go config_error ai_generated true

flag: -flag needs an argument: -value

ID: go/flag-parse-unexpected-value

Also available as: JSON · Markdown · 中文
88%Fix Rate
84%Confidence
1Evidence
2024-04-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
go1.21 active — — —
go1.22 active — — —
go1.23 active — — —

Root Cause

A boolean flag or a flag expecting a value is followed by another flag without a value separator, causing the next flag to be interpreted as the value.

generic

中文

一个布尔标志或期望值的标志后面跟着另一个标志而没有值分隔符，导致下一个标志被解释为值。

Official Documentation

https://pkg.go.dev/flag#FlagSet.Parse

Workarounds

  1. 95% success Provide the value after a space: -flag value, or use =: -flag=value. Ensure the flag type matches (e.g., int, string). 
    Provide the value after a space: -flag value, or use =: -flag=value. Ensure the flag type matches (e.g., int, string).
  2. 90% success If the flag is meant to be boolean, define it as bool and don't pass a value: flag.Bool("flag", false, "usage") 
    If the flag is meant to be boolean, define it as bool and don't pass a value: flag.Bool("flag", false, "usage")

中文步骤

  1. 在空格后提供值：-flag value，或使用 =：-flag=value。确保标志类型匹配（例如 int、string）。
  2. 如果标志应为布尔型，将其定义为 bool 且不传递值：flag.Bool("flag", false, "usage")

Dead Ends

Common approaches that don't work:

  1. Adding = between flag and value: -flag=value 40% fail

    This works for flags expecting values, but if the flag is defined as bool, it still fails because bool flags don't take values.

  2. Using double dashes --flag value 60% fail

    Go's flag package treats -- as prefix for long flags; it doesn't change the parsing behavior for value requirement.