Fix long relative path handling on windows

[sandreas]

On windows long relative paths led to an error (see golang/go#21782). Here is a code example that fails (only on windows, on play it works): https://play.golang.org/p/wMS5gti4SD

To reproduce it you may use this on windows 10:

mkdir C:\inetpub\wwwroot\something_4.0\node_modules\babel-preset-es2015\node_modules\babel-plugin-transform-es2015-block-scoping\node_modules\babel-traverse\node_modules\babel-code-frame\node_modules\chalk\node_modules\strip-ansi\node_modules\ansi-regex\
echo "" > C:\inetpub\wwwroot\something_4.0\node_modules\babel-preset-es2015\node_modules\babel-plugin-transform-es2015-block-scoping\node_modules\babel-traverse\node_modules\babel-code-frame\node_modules\chalk\node_modules\strip-ansi\node_modules\ansi-regex\test.txt

And then use the afero.Walk on C:\inetpub\wwwroot\something_4.0\ with a relative path traversal (e.g. . or node_modules).

Other projects solve this problem in a similar way:

• rclone: https://github.com/rclone/rclone/blob/9e2fbe0f1a9314e1330b4adc9d69de137be12ee6/lib/file/unc_windows.go#L16
• restic: https://github.com/restic/restic/blob/74c0607c9222edec3b0c140bb6fee962d6d2e82d/internal/fs/file_windows.go#L12

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[sandreas]

Is there any plan to merge this or give feedback? Otherwise I can close this...

[sandreas]

Closed due to no feedback within > 18 months.