Merge branch 'js/wincred-empty-cred' into maint

MinGW updates.

* js/wincred-empty-cred:
  wincred: handle empty username/password correctly
  t0302: check helper can handle empty credentials

Author: gitster

contrib/credential/wincred/git-credential-wincred.c

@@ -94,6 +94,12 @@ static WCHAR *wusername, *password, *protocol, *host, *path, target[1024];
 static void write_item(const char *what, LPCWSTR wbuf, int wlen)
 {
 	char *buf;
+
+	if (!wbuf || !wlen) {
+		printf("%s=\n", what);
+		return;
+	}
+
 	int len = WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, NULL, 0, NULL,
 	    FALSE);
 	buf = xmalloc(len);
@@ -160,7 +166,7 @@ static int match_part_last(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim)
 static int match_cred(const CREDENTIALW *cred)
 {
 	LPCWSTR target = cred->TargetName;
-	if (wusername && wcscmp(wusername, cred->UserName))
+	if (wusername && wcscmp(wusername, cred->UserName ? cred->UserName : L""))
 		return 0;
 
 	return match_part(&target, L"git", L":") &&
@@ -183,7 +189,7 @@ static void get_credential(void)
 	for (i = 0; i < num_creds; ++i)
 		if (match_cred(creds[i])) {
 			write_item("username", creds[i]->UserName,
-				wcslen(creds[i]->UserName));
+				creds[i]->UserName ? wcslen(creds[i]->UserName) : 0);
 			write_item("password",
 				(LPCWSTR)creds[i]->CredentialBlob,
 				creds[i]->CredentialBlobSize / sizeof(WCHAR));

t/lib-credential.sh

@@ -44,6 +44,7 @@ helper_test_clean() {
 	reject $1 https example.com user2
 	reject $1 http path.tld user
 	reject $1 https timeout.tld user
+	reject $1 https sso.tld
 }
 
 reject() {
@@ -250,6 +251,24 @@ helper_test() {
 		password=pass2
 		EOF
 	'
+
+	test_expect_success "helper ($HELPER) can store empty username" '
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=sso.tld
+		username=
+		password=
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=sso.tld
+		--
+		protocol=https
+		host=sso.tld
+		username=
+		password=
+		EOF
+	'
 }
 
 helper_test_timeout() {