IterableDir does not iterate over all contents created after opening (Linux BTRFS) #17095
Description
Zig Version
0.12.0-dev.286+b0d9bb0bb
Steps to Reproduce and Observed Behavior
Caveat: this may not necessarily be a bug if this is acceptable platform-specific behavior, but it may be an opportunity for enhanced documentation if it is acceptable. Related to #17064 as the apparent underlying cause of that issue (this pattern appears within Package.zig: #17064 (comment)).
Given the following Zig code:
const std = @import("std");
pub fn main() !void {
var dir = try std.fs.cwd().openIterableDir("test", .{});
defer dir.close();
try dir.dir.writeFile("1", "1");
try dir.dir.writeFile("2", "2");
var iter = dir.iterate();
while (try iter.next()) |entry| {
std.debug.print("{s}\n", .{entry.name});
}
}Running this code with an initially empty test directory yields the following output on my machine:
1
Subsequent runs, after test has already been populated with both files, yield the following output:
1
2
Output of uname -a:
Linux toolbox 6.4.12-200.fc38.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Aug 23 17:46:49 UTC 2023 x86_64 GNU/Linux
Expected Behavior
The code should always output
1
2
even if those files were not both present when the IterableDir was opened, or a note should be added to IterableDir's documentation mentioning the platform-specific behavior.
In support of the view that this is not a bug (at least in Zig), the following C code reproduces the same behavior of excluding 2 from the output of the first run on an initially empty test directory:
#import <dirent.h>
#import <errno.h>
#import <stdio.h>
int main(void) {
DIR *dir = opendir("test");
if (!dir) {
perror("open test");
return 1;
}
FILE *file;
if (!(file = fopen("test/1", "w"))) {
perror("open 1");
return 1;
}
fwrite("1", 1, 1, file);
fclose(file);
if (!(file = fopen("test/2", "w"))) {
perror("open 2");
return 1;
}
fwrite("2", 1, 1, file);
fclose(file);
errno = 0;
struct dirent *entry;
while ((entry = readdir(dir))) {
printf("%s\n", entry->d_name);
errno = 0;
}
if (errno != 0) {
perror("read test");
return 1;
}
return 0;
}