Feat: Convert filepath in Flag to string slice

[dearchap]

What type of PR is this?

(REQUIRED)

• feature

What this PR does / why we need it:

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Which issue(s) this PR fixes:

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Fixes #1166

Special notes for your reviewer:

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Testing

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make test

Release Notes

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[abitrolly]

Should it be named to FilePaths then?

[dearchap]

Thats what I initially was about to do but thought to keep the name same since behavior is same. I can change it. @meatballhat any thoughts ?

[abitrolly]

With many file paths, what will happen if first path does not exist? Will value from the second path overwrite the first?

[meatballhat]

I'm in favor of a rename to FilePaths 👍🏼 and to @abitrolly's point it'd be nice to have clearer documentation around the expected behavior 🙇🏼 (in a later PR!)

[abitrolly]

Not clear how it is supposed to be used. Link to relevant usage examples could help that.

[dearchap]

@abitrolly https://cli.urfave.org/v2/examples/flags/#values-from-files . Previously multiple files would be specified by doing

FilePath: "/path/file1, /path/file2, ....'

So this change makes the file paths more explicit

FilePath: []string{"/path/file1","/path/file2"....}

[abitrolly]

@dearchap should the example be updated then?

            &cli.StringFlag{
                Name:     "password",
                Aliases:  []string{"p"},
                Usage:    "password for the mysql database",
                FilePath: "/etc/mysql/password",
            },

[dearchap]

@abitrolly Yes. Maybe we'll do a separate PR to update the docs since this change is going into v3 ?

[meatballhat]

Oh! You already renamed to FilePaths 🤦🏼 Thank you!