[RFC] advice: refuse to output if stderr not TTY

Documentation/config/advice.txt

@@ -1,8 +1,11 @@
 advice.*::
 	These variables control various optional help messages designed to
-	aid new users.  When left unconfigured, Git will give the message
-	alongside instructions on how to squelch it.  You can tell Git
-	that you do not need the help message by setting these to `false`:
+	aid new users. These are only output to `stderr` when it is a
+	terminal.
++
+When left unconfigured, Git will give the message alongside instructions
+on how to squelch it.  You can tell Git that you do not need the help
+message by setting these to `false`:
 +
 --
 	addEmbeddedRepo::

advice.c

@@ -133,7 +133,9 @@ int advice_enabled(enum advice_type type)
 	static int globally_enabled = -1;
 
 	if (globally_enabled < 0)
-		globally_enabled = git_env_bool(GIT_ADVICE_ENVIRONMENT, 1);
+		globally_enabled = git_env_bool(GIT_ADVICE_ENVIRONMENT, -1);
+	if (globally_enabled < 0)
+		globally_enabled = isatty(2);
 	if (!globally_enabled)
 		return 0;
 

t/lib-httpd.sh

@@ -265,7 +265,7 @@ test_http_push_nonff () {
 		echo "changed" > path2 &&
 		git commit -a -m path2 --amend &&
 
-		test_must_fail git push -v origin >output 2>&1 &&
+		test_env GIT_ADVICE=1 test_must_fail git push -v origin >output 2>&1 &&
 		(
 			cd "$REMOTE_REPO" &&
 			echo "$HEAD" >expect &&

t/t0018-advice.sh

@@ -8,7 +8,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
-test_expect_success 'advice should be printed when config variable is unset' '
+test_expect_success TTY 'advice should be printed when config variable is unset' '
 	cat >expect <<-\EOF &&
 	hint: This is a piece of advice
 	hint: Disable this message with "git config advice.nestedTag false"
@@ -17,7 +17,7 @@ test_expect_success 'advice should be printed when config variable is unset' '
 	test_cmp expect actual
 '
 
-test_expect_success 'advice should be printed when config variable is set to true' '
+test_expect_success TTY 'advice should be printed when config variable is set to true' '
 	cat >expect <<-\EOF &&
 	hint: This is a piece of advice
 	EOF
@@ -26,13 +26,13 @@ test_expect_success 'advice should be printed when config variable is set to tru
 	test_cmp expect actual
 '
 
-test_expect_success 'advice should not be printed when config variable is set to false' '
+test_expect_success TTY 'advice should not be printed when config variable is set to false' '
 	test_config advice.nestedTag false &&
 	test-tool advise "This is a piece of advice" 2>actual &&
 	test_must_be_empty actual
 '
 
-test_expect_success 'advice should not be printed when --no-advice is used' '
+test_expect_success TTY 'advice should not be printed when --no-advice is used' '
 	q_to_tab >expect <<-\EOF &&
 	On branch trunk
 
@@ -54,7 +54,7 @@ test_expect_success 'advice should not be printed when --no-advice is used' '
 	test_cmp expect actual
 '
 
-test_expect_success 'advice should not be printed when GIT_ADVICE is set to false' '
+test_expect_success TTY 'advice should not be printed when GIT_ADVICE is set to false' '
 	q_to_tab >expect <<-\EOF &&
 	On branch trunk
 
@@ -76,6 +76,8 @@ test_expect_success 'advice should not be printed when GIT_ADVICE is set to fals
 	test_cmp expect actual
 '
 
+# This test also verifies that GIT_ADVICE=1 ignores the requirement
+# that stderr is a terminal.
 test_expect_success 'advice should be printed when GIT_ADVICE is set to true' '
 	q_to_tab >expect <<-\EOF &&
 	On branch trunk
@@ -99,4 +101,10 @@ test_expect_success 'advice should be printed when GIT_ADVICE is set to true' '
 	test_cmp expect actual
 '
 
+test_expect_success 'advice should not be printed when stderr is not a terminal' '
+	test_config advice.nestedTag true &&
+	test-tool advise "This is a piece of advice" 2>actual &&
+	test_must_be_empty actual
+'
+
 test_done

t/t1092-sparse-checkout-compatibility.sh

@@ -411,10 +411,10 @@ test_expect_success 'add outside sparse cone' '
 	run_on_sparse mkdir folder1 &&
 	run_on_sparse ../edit-contents folder1/a &&
 	run_on_sparse ../edit-contents folder1/newfile &&
-	test_sparse_match test_must_fail git add folder1/a &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/a &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
-	test_sparse_match test_must_fail git add folder1/newfile &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/newfile &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/newfile
 '
@@ -466,13 +466,13 @@ test_expect_success 'status/add: outside sparse cone' '
 	test_sparse_match git status --porcelain=v2 &&
 
