t4126: make sure a directory with SP at the end is usable

As afb31ad (t1010: fix unnoticed failure on Windows, 2021-12-11)
said:

    On Microsoft Windows, a directory name should never end with a period.
    Quoting from Microsoft documentation[1]:

	Do not end a file or directory name with a space or a period.
	Although the underlying file system may support such names, the
	Windows shell and user interface does not.

    [1]: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file

and the condition addressed by this change is exactly that.  If the
platform is unable to properly create these sample patches about a
file that lives in a directory whose name ends with a SP, there is
no point testing how "git apply" behaves there on the filesystem.

Even though the ultimate purpose of "git apply" is to apply a patch
and to update the filesystem entities, this particular test is
mainly about parsing a patch on a funny pathname correctly, and even
on a system that is incapable of checking out the resulting state
correctly on its filesystem, at least the parsing can and should work
fine.  Rewrite the test to work inside the index without touching the
filesystem.

Helped-by: Jeff King <[email protected]>
Helped-by: Eric Sunshine <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: gitster

t/t4126-apply-empty.sh

@@ -66,26 +66,29 @@ test_expect_success 'apply --index create' '
 	git diff --exit-code
 '
 
-test_expect_success 'apply with no-contents and a funny pathname' '
-	mkdir "funny " &&
-	>"funny /empty" &&
-	git add "funny /empty" &&
-	git diff HEAD "funny /" >sample.patch &&
-	git diff -R HEAD "funny /" >elpmas.patch &&
+test_expect_success 'parsing a patch with no-contents and a funny pathname' '
 	git reset --hard &&
-	rm -fr "funny " &&
+	empty_blob=$(test_oid empty_blob) &&
+	echo "$empty_blob" >expect &&
 
-	git apply --stat --check --apply sample.patch &&
-	test_must_be_empty "funny /empty" &&
+	git update-index --add --cacheinfo "100644,$empty_blob,funny /empty" &&
+	git diff --cached HEAD -- "funny /" >sample.patch &&
+	git diff --cached -R HEAD -- "funny /" >elpmas.patch &&
+	git reset &&
 
-	git apply --stat --check --apply elpmas.patch &&
-	test_path_is_missing "funny /empty" &&
+	git apply --cached --stat --check --apply sample.patch &&
+	git rev-parse --verify ":funny /empty" >actual &&
+	test_cmp expect actual &&
 
-	git apply -R --stat --check --apply elpmas.patch &&
-	test_must_be_empty "funny /empty" &&
+	git apply --cached --stat --check --apply elpmas.patch &&
+	test_must_fail git rev-parse --verify ":funny /empty" &&
 
-	git apply -R --stat --check --apply sample.patch &&
-	test_path_is_missing "funny /empty"
+	git apply -R --cached --stat --check --apply elpmas.patch &&
+	git rev-parse --verify ":funny /empty" >actual &&
+	test_cmp expect actual &&
+
+	git apply -R --cached --stat --check --apply sample.patch &&
+	test_must_fail git rev-parse --verify ":funny /empty"
 '
 
 test_done