Merge branch 'bt/gpg-interface'

What is queued here is only the obviously correct and
uncontroversial code clean-up part, which is an earlier 7 patches,
of a larger series.

The remainder that is not queued introduces a few configuration
variables to deal with e-signature backends with different
signature format.

* bt/gpg-interface:
  gpg-interface: find the last gpg signature line
  gpg-interface: extract gpg line matching helper
  gpg-interface: fix const-correctness of "eol" pointer
  gpg-interface: use size_t for signature buffer size
  gpg-interface: modernize function declarations
  gpg-interface: handle bool user.signingkey
  t7004: fix mistaken tag name

gpg-interface.c

@@ -101,22 +101,26 @@ void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 		fputs(output, stderr);
 }
 
-/*
- * Look at GPG signed content (e.g. a signed tag object), whose
- * payload is followed by a detached signature on it.  Return the
- * offset where the embedded detached signature begins, or the end of
- * the data when there is no such signature.
- */
-size_t parse_signature(const char *buf, unsigned long size)
+static int is_gpg_start(const char *line)
+{
+	return starts_with(line, PGP_SIGNATURE) ||
+		starts_with(line, PGP_MESSAGE);
+}
+
+size_t parse_signature(const char *buf, size_t size)
 {
-	char *eol;
 	size_t len = 0;
-	while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
-			!starts_with(buf + len, PGP_MESSAGE)) {
+	size_t match = size;
+	while (len < size) {
+		const char *eol;
+
+		if (is_gpg_start(buf + len))
+			match = len;
+
 		eol = memchr(buf + len, '\n', size - len);
 		len += eol ? eol - (buf + len) + 1 : size - len;
 	}
-	return len;
+	return match;
 }
 
 void set_signing_key(const char *key)
@@ -128,13 +132,19 @@ void set_signing_key(const char *key)
 int git_gpg_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "user.signingkey")) {
+		if (!value)
+			return config_error_nonbool(var);
 		set_signing_key(value);
+		return 0;
 	}
+
 	if (!strcmp(var, "gpg.program")) {
 		if (!value)
 			return config_error_nonbool(var);
 		gpg_program = xstrdup(value);
+		return 0;
 	}
+
 	return 0;
 }
 
@@ -145,12 +155,6 @@ const char *get_signing_key(void)
 	return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 }
 
-/*
- * Create a detached signature for the contents of "buffer" and append
- * it after "signature"; "buffer" and "signature" can be the same
- * strbuf instance, which would cause the detached signature appended
- * at the end.
- */
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 {
 	struct child_process gpg = CHILD_PROCESS_INIT;
@@ -192,11 +196,6 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 	return 0;
 }
 
-/*
- * Run "gpg" to see if the payload matches the detached signature.
- * gpg_output, when set, receives the diagnostic output from GPG.
- * gpg_status, when set, receives the status output from GPG.
- */
 int verify_signed_buffer(const char *payload, size_t payload_size,
 			 const char *signature, size_t signature_size,
 			 struct strbuf *gpg_output, struct strbuf *gpg_status)

gpg-interface.h

@@ -23,16 +23,43 @@ struct signature_check {
 	char *key;
 };
 
-extern void signature_check_clear(struct signature_check *sigc);
-extern size_t parse_signature(const char *buf, unsigned long size);
-extern void parse_gpg_output(struct signature_check *);
-extern int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key);
-extern int verify_signed_buffer(const char *payload, size_t payload_size, const char *signature, size_t signature_size, struct strbuf *gpg_output, struct strbuf *gpg_status);
-extern int git_gpg_config(const char *, const char *, void *);
-extern void set_signing_key(const char *);
-extern const char *get_signing_key(void);
-extern int check_signature(const char *payload, size_t plen,
-	const char *signature, size_t slen, struct signature_check *sigc);
-void print_signature_buffer(const struct signature_check *sigc, unsigned flags);
+void signature_check_clear(struct signature_check *sigc);
+
+/*
+ * Look at GPG signed content (e.g. a signed tag object), whose
+ * payload is followed by a detached signature on it.  Return the
+ * offset where the embedded detached signature begins, or the end of
+ * the data when there is no such signature.
+ */
+size_t parse_signature(const char *buf, size_t size);
+
+void parse_gpg_output(struct signature_check *);
+
+/*
+ * Create a detached signature for the contents of "buffer" and append
+ * it after "signature"; "buffer" and "signature" can be the same
+ * strbuf instance, which would cause the detached signature appended
+ * at the end.
+ */
+int sign_buffer(struct strbuf *buffer, struct strbuf *signature,
+		const char *signing_key);
+
+/*
+ * Run "gpg" to see if the payload matches the detached signature.
+ * gpg_output, when set, receives the diagnostic output from GPG.
+ * gpg_status, when set, receives the status output from GPG.
+ */
+int verify_signed_buffer(const char *payload, size_t payload_size,
+			 const char *signature, size_t signature_size,
+			 struct strbuf *gpg_output, struct strbuf *gpg_status);
+
+int git_gpg_config(const char *, const char *, void *);
+void set_signing_key(const char *);
+const char *get_signing_key(void);
+int check_signature(const char *payload, size_t plen,
+		    const char *signature, size_t slen,
+		    struct signature_check *sigc);
+void print_signature_buffer(const struct signature_check *sigc,
+			    unsigned flags);
 
 #endif

t/t7004-tag.sh

@@ -1056,7 +1056,18 @@ test_expect_success GPG \
 	git tag -s -F sigblanknonlfile blanknonlfile-signed-tag &&
 	get_tag_msg blanknonlfile-signed-tag >actual &&
 	test_cmp expect actual &&
-	git tag -v signed-tag
+	git tag -v blanknonlfile-signed-tag
+'
+
+test_expect_success GPG 'signed tag with embedded PGP message' '
+	cat >msg <<-\EOF &&
+	-----BEGIN PGP MESSAGE-----
+
+	this is not a real PGP message
+	-----END PGP MESSAGE-----
+	EOF
+	git tag -s -F msg confusing-pgp-message &&
+	git tag -v confusing-pgp-message
 '
 
 # messages with commented lines for signed tags: