flag: prevent BoolWithInverseFlag.String from panicking without a tab#2314
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alliasgher wants to merge 2 commits intourfave:mainfrom
Open
flag: prevent BoolWithInverseFlag.String from panicking without a tab#2314alliasgher wants to merge 2 commits intourfave:mainfrom
alliasgher wants to merge 2 commits intourfave:mainfrom
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When FlagStringer returns a string without a tab character, strings.Index returns -1 and out[-1:] panics with "slice bounds out of range [-1:]". Guard against this by clamping the index to 0 when no tab is found. In that case the entire FlagStringer output is used as the suffix portion of the formatted string, matching the intent of callers who use a custom stringer without the usual tab layout. Fixes urfave#2303 Signed-off-by: alliasgher <alliasgher123@gmail.com>
Splits TestBoolWithInverseFlagStringNoPanicWithNoTabStringer into multi-character and single-character sub-tests so the `-` vs `--` prefix branch added by the panic guard is fully covered. Signed-off-by: alliasgher <alliasgher123@gmail.com>
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Summary
`BoolWithInverseFlag.String()` panics with `slice bounds out of range [-1:]` when the configured `FlagStringer` returns a string that does not contain a tab character.
```go
out := FlagStringer(bif)
i := strings.Index(out, "\t") // -1 when no tab
// ...
out[i:] // panic: slice bounds out of range [-1:]
```
This happens with custom stringers and with the default stringer when the flag doesn't implement `DocGenerationFlag`.
Fix
Clamp the tab index to 0 when no tab is found. The full `FlagStringer` output is then used as the suffix portion of the formatted string, matching the intent of callers using a custom stringer without the usual tab layout.
Fixes #2303
Checklist