inherit Reader/Writer/ErrWriter from parent on subcommand setup#2329
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inherit Reader/Writer/ErrWriter from parent on subcommand setup#2329c-tonneslan wants to merge 1 commit into
c-tonneslan wants to merge 1 commit into
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setupDefaults runs once per command. The first time it runs for a subcommand it would observe a nil Writer and pin it to os.Stdout, which meant a Writer set on the root never reached the subcommand's Action via c.Writer. Same problem for Reader and ErrWriter. Walk to cmd.parent before defaulting: if the parent already has a non-nil Reader/Writer/ErrWriter, inherit it; otherwise fall back to the os.* defaults exactly as before. Root commands (cmd.parent == nil) keep their existing behavior. Fixes urfave#2325. Signed-off-by: Charlie Tonneslan <cst0520@gmail.com>
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Fixes #2325.
`setupDefaults` runs once per command. The first time it runs for a subcommand it would observe a nil `Writer` and pin it to `os.Stdout`, which meant a `Writer` set on the root never reached the subcommand's `Action` via `c.Writer`. Same problem for `Reader` and `ErrWriter`.
```go
root := &cli.Command{
Name: "demo",
Writer: &buf,
Commands: []*cli.Command{{
Name: "sub",
Action: func(_ context.Context, c *cli.Command) error {
fmt.Fprintln(c.Writer, "from sub") // wrote to os.Stdout, not buf
return nil
},
}},
}
```
Walk to `cmd.parent` before defaulting: if the parent already has a non-nil `Reader` / `Writer` / `ErrWriter`, inherit it; otherwise fall back to the `os.*` defaults exactly as before. Root commands (no parent) keep their existing behavior.
Added `TestSubcommandInheritsRootWriters` to lock in the regression for both Writer and ErrWriter.