Avoid zero-mtime files

src/entry.rs

@@ -610,6 +610,13 @@ impl<'a> EntryFields<'a> {
 
         if self.preserve_mtime {
             if let Ok(mtime) = self.header.mtime() {
+                // For some more information on this see the comments in
+                // `Header::fill_platform_from`, but the general idea is that
+                // we're trying to avoid 0-mtime files coming out of archives
+                // since some tools don't ingest them well. Perhaps one day
+                // when Cargo stops working with 0-mtime archives we can remove
+                // this.
+                let mtime = if mtime == 0 { 1 } else { mtime };
                 let mtime = FileTime::from_unix_time(mtime as i64, 0);
                 filetime::set_file_handle_times(&f, Some(mtime), Some(mtime)).map_err(|e| {
                     TarError::new(&format!("failed to set mtime for `{}`", dst.display()), e)

src/header.rs

@@ -734,7 +734,16 @@ impl Header {
                 self.set_mode(meta.mode() as u32);
             }
             HeaderMode::Deterministic => {
-                self.set_mtime(0);
+                // We could in theory set the mtime to zero here, but not all
+                // tools seem to behave well when ingesting files with a 0
+                // timestamp. For example rust-lang/cargo#9512 shows that lldb
+                // doesn't ingest files with a zero timestamp correctly.
+                //
+                // We just need things to be deterministic here so just pick
+                // something that isn't zero. This time, chosen after careful
+                // deliberation, corresponds to Nov 29, 1973.
+                self.set_mtime(123456789);
+
                 self.set_uid(0);
                 self.set_gid(0);
 

tests/all.rs

@@ -11,7 +11,7 @@ use std::iter::repeat;
 use std::path::{Path, PathBuf};
 
 use filetime::FileTime;
-use tar::{Archive, Builder, EntryType, Header};
+use tar::{Archive, Builder, EntryType, Header, HeaderMode};
 use tempfile::{Builder as TempBuilder, TempDir};
 
 macro_rules! t {
@@ -645,6 +645,27 @@ fn file_times() {
     assert_eq!(atime.nanoseconds(), 0);
 }
 
+#[test]
+fn zero_file_times() {
+    let td = t!(TempBuilder::new().prefix("tar-rs").tempdir());
+
+    let mut ar = Builder::new(Vec::new());
+    ar.mode(HeaderMode::Deterministic);
+    let path = td.path().join("tmpfile");
+    t!(File::create(&path));
+    t!(ar.append_path_with_name(&path, "a"));
+
+    let data = t!(ar.into_inner());
+    let mut ar = Archive::new(&data[..]);
+    assert!(ar.unpack(td.path()).is_ok());
+
+    let meta = fs::metadata(td.path().join("a")).unwrap();
+    let mtime = FileTime::from_last_modification_time(&meta);
+    let atime = FileTime::from_last_access_time(&meta);
+    assert!(mtime.unix_seconds() != 0);
+    assert!(atime.unix_seconds() != 0);
+}
+
 #[test]
 fn backslash_treated_well() {
     // Insert a file into an archive with a backslash