 	# Adding the path outside of the sparse-checkout cone should fail.
-	test_sparse_match test_must_fail git add folder1/a &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/a &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_all_match git add --refresh folder1/a &&
 	test_must_be_empty sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
-	test_sparse_match test_must_fail git add folder1/new &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/new &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/new &&
 	test_sparse_match git add --sparse folder1/a &&
@@ -1018,7 +1018,7 @@ test_expect_success 'merge with conflict outside cone' '
 	test_all_match git status --porcelain=v2 &&
 
 	# 2. Add the file with conflict markers
-	test_sparse_match test_must_fail git add folder1/a &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/a &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_all_match git add --sparse folder1/a &&
@@ -1027,7 +1027,7 @@ test_expect_success 'merge with conflict outside cone' '
 	# 3. Rename the file to another sparse filename and
 	#    accept conflict markers as resolved content.
 	run_on_all mv folder2/a folder2/z &&
-	test_sparse_match test_must_fail git add folder2 &&
+	test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder2 &&
 	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder2/z &&
 	test_all_match git add --sparse folder2 &&
@@ -1058,7 +1058,7 @@ test_expect_success 'cherry-pick/rebase with conflict outside cone' '
 		# NEEDSWORK: Even though the merge conflict removed the
 		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
 		# warn that this is a problematic add.
-		test_sparse_match test_must_fail git add folder1/a &&
+		test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder1/a &&
 		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 		test_sparse_unstaged folder1/a &&
 		test_all_match git add --sparse folder1/a &&
@@ -1070,7 +1070,7 @@ test_expect_success 'cherry-pick/rebase with conflict outside cone' '
 		# outside of the sparse-checkout cone and does not match an
 		# existing index entry with the SKIP_WORKTREE bit cleared.
 		run_on_all mv folder2/a folder2/z &&
-		test_sparse_match test_must_fail git add folder2 &&
+		test_env GIT_ADVICE=1 test_sparse_match test_must_fail git add folder2 &&
 		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 		test_sparse_unstaged folder2/z &&
 		test_all_match git add --sparse folder2 &&
@@ -2341,7 +2341,7 @@ test_expect_success 'advice.sparseIndexExpanded' '
 	git -C sparse-index sparse-checkout set deep/deeper1 &&
 	mkdir -p sparse-index/deep/deeper2/deepest &&
 	touch sparse-index/deep/deeper2/deepest/bogus &&
-	git -C sparse-index status 2>err &&
+	GIT_ADVICE=1 git -C sparse-index status 2>err &&
 	grep "The sparse index is expanding to a full index" err
 '
 

t/t2020-checkout-detach.sh

@@ -175,7 +175,7 @@ test_expect_success 'tracking count is accurate after orphan check' '
 	git config branch.child.remote . &&
 	git config branch.child.merge refs/heads/main &&
 	git checkout child^ &&
-	git checkout child >stdout &&
+	GIT_ADVICE=1 git checkout child >stdout &&
 	test_cmp expect stdout &&
 
 	git checkout --detach child >stdout &&
@@ -251,15 +251,17 @@ test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not as
 	# Various ways of *not* asking for ellipses
 
 	sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
-	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 1st_detach actual &&
 
-	GIT_PRINT_SHA1_ELLIPSIS="no" git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1  GIT_PRINT_SHA1_ELLIPSIS="no" git -c 'core.abbrev=12' \
+		checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 2nd_detach actual &&
 
-	GIT_PRINT_SHA1_ELLIPSIS= git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 GIT_PRINT_SHA1_ELLIPSIS= git -c 'core.abbrev=12' \
+		checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 3rd_detach actual &&
 
@@ -270,17 +272,17 @@ test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not as
 	check_not_detached &&
 
 	# Make no mention of the env var at all
-	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 1st_detach actual &&
 
 	GIT_PRINT_SHA1_ELLIPSIS='nope' &&
-	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 2nd_detach actual &&
 
 	GIT_PRINT_SHA1_ELLIPSIS=nein &&
-	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 3rd_detach actual &&
 
@@ -333,15 +335,18 @@ test_expect_success 'describe_detached_head does print SHA-1 ellipsis when asked
 	# Various ways of asking for ellipses...
 	# The user can just use any kind of quoting (including none).
 
