spf13--cobra/zsh_completions.md

Generating Zsh Completion For Your cobra.Command

Please refer to Shell Completions for details.

Zsh completions standardization

Cobra 1.1 standardized its zsh completion support to align it with its other shell completions. Although the API was kept backwards-compatible, some small changes in behavior were introduced.

Deprecation summary

See further below for more details on these deprecations.

• cmd.MarkZshCompPositionalArgumentFile(pos, []string{}) is no longer needed. It is therefore deprecated and silently ignored.
• cmd.MarkZshCompPositionalArgumentFile(pos, glob[]) is deprecated and silently ignored.
  • Instead use ValidArgsFunction with ShellCompDirectiveFilterFileExt.
• cmd.MarkZshCompPositionalArgumentWords() is deprecated and silently ignored.
  • Instead use ValidArgsFunction.

Behavioral changes

Noun completion

Old behavior	New behavior
No file completion by default (opposite of bash)	File completion by default; use ValidArgsFunction with ShellCompDirectiveNoFileComp to turn off file completion on a per-argument basis
Completion of flag names without the - prefix having been typed	Flag names are only completed if the user has typed the first -
cmd.MarkZshCompPositionalArgumentFile(pos, []string{}) used to turn on file completion on a per-argument position basis	File completion for all arguments by default; cmd.MarkZshCompPositionalArgumentFile() is deprecated and silently ignored
cmd.MarkZshCompPositionalArgumentFile(pos, glob[]) used to turn on file completion with glob filtering on a per-argument position basis (zsh-specific)	cmd.MarkZshCompPositionalArgumentFile() is deprecated and silently ignored; use ValidArgsFunction with ShellCompDirectiveFilterFileExt for file extension filtering (not full glob filtering)
cmd.MarkZshCompPositionalArgumentWords(pos, words[]) used to provide completion choices on a per-argument position basis (zsh-specific)	cmd.MarkZshCompPositionalArgumentWords() is deprecated and silently ignored; use ValidArgsFunction to achieve the same behavior

Flag-value completion

Old behavior	New behavior
No file completion by default (opposite of bash)	File completion by default; use RegisterFlagCompletionFunc() with ShellCompDirectiveNoFileComp to turn off file completion
cmd.MarkFlagFilename(flag, []string{}) and similar used to turn on file completion	File completion by default; cmd.MarkFlagFilename(flag, []string{}) no longer needed in this context and silently ignored
cmd.MarkFlagFilename(flag, glob[]) used to turn on file completion with glob filtering (syntax of []string{"*.yaml", "*.yml"} incompatible with bash)	Will continue to work, however, support for bash syntax is added and should be used instead so as to work for all shells ([]string{"yaml", "yml"})
cmd.MarkFlagDirname(flag) only completes directories (zsh-specific)	Has been added for all shells
Completion of a flag name does not repeat, unless flag is of type *Array or *Slice (not supported by bash)	Retained for zsh and added to fish
Completion of a flag name does not provide the = form (unlike bash)	Retained for zsh and added to fish

Improvements

• Custom completion support (ValidArgsFunction and RegisterFlagCompletionFunc())
• File completion by default if no other completions found
• Handling of required flags
• File extension filtering no longer mutually exclusive with bash usage
• Completion of directory names within another directory
• Support for = form of flags