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fix: from FIXME(#24570) added more info #148156

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68ab2c1
fix: from implementation of debug for file, added more info
WrldEngine Oct 26, 2025
98a7209
chore: change docs url language path
WrldEngine Oct 26, 2025
33fbf38
chore: library/std/src/sys/fs/windows.rs
WrldEngine Oct 27, 2025
5a42b13
hotfix: fix from co-authored changes
WrldEngine Oct 27, 2025
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11 changes: 10 additions & 1 deletion library/std/src/sys/fs/windows.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1022,12 +1022,21 @@ impl FromRawHandle for File {

impl fmt::Debug for File {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// FIXME(#24570): add more info here (e.g., mode)
let mut b = f.debug_struct("File");
b.field("handle", &self.handle.as_raw_handle());
if let Ok(path) = get_path(self) {
b.field("path", &path);
}

if let Ok(file_attr) = self.file_attr() {
b.field("read", &true);
b.field("write", &file_attr.perm().readonly());
Comment on lines +1032 to +1033
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@ChrisDenton ChrisDenton Oct 28, 2025

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This does not look correct to me. If you use File::create to create and open a write-only file this will claim it's readable when it is not. And a file opened only for reads may not have the readonly attribute set on the file itself.

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@WrldEngine WrldEngine Oct 28, 2025

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This does not look correct to me. If you use File::create to create and open a write-only file this will claim it's readable when it is not. And a file opened only for reads may not have the readonly attribute set on the file itself.

I will rewrite it for ACL
I thought that if I added this information, it would also not bad

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@ChrisDenton ChrisDenton Oct 30, 2025

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I think what matters here is how the file was opened rather than permissions specifically. For example, on Linux this program:

fn main() {
    let f = std::fs::File::options()
        .read(false)
        .write(true)
        .create(true)
        .open("foo")
        .unwrap();
    println!("{f:?}",);
}

Produces this result:

File { fd: 3, path: "/playground/foo", read: false, write: true }

So read is false because you can't read from the opened File. But you can reopen the file and read it.

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@WrldEngine WrldEngine Oct 30, 2025

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As i understand, you interested only in permission during using "session" of file descriptor, not permissions given by system (that i think will be also informative). So, if i add ACCESS_MASK (also add windows target binding from NtQueryObject and another impls) and add acl (via winapi GetSecurityInfo or other similar lower cost functions) to File struct as method file_acl (like file_attr) and finally bind to debug, would that be acceptable to you?


// Getting analogue of file mode (unix) using file attributes
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@ChrisDenton ChrisDenton Oct 28, 2025

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File attributes aren't really an analogue of file mode because they don't have much to do with permissions. That would be ACLs. In any case, what we care most about is how the opened file handle can be used, rather than what the on-disk file has set.

E.g. can I write to this file using this particular file handle? Can I read from the file handle? Attributes don't tell you this.

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@WrldEngine WrldEngine Oct 28, 2025 •
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In windows files readable as default, if attrs set to the readonly of course you cannot write to them and use file handler for writing, i don't get the point about examples part, for debugging this infromation useful, than just check you opened the file in write or read mode i think so

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@ChrisDenton ChrisDenton Oct 30, 2025

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If the File was opened with write(false) you cannot write to it whatever the readonly attribute says.

// See https://learn.microsoft.com/windows/win32/fileio/file-attribute-constants
b.field("attrs", &file_attr.attributes);
}

b.finish()
}
}
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