-	GIT_PRINT_SHA1_ELLIPSIS=yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 GIT_PRINT_SHA1_ELLIPSIS=yes git -c 'core.abbrev=12' \
+		checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 1st_detach actual &&
 
-	GIT_PRINT_SHA1_ELLIPSIS=Yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 GIT_PRINT_SHA1_ELLIPSIS=Yes git -c 'core.abbrev=12' \
+		checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 2nd_detach actual &&
 
-	GIT_PRINT_SHA1_ELLIPSIS=YES git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	GIT_ADVICE=1 GIT_PRINT_SHA1_ELLIPSIS=YES git -c 'core.abbrev=12' \
+		checkout HEAD^ >actual 2>&1 &&
 	check_detached &&
 	test_cmp 3rd_detach actual &&
 

t/t2024-checkout-dwim.sh

@@ -103,11 +103,12 @@ test_expect_success 'when arg matches multiple remotes, do not fallback to inter
 test_expect_success 'checkout of branch from multiple remotes fails with advice' '
 	git checkout -B main &&
 	test_might_fail git branch -D foo &&
-	test_must_fail git checkout foo 2>stderr &&
+	test_env GIT_ADVICE=1 test_must_fail git checkout foo 2>stderr &&
 	test_branch main &&
 	status_uno_is_clean &&
 	test_grep "^hint: " stderr &&
-	test_must_fail git -c advice.checkoutAmbiguousRemoteBranchName=false \
+	test_env GIT_ADVICE=1 test_must_fail git \
+		-c advice.checkoutAmbiguousRemoteBranchName=false \
 		checkout foo 2>stderr &&
 	test_branch main &&
 	status_uno_is_clean &&

t/t2060-switch.sh

@@ -34,13 +34,13 @@ test_expect_success 'switch and detach' '
 '
 
 test_expect_success 'suggestion to detach' '
-	test_must_fail git switch main^{commit} 2>stderr &&
+	test_env GIT_ADVICE=1 test_must_fail git switch main^{commit} 2>stderr &&
 	grep "try again with the --detach option" stderr
 '
 
 test_expect_success 'suggestion to detach is suppressed with advice.suggestDetachingHead=false' '
 	test_config advice.suggestDetachingHead false &&
-	test_must_fail git switch main^{commit} 2>stderr &&
+	test_env GIT_ADVICE=1 test_must_fail git switch main^{commit} 2>stderr &&
 	! grep "try again with the --detach option" stderr
 '
 

t/t2204-add-ignored.sh

@@ -30,7 +30,7 @@ for i in ign dir/ign dir/sub dir/sub/*ign sub/file sub sub/*
 do
 	test_expect_success "complaints for ignored $i" '
 		rm -f .git/index &&
-		test_must_fail git add "$i" 2>err &&
+		test_env GIT_ADVICE=1 test_must_fail git add "$i" 2>err &&
 		git ls-files "$i" >out &&
 		test_must_be_empty out
 	'
@@ -41,7 +41,7 @@ do
 
 	test_expect_success "complaints for ignored $i with unignored file" '
 		rm -f .git/index &&
-		test_must_fail git add "$i" file 2>err &&
+		test_env GIT_ADVICE=1 test_must_fail git add "$i" file 2>err &&
 		git ls-files "$i" >out &&
 		test_must_be_empty out
 	'
@@ -56,7 +56,7 @@ do
 		rm -f .git/index &&
 		(
 			cd dir &&
-			test_must_fail git add "$i" 2>err &&
+			test_env GIT_ADVICE=1 test_must_fail git add "$i" 2>err &&
 			git ls-files "$i" >out &&
 			test_must_be_empty out
 		)
@@ -76,7 +76,7 @@ do
 		rm -f .git/index &&
 		(
 			cd sub &&
-			test_must_fail git add "$i" 2>err &&
+			test_env GIT_ADVICE=1 test_must_fail git add "$i" 2>err &&
 			git ls-files "$i" >out &&
 			test_must_be_empty out
 		)

