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package link
import (
"fmt"
"log"
"os"
)
// ensureSymlink ensures l.path is a symlink pointing at l.target.
//
// Idempotency and clobber policy:
// - already points at the target: nothing to do.
// - points elsewhere: the link is removed and recreated.
// - a real file/dir is in the way: it is renamed to "<path>.old" before the
// link is created (matching the Rexfile's rename-existing behavior).
func ensureSymlink(l *Link) error {
log.Printf("processing symlink: %s -> %s", l.path, l.target)
if l.target == "" {
return fmt.Errorf("symlink %s has no target", l.path)
}
info, err := os.Lstat(l.path)
switch {
case err == nil && info.Mode()&os.ModeSymlink != 0:
current, err := os.Readlink(l.path)
if err != nil {
return fmt.Errorf("failed to read symlink %s: %w", l.path, err)
}
if current == l.target {
log.Printf("symlink %s already points at %s", l.path, l.target)
return nil
}
log.Printf("repointing symlink %s from %s to %s", l.path, current, l.target)
if err := os.Remove(l.path); err != nil {
return fmt.Errorf("failed to remove stale symlink %s: %w", l.path, err)
}
case err == nil:
old := l.path + ".old"
log.Printf("%s is a real file/dir, renaming to %s", l.path, old)
if err := os.Rename(l.path, old); err != nil {
return fmt.Errorf("failed to move existing %s aside: %w", l.path, err)
}
case !os.IsNotExist(err):
return fmt.Errorf("failed to stat %s: %w", l.path, err)
}
if err := os.Symlink(l.target, l.path); err != nil {
return fmt.Errorf("failed to create symlink %s -> %s: %w", l.path, l.target, err)
}
log.Printf("created symlink %s -> %s", l.path, l.target)
return nil
}
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