[PATCH] Unbreak interactive GPG prompt upon signing

[Johannes Schindelin <johannes.schindelin@gmx.de>]

With the recent update in efee955 (gpg-interface: check gpg signature
creation status, 2016-06-17), we ask GPG to send all status updates to
stderr, and then catch the stderr in an strbuf.

But GPG might fail, and send error messages to stderr. And we simply
do not show them to the user.

Even worse: this swallows any interactive prompt for a passphrase. And
detaches stderr from the tty so that the passphrase cannot be read.

So while the first problem could be fixed (by printing the captured
stderr upon error), the second problem cannot be easily fixed, and
presents a major regression.

So let's just revert commit efee9553a4f97b2ecd8f49be19606dd4cf7d9c28.

This fixes https://github.com/git-for-windows/git/issues/871

Cc: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
Published-As: https://github.com/dscho/git/releases/tag/fix-gpg-v1
Fetch-It-Via: git fetch https://github.com/dscho/git fix-gpg-v1

 gpg-interface.c | 8 ++------
 t/t7004-tag.sh  | 9 +--------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/gpg-interface.c b/gpg-interface.c
index 8672eda..3f3a3f7 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -153,11 +153,9 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 	struct child_process gpg = CHILD_PROCESS_INIT;
 	int ret;
 	size_t i, j, bottom;
-	struct strbuf gpg_status = STRBUF_INIT;
 
 	argv_array_pushl(&gpg.args,
 			 gpg_program,
-			 "--status-fd=2",
 			 "-bsau", signing_key,
 			 NULL);
 
@@ -169,12 +167,10 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 	 */
 	sigchain_push(SIGPIPE, SIG_IGN);
 	ret = pipe_command(&gpg, buffer->buf, buffer->len,
-			   signature, 1024, &gpg_status, 0);
+			   signature, 1024, NULL, 0);
 	sigchain_pop(SIGPIPE);
 
-	ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
-	strbuf_release(&gpg_status);
-	if (ret)
+	if (ret || signature->len == bottom)
 		return error(_("gpg failed to sign the data"));
 
 	/* Strip CR from the line endings, in case we are on Windows. */
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 8b0f71a..f9b7d79 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -1202,17 +1202,10 @@ test_expect_success GPG,RFC1991 \
 # try to sign with bad user.signingkey
 git config user.signingkey BobTheMouse
 test_expect_success GPG \
-	'git tag -s fails if gpg is misconfigured (bad key)' \
+	'git tag -s fails if gpg is misconfigured' \
 	'test_must_fail git tag -s -m tail tag-gpg-failure'
 git config --unset user.signingkey
 
-# try to produce invalid signature
-test_expect_success GPG \
-	'git tag -s fails if gpg is misconfigured (bad signature format)' \
-	'test_config gpg.program echo &&
-	 test_must_fail git tag -s -m tail tag-gpg-failure'
-
-
 # try to verify without gpg:
 
 rm -rf gpghome
-- 
2.10.0.windows.1.6.gc4f481a

base-commit: 6ebdac1bab966b720d776aa43ca188fe378b1f4b