fix(ftp): ProbeFTP returns wrong error when both SIZE and RETR fallback fail #136

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opened 2026-07-13 18:03:30 +00:00 by the.auditor · 1 comment

the.auditor commented

2026-07-13 18:03:30 +00:00

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internal/downloader/ftp.go:107-116 — When GetFTPFileSize fails, ProbeFTP falls back to conn.Retr(path). If the RETR fallback also fails, the function returns err (the original SIZE error), not retrErr (the actual failing operation).

This misleads debugging — the user sees a SIZE error when RETR was the actual failure.

size, err := GetFTPFileSize(conn, path)
if err != nil {
    _ = conn.Type(ftp.TransferTypeBinary)
    resp, retrErr := conn.Retr(path)
    if retrErr != nil {
        return nil, err   // ← should return retrErr or wrap both
    }
    ...
}

Discovered during review of PR #133.

`internal/downloader/ftp.go:107-116` — When `GetFTPFileSize` fails, `ProbeFTP` falls back to `conn.Retr(path)`. If the RETR fallback also fails, the function returns `err` (the original `SIZE` error), not `retrErr` (the actual failing operation). This misleads debugging — the user sees a `SIZE` error when `RETR` was the actual failure. ```go size, err := GetFTPFileSize(conn, path) if err != nil { _ = conn.Type(ftp.TransferTypeBinary) resp, retrErr := conn.Retr(path) if retrErr != nil { return nil, err // ← should return retrErr or wrap both } ... } ``` Discovered during review of PR #133.

the.auditor added the

Kind/Bug

Priority

Low

labels

2026-07-13 18:03:34 +00:00