gui, rpc: support upcoming version format

src/disco/gui/fd_gui_printf.c

@@ -1152,8 +1152,8 @@ fd_gui_printf_peer( fd_gui_t *    gui,
     } else {
       jsonp_open_object( gui->http, "gossip" );
 
-        char version[ 32 ];
-        FD_TEST( fd_cstr_printf( version, sizeof( version ), NULL, "%u.%u.%u", gui->gossip.peers[ gossip_idx ].version.major, gui->gossip.peers[ gossip_idx ].version.minor, gui->gossip.peers[ gossip_idx ].version.patch ) );
+        char version[ 64UL ];
+        FD_TEST( fd_gossip_version_cstr( gui->gossip.peers[ gossip_idx ].version.major, gui->gossip.peers[ gossip_idx ].version.minor, gui->gossip.peers[ gossip_idx ].version.patch, version, sizeof( version ) ) );
         jsonp_string( gui->http, "version", version );
         jsonp_null( gui->http, "client_id" ); /* TODO: Frankendancer support */
         jsonp_ulong( gui->http, "feature_set", gui->gossip.peers[ gossip_idx ].version.feature_set );
@@ -1230,8 +1230,8 @@ peers_printf_node( fd_gui_peers_ctx_t *  peers,
 
     jsonp_open_object( peers->http, "gossip" );
 
-      char version[ 32 ];
-      FD_TEST( fd_cstr_printf( version, sizeof( version ), NULL, "%u.%u.%u", peer->contact_info.version.major, peer->contact_info.version.minor, peer->contact_info.version.patch ) );
+      char version[ 64UL ];
+      FD_TEST( fd_gossip_version_cstr( peer->contact_info.version.major, peer->contact_info.version.minor, peer->contact_info.version.patch, version, sizeof( version ) ) );
       jsonp_string( peers->http, "version", version );
       jsonp_ulong( peers->http, "client_id", peer->contact_info.version.client );
       jsonp_ulong( peers->http, "feature_set", peer->contact_info.version.feature_set );

src/discof/rpc/fd_rpc_tile.c

@@ -1151,7 +1151,11 @@ getClusterNodes( fd_rpc_tile_t * ctx,
     }
     fd_http_server_printf( ctx->http, "\"pubkey\":\"%s\",", identity_cstr );
     fd_http_server_printf( ctx->http, "\"shredVersion\":%u,", ele->ci->shred_version );
-    fd_http_server_printf( ctx->http, "\"version\":\"%u.%u.%u\"", ele->ci->version.major, ele->ci->version.minor, ele->ci->version.patch );
+
+    char version[ 64UL ];
+    FD_TEST( fd_gossip_version_cstr( ele->ci->version.major, ele->ci->version.minor, ele->ci->version.patch, version, sizeof( version ) ) );
+    fd_http_server_printf( ctx->http, "\"version\":\"%s\"", version );
+
     if( FD_UNLIKELY( is_last ) ) fd_http_server_printf( ctx->http, "}" );
     else                         fd_http_server_printf( ctx->http, "}," );
   }

src/flamenco/gossip/fd_gossip_message.h

@@ -2,6 +2,7 @@
 #define HEADER_fd_src_flamenco_gossip_fd_gossip_message_h
 
 #include "../../util/fd_util_base.h"
+#include "../../util/cstr/fd_cstr.h"
 #include "fd_gossip_value.h"
 
 #include <stddef.h>
@@ -430,4 +431,43 @@ fd_gossip_pull_request_init( uchar *       payload,
                              ulong **      out_bloom_bits,
                              ulong **      out_bits_set );
 
+/* fd_gossip_version_cstr converts gossip version fields to a null
+   terminated c-string.  Returns 1 on success and 0 on failure (e.g.
+   small out_sz)
+
+   The 16-bit minor field has a special encoding to support semver
+   prerelease notation.
+    - High 2 bits: prerelease channel (0=stable, 1=rc, 2=beta, 3=alpha)
+    - Low 14 bits: actual minor version number
+
+    Patch field semantics:
+        - If prerelease_bits==0 (stable), `patch` is rendered as the
+          normal semver patch component:
+          `<major>.<minor_actual>.<patch>`.
+        - If prerelease_bits!=0 (prerelease), the semver patch component
+          is forced to 0 and `patch` is interpreted as the prerelease
+          sequence number, rendered as:
+          `<major>.<minor_actual>.0-<channel>.<patch>`.
+
+    Note that due to Frankendancer's existing unique versioning hack,
+    future Frankendancer releases will all be stable (i.e.
+    prerelease_bits==0) and based on stable Agave versions.  This is a
+    permissible compromise given Frankendancer is approaching EOL. */
+static inline int
+fd_gossip_version_cstr( ushort major,
+                 ushort minor,
+                 ushort patch,
+                 char * out,
+                 ulong  out_sz ) {
+  ushort prerelease_bits = (minor >> 14U) & 0x3U;
+  ushort minor_actual = minor & 0x3FFFU;
+
+  if( FD_UNLIKELY( prerelease_bits ) ) {
+    const char * names[] = { "", "rc", "beta", "alpha" };
+    return fd_cstr_printf_check( out, out_sz, NULL, "%hu.%hu.0-%s.%hu", major, minor_actual, names[ prerelease_bits ], patch );
+  } else {
+    return fd_cstr_printf_check( out, out_sz, NULL, "%hu.%hu.%hu", major, minor_actual, patch );
+  }
+}
+
 #endif /* HEADER_fd_src_flamenco_gossip_fd_gossip_message_h */