** Ensure that JSON mode is set up if we're visiting /json, to allow
  ** us to customize some following behaviour (error handling and only
  ** process JSON-mode POST data if we're actually in a /json
  ** page). This is normally set up before this routine is called, but
  ** it looks like the ssh_request_loop() approach to dispatching
  ** might bypass that.
  */
  if( g.json.isJsonMode==0 && zPathInfo!=0 ){
    if(0==strncmp("/json",zPathInfo,5)
       && (zPathInfo[5]==0 || zPathInfo[5]=='/')){
      g.json.isJsonMode = 1;
    }else if(g.zCmdName!=0 && 0==strcmp("server",g.zCmdName)){
      /* When running in server "directory" mode, zPathInfo is
      ** prefixed with the repository's name, so in order to determine
      ** whether or not we're really running in json mode we have to
      ** try a bit harder. Problem reported here:
      ** https://fossil-scm.org/forum/forumpost/e4953666d6
      */
      ReCompiled * pReg = 0;
      const char * zErr = re_compile(&pReg, "^/[^/]+/json(/.*)?", 0);
      assert(zErr==0 && "Regex compilation failed?");
      if(zErr==0 &&
         re_match(pReg, (const unsigned char *)zPathInfo, -1)){
        g.json.isJsonMode = 1;
      }
      re_free(pReg);
    }
  }
#endif
  /* If the repository has not been opened already, then find the
  ** repository based on the first element of PATH_INFO and open it.
  */
  if( !g.repositoryOpen ){
    char *zRepo;               /* Candidate repository name */