t/t2400-worktree-add.sh

@@ -436,7 +436,7 @@ test_wt_add_orphan_hint () {
 		git init repo &&
 		(cd repo && test_commit commit) &&
 		git -C repo switch --orphan noref &&
-		test_must_fail git -C repo worktree add $opts foobar/ 2>actual &&
+		test_env GIT_ADVICE=1 test_must_fail git -C repo worktree add $opts foobar/ 2>actual &&
 		! grep "error: unknown switch" actual &&
 		grep "hint: If you meant to create a worktree containing a new unborn branch" actual &&
 		if [ $use_branch -eq 1 ]
@@ -983,7 +983,7 @@ test_dwim_orphan () {
 			fi &&
 			if [ "$outcome" = "infer" ]
 			then
-				git $dashc_args worktree add $args 2>actual &&
+				GIT_ADVICE=1 git $dashc_args worktree add $args 2>actual &&
 				if [ $use_quiet -eq 1 ]
 				then
 					test_must_be_empty actual
@@ -992,7 +992,7 @@ test_dwim_orphan () {
 				fi
 			elif [ "$outcome" = "no_infer" ]
 			then
-				git $dashc_args worktree add $args 2>actual &&
+				GIT_ADVICE=1 git $dashc_args worktree add $args 2>actual &&
 				if [ $use_quiet -eq 1 ]
 				then
 					test_must_be_empty actual
@@ -1001,11 +1001,11 @@ test_dwim_orphan () {
 				fi
 			elif [ "$outcome" = "fetch_error" ]
 			then
-				test_must_fail git $dashc_args worktree add $args 2>actual &&
+				test_env GIT_ADVICE=1 test_must_fail git $dashc_args worktree add $args 2>actual &&
 				grep "$fetch_error_text" actual
 			elif [ "$outcome" = "fatal_orphan_bad_combo" ]
 			then
-				test_must_fail git $dashc_args worktree add $args 2>actual &&
+				test_env GIT_ADVICE=1 test_must_fail git $dashc_args worktree add $args 2>actual &&
 				if [ $use_quiet -eq 1 ]
 				then
 					! grep "$info_text" actual
@@ -1015,7 +1015,7 @@ test_dwim_orphan () {
 				grep "$bad_combo_regex" actual
 			elif [ "$outcome" = "warn_bad_head" ]
 			then
-				test_must_fail git $dashc_args worktree add $args 2>actual &&
+				test_env GIT_ADVICE=1 test_must_fail git $dashc_args worktree add $args 2>actual &&
 				if [ $use_quiet -eq 1 ]
 				then
 					grep "$invalid_ref_regex" actual &&

t/t3200-branch.sh

@@ -1161,7 +1161,7 @@ test_expect_success 'avoid ambiguous track and advise' '
 	hint: different remotes'\'' fetch refspecs map into different
 	hint: tracking namespaces.
 	EOF
-	test_must_fail git branch all1 main 2>actual &&
+	test_env GIT_ADVICE=1 test_must_fail git branch all1 main 2>actual &&
 	test_cmp expected actual &&
 	test -z "$(git config branch.all1.merge)"
 '
@@ -1699,7 +1699,7 @@ test_expect_success 'errors if given a bad branch name' '
 	hint: See `man git check-ref-format`
 	hint: Disable this message with "git config advice.refSyntax false"
 	EOF
-	test_must_fail git branch foo..bar >actual 2>&1 &&
+	test_env GIT_ADVICE=1 test_must_fail git branch foo..bar >actual 2>&1 &&
 	test_cmp expect actual
 '
 

t/t3404-rebase-interactive.sh

@@ -2229,7 +2229,7 @@ test_expect_success 'non-merge commands reject merge commits' '
 	EOF
 	(
 		set_replace_editor todo &&
-		test_must_fail git rebase -i HEAD 2>actual
+		test_env GIT_ADVICE=1 test_must_fail git rebase -i HEAD 2>actual
 	) &&
 	cat >expect <<-EOF &&
 	error: ${SQ}pick${SQ} does not accept merge commits

t/t3501-revert-cherry-pick.sh

@@ -181,7 +181,7 @@ test_expect_success 'advice from failed revert' '
 	hint: Disable this message with "git config advice.mergeConflict false"
 	EOF
 	test_commit --append --no-tag "double-add dream" dream dream &&
-	test_must_fail git revert HEAD^ 2>actual &&
+	test_env GIT_ADVICE=1 test_must_fail git revert HEAD^ 2>actual &&
 	test_cmp expected actual
 '