tests: make GIT_TEST_GETTEXT_POISON a boolean

Change the GIT_TEST_GETTEXT_POISON variable from being "non-empty?" to
being a more standard boolean variable.

Since it needed to be checked in both C code and shellscript (via test
-n) it was one of the remaining shellscript-like variables. Now that
we have "env--helper" we can change that.

There's a couple of tricky edge cases that arise because we're using
git_env_bool() early, and the config-reading "env--helper".

If GIT_TEST_GETTEXT_POISON is set to an invalid value die_bad_number()
will die, but to do so it would usually call gettext(). Let's detect
the special case of GIT_TEST_GETTEXT_POISON and always emit that
message in the C locale, lest we infinitely loop.

As seen in the updated tests in t0017-env-helper.sh there's also a
caveat related to "env--helper" needing to read the config for trace2
purposes.

Since the C_LOCALE_OUTPUT prerequisite is lazy and relies on
"env--helper" we could get invalid results if we failed to read the
config (e.g. because we'd loop on includes) when combined with
e.g. "test_i18ngrep" wanting to check with "env--helper" if
GIT_TEST_GETTEXT_POISON was true or not.

I'm crossing my fingers and hoping that a test similar to the one I
removed in the earlier "config tests: simplify include cycle test"
change in this series won't happen again, and testing for this
explicitly in "env--helper"'s own tests.

This change breaks existing uses of
e.g. GIT_TEST_GETTEXT_POISON=YesPlease, which we've documented in
po/README and other places. As noted in [1] we might want to consider
also accepting "YesPlease" in "env--helper" as a special-case.

But as the lack of uproar over 6cdccfce1e ("i18n: make GETTEXT_POISON
a runtime option", 2018-11-08) demonstrates the audience for this
option is a really narrow set of git developers, who shouldn't have
much trouble modifying their test scripts, so I think it's better to
deal with that minor headache now and make all the relevant GIT_TEST_*
variables boolean in the same way than carry the "YesPlease"
special-case forward.

1. https://public-inbox.org/git/xmqqtvckm3h8.fsf@gitster-ct.c.googlers.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

7 files changed, 30 insertions, 11 deletions

diff --git a/t/README b/t/README
index 9747971..9a131f4 100644
--- a/t/README
+++ b/t/README
@@ -343,8 +343,8 @@ whether this mode is active, and e.g. skip some tests that are hard to
 refactor to deal with it. The "SYMLINKS" prerequisite is currently
 excluded as so much relies on it, but this might change in the future.
 
-GIT_TEST_GETTEXT_POISON=<non-empty?> turns all strings marked for
-translation into gibberish if non-empty (think "test -n"). Used for
+GIT_TEST_GETTEXT_POISON=<boolean> turns all strings marked for
+translation into gibberish if true. Used for
 spotting those tests that need to be marked with a C_LOCALE_OUTPUT
 prerequisite when adding more strings for translation. See "Testing
 marked strings" in po/README for details.
diff --git a/t/t0017-env-helper.sh b/t/t0017-env-helper.sh
index 709bbbd..c1ecf6a 100755
--- a/t/t0017-env-helper.sh
+++ b/t/t0017-env-helper.sh
@@ -80,4 +80,20 @@ test_expect_success 'env--helper --type=ulong' '
 	test_must_be_empty actual.err
 '
 
+test_expect_success 'env--helper reads config thanks to trace2' '
+	mkdir home &&
+	git config -f home/.gitconfig include.path cycle &&
+	git config -f home/cycle include.path .gitconfig &&
+
+	test_must_fail \
+		env HOME="$(pwd)/home" GIT_TEST_GETTEXT_POISON=false \
+		git config -l 2>err &&
+	grep "exceeded maximum include depth" err &&
+
+	test_must_fail \
+		env HOME="$(pwd)/home" GIT_TEST_GETTEXT_POISON=true \
+		git -C cycle env--helper --type=bool --default=0 --exit-code GIT_TEST_GETTEXT_POISON 2>err &&
+	grep "# GETTEXT POISON #" err
+'
+
 test_done
diff --git a/t/t0205-gettext-poison.sh b/t/t0205-gettext-poison.sh
index a06269f..f9fa16a 100755
--- a/t/t0205-gettext-poison.sh
+++ b/t/t0205-gettext-poison.sh
@@ -5,7 +5,7 @@
 
 test_description='Gettext Shell poison'
 
-GIT_TEST_GETTEXT_POISON=YesPlease
+GIT_TEST_GETTEXT_POISON=true
 export GIT_TEST_GETTEXT_POISON
 . ./lib-gettext.sh
 
@@ -31,4 +31,9 @@ test_expect_success 'eval_gettext: our eval_gettext() fallback has poison semant
     test_cmp expect actual
 '
 
+test_expect_success "gettext: invalid GIT_TEST_GETTEXT_POISON value doesn't infinitely loop" "
+	test_must_fail env GIT_TEST_GETTEXT_POISON=xyz git version 2>error &&
+	grep \"fatal: bad numeric config value 'xyz' for 'GIT_TEST_GETTEXT_POISON': invalid unit\" error
+"
+
 test_done
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index 6b388ba..de294c9 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -314,7 +314,7 @@ test_expect_success 'include cycles are detected' '
 	git -C cycle config include.path cycle &&
 	git config -f cycle/cycle include.path config &&
 	test_must_fail \
-		env GIT_TEST_GETTEXT_POISON= \
+		env GIT_TEST_GETTEXT_POISON=false \
 		git -C cycle config --get-all test.value 2>stderr &&
 	grep "exceeded maximum include depth" stderr
 '
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 5990299..b696bae 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -249,7 +249,7 @@ test_expect_success 'checkout to detach HEAD (with advice declined)' '
 test_expect_success 'checkout to detach HEAD' '
 	git config advice.detachedHead true &&
 	git checkout -f renamer && git clean -f &&
-	GIT_TEST_GETTEXT_POISON= git checkout renamer^ 2>messages &&
+	GIT_TEST_GETTEXT_POISON=false git checkout renamer^ 2>messages &&
 	grep "HEAD is now at 7329388" messages &&
 	test_line_count -gt 1 messages &&
 	H=$(git rev-parse --verify HEAD) &&
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 43cf313..75512c3 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1706,7 +1706,7 @@ test_expect_success 'sourcing the completion script clears cached commands' '
 '
 
 test_expect_success 'sourcing the completion script clears cached merge strategies' '
-	GIT_TEST_GETTEXT_POISON= &&
+	GIT_TEST_GETTEXT_POISON=false &&
 	__git_compute_merge_strategies &&
 	verbose test -n "$__git_merge_strategies" &&
 	. "$GIT_BUILD_DIR/contrib/completion/git-completion.bash" &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 4b34646..ed5d69d 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1443,11 +1443,9 @@ then
 	unset GIT_TEST_GETTEXT_POISON_ORIG
 fi
 
-# Can we rely on git's output in the C locale?
-if test -z "$GIT_TEST_GETTEXT_POISON"
-then
-	test_set_prereq C_LOCALE_OUTPUT
-fi
+test_lazy_prereq C_LOCALE_OUTPUT '
+	! git env--helper --type=bool --default=0 --exit-code GIT_TEST_GETTEXT_POISON
+'
 
 if test -z "$GIT_TEST_CHECK_CACHE_TREE"
 then