Ruby limit用法及代碼示例

返回由 --backtrace-limit 命令行選項設置的最大回溯長度。默認值是-1，這意味著無限的回溯。如果該值為零或正數，則 Exception#full_message 生成的錯誤回溯將被縮寫，並且多餘的行將被 ... 3 levels... 替換

$ ruby -r net/http -e "p Thread::Backtrace.limit; Net::HTTP.get(URI('http://wrong.address'))"
- 1
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': Failed to open TCP connection to wrong.address:80 (getaddrinfo: Name or service not known) (SocketError)
    from .../lib/ruby/3.1.0/socket.rb:227:in `foreach'
    from .../lib/ruby/3.1.0/socket.rb:632:in `tcp'
    from .../lib/ruby/3.1.0/net/http.rb:998:in `connect'
    from .../lib/ruby/3.1.0/net/http.rb:976:in `do_start'
    from .../lib/ruby/3.1.0/net/http.rb:965:in `start'
    from .../lib/ruby/3.1.0/net/http.rb:627:in `start'
    from .../lib/ruby/3.1.0/net/http.rb:503:in `get_response'
    from .../lib/ruby/3.1.0/net/http.rb:474:in `get'
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': getaddrinfo: Name or service not known (SocketError)
    from .../lib/ruby/3.1.0/socket.rb:227:in `foreach'
    from .../lib/ruby/3.1.0/socket.rb:632:in `tcp'
    from .../lib/ruby/3.1.0/net/http.rb:998:in `connect'
    from .../lib/ruby/3.1.0/net/http.rb:976:in `do_start'
    from .../lib/ruby/3.1.0/net/http.rb:965:in `start'
    from .../lib/ruby/3.1.0/net/http.rb:627:in `start'
    from .../lib/ruby/3.1.0/net/http.rb:503:in `get_response'
    from .../lib/ruby/3.1.0/net/http.rb:474:in `get'
    from -e:1:in `<main>'

$ ruby --backtrace-limit 2 -r net/http -e "p Thread::Backtrace.limit; Net::HTTP.get(URI('http://wrong.address'))"
2
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': Failed to open TCP connection to wrong.address:80 (getaddrinfo: Name or service not known) (SocketError)
    from .../lib/ruby/3.1.0/socket.rb:227:in `foreach'
    from .../lib/ruby/3.1.0/socket.rb:632:in `tcp'
     ... 7 levels...
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': getaddrinfo: Name or service not known (SocketError)
    from .../lib/ruby/3.1.0/socket.rb:227:in `foreach'
    from .../lib/ruby/3.1.0/socket.rb:632:in `tcp'
     ... 7 levels...

$ ruby --backtrace-limit 0 -r net/http -e "p Thread::Backtrace.limit; Net::HTTP.get(URI('http://wrong.address'))"
0
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': Failed to open TCP connection to wrong.address:80 (getaddrinfo: Name or service not known) (SocketError)
     ... 9 levels...
.../lib/ruby/3.1.0/socket.rb:227:in `getaddrinfo': getaddrinfo: Name or service not known (SocketError)
     ... 9 levels...