to be ignored by git, then set
+# GIT_PS1_HIDE_IF_PWD_IGNORED to a nonempty value. Override this on the
+# repository level by setting bash.hideIfPwdIgnored to "false".
 
 # check whether printf supports -v
 __git_printf_supports_v=
@@ -369,6 +374,14 @@ __git_ps1 ()
 	local inside_gitdir="${repo_info##*$'\n'}"
 	local g="${repo_info%$'\n'*}"
 
+	if [ "true" = "$inside_worktree" ] &&
+	   [ -n "${GIT_PS1_HIDE_IF_PWD_IGNORED-}" ] &&
+	   [ "$(git config --bool bash.hideIfPwdIgnored)" != "false" ] &&
+	   git check-ignore -q .
+	then
+		return
+	fi
+
 	local r=""
 	local b=""
 	local step=""

t/t9903-bash-prompt.sh

@@ -35,6 +35,8 @@ test_expect_success 'setup for prompt tests' '
 	git commit -m "another b2" file &&
 	echo 000 >file &&
 	git commit -m "yet another b2" file &&
+	mkdir ignored_dir &&
+	echo "ignored_dir/" >>.gitignore &&
 	git checkout master
 '
 
@@ -588,4 +590,108 @@ test_expect_success 'prompt - zsh color pc mode' '
 	test_cmp expected "$actual"
 '
 
+test_expect_success 'prompt - hide if pwd ignored - env var unset, config disabled' '
+	printf " (master)" >expected &&
+	test_config bash.hideIfPwdIgnored false &&
+	(
+		cd ignored_dir &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var unset, config disabled, pc mode' '
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER" >expected &&
+	test_config bash.hideIfPwdIgnored false &&
+	(
+		cd ignored_dir &&
+		__git_ps1 "BEFORE:" ":AFTER" &&
+		printf "%s" "$PS1" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var unset, config unset' '
+	printf " (master)" >expected &&
+	(
+		cd ignored_dir &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var unset, config unset, pc mode' '
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER" >expected &&
+	(
+		cd ignored_dir &&
+		__git_ps1 "BEFORE:" ":AFTER" &&
+		printf "%s" "$PS1" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var set, config disabled' '
+	printf " (master)" >expected &&
+	test_config bash.hideIfPwdIgnored false &&
+	(
+		cd ignored_dir &&
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var set, config disabled, pc mode' '
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER" >expected &&
+	test_config bash.hideIfPwdIgnored false &&
+	(
+		cd ignored_dir &&
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		__git_ps1 "BEFORE:" ":AFTER" &&
+		printf "%s" "$PS1" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var set, config unset' '
+	printf "" >expected &&
+	(
+		cd ignored_dir &&
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - env var set, config unset, pc mode' '
+	printf "BEFORE::AFTER" >expected &&
+	(
+		cd ignored_dir &&
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		__git_ps1 "BEFORE:" ":AFTER" &&
+		printf "%s" "$PS1" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - inside gitdir (stdout)' '
+	printf " (GIT_DIR!)" >expected &&
+	(
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		cd .git &&
+		__git_ps1 >"$actual" 2>/dev/null
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - hide if pwd ignored - inside gitdir (stderr)' '
+	printf "" >expected &&
+	(
+		GIT_PS1_HIDE_IF_PWD_IGNORED=y &&
+		cd .git &&
+		__git_ps1 >/dev/null 2>"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
 test_done