server_supports_v2(): use a separate function for die_on_error

The server_supports_v2() helper lets a caller find out if the server
supports a feature, and will optionally die if it's not supported. This
makes the return value confusing, as it's only meaningful when the
function is not asked to die.

Coverity flagged a new call like:

  /* check that we support "foo" */
  server_supports_v2("foo", 1);

complaining that we usually checked the return value, but this time we
didn't. But this call is correct, and other ones that did:

  if (server_supports_v2("foo", 1))
          do_something_with_foo();

are "wrong", in the sense that we know the conditional will always be
true (but there's no bug; the code is simply misleading).

Let's split the "die" behavior into its own function which returns void,
and modify each caller to use the correct one.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/connect.c b/connect.c
index 5ea53deda23527ded642449fa9d803cc12e34477..eef752f14b803e4ac770264abe900f250fedb01d 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -66,7 +66,7 @@ static NORETURN void die_initial_contact(int unexpected)
 }
 
 /* Checks if the server supports the capability 'c' */
-int server_supports_v2(const char *c, int die_on_error)
+int server_supports_v2(const char *c)
 {
        int i;
 
@@ -76,11 +76,13 @@ int server_supports_v2(const char *c, int die_on_error)
                    (!*out || *out == '='))
                        return 1;
        }
+       return 0;
+}
 
-       if (die_on_error)
+void ensure_server_supports_v2(const char *c)
+{
+       if (!server_supports_v2(c))
                die(_("server doesn't support '%s'"), c);
-
-       return 0;
 }
 
 int server_feature_v2(const char *c, const char **v)
@@ -477,7 +479,7 @@ static void send_capabilities(int fd_out, struct packet_reader *reader)
 {
        const char *hash_name;
 
-       if (server_supports_v2("agent", 0))
+       if (server_supports_v2("agent"))
                packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 
        if (server_feature_v2("object-format", &hash_name)) {
@@ -504,17 +506,18 @@ struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
                &transport_options->unborn_head_target : NULL;
        *list = NULL;
 
-       if (server_supports_v2("ls-refs", 1))
-               packet_write_fmt(fd_out, "command=ls-refs\n");
+       ensure_server_supports_v2("ls-refs");
+       packet_write_fmt(fd_out, "command=ls-refs\n");
 
        /* Send capabilities */
        send_capabilities(fd_out, reader);
 
-       if (server_options && server_options->nr &&
-           server_supports_v2("server-option", 1))
+       if (server_options && server_options->nr) {
+               ensure_server_supports_v2("server-option");
                for (i = 0; i < server_options->nr; i++)
                        packet_write_fmt(fd_out, "server-option=%s",
                                         server_options->items[i].string);
+       }
 
        packet_delim(fd_out);
        /* When pushing we don't want to request the peeled tags */

diff --git a/connect.h b/connect.h
index c53586e929e8b6f11194d9aeb9934e0fbecd5983..b26f7de7841838e0d6e88bb81169191f579fb56d 100644 (file)
--- a/connect.h
+++ b/connect.h
@@ -20,7 +20,8 @@ enum protocol_version discover_version(struct packet_reader *reader);
 
 int server_supports_hash(const char *desired, int *feature_supported);
 const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp, int *offset);
-int server_supports_v2(const char *c, int die_on_error);
+int server_supports_v2(const char *c);
+void ensure_server_supports_v2(const char *c);
 int server_feature_v2(const char *c, const char **v);
 int server_supports_feature(const char *c, const char *feature,
                            int die_on_error);

diff --git a/fetch-pack.c b/fetch-pack.c
index 998fc2fa1ed4abd32ad0e723115f568768134d3e..04016d1e3250f28ae6cd53a784913f02879769d8 100644 (file)
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1317,15 +1317,15 @@ static void write_fetch_command_and_capabilities(struct strbuf *req_buf,
 {
        const char *hash_name;
 
-       if (server_supports_v2("fetch", 1))
-               packet_buf_write(req_buf, "command=fetch");
-       if (server_supports_v2("agent", 0))
+       ensure_server_supports_v2("fetch");
+       packet_buf_write(req_buf, "command=fetch");
+       if (server_supports_v2("agent"))
                packet_buf_write(req_buf, "agent=%s", git_user_agent_sanitized());
-       if (advertise_sid && server_supports_v2("session-id", 0))
+       if (advertise_sid && server_supports_v2("session-id"))
                packet_buf_write(req_buf, "session-id=%s", trace2_session_id());
-       if (server_options && server_options->nr &&
-           server_supports_v2("server-option", 1)) {
+       if (server_options && server_options->nr) {
                int i;
+               ensure_server_supports_v2("server-option");
                for (i = 0; i < server_options->nr; i++)
                        packet_buf_write(req_buf, "server-option=%s",
                                         server_options->items[i].string);