Reproducible crate builds

src/cargo/ops/cargo_package.rs

@@ -5,12 +5,11 @@ use std::io::SeekFrom;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::sync::Arc;
-use std::time::SystemTime;
 
 use flate2::read::GzDecoder;
 use flate2::{Compression, GzBuilder};
 use log::debug;
-use tar::{Archive, Builder, EntryType, Header};
+use tar::{Archive, Builder, EntryType, Header, HeaderMode};
 
 use crate::core::compiler::{BuildConfig, CompileMode, DefaultExecutor, Executor};
 use crate::core::{Feature, Shell, Verbosity, Workspace};
@@ -510,7 +509,7 @@ fn tar(
                 let metadata = file.metadata().chain_err(|| {
                     format!("could not learn metadata for: `{}`", disk_path.display())
                 })?;
-                header.set_metadata(&metadata);
+                header.set_metadata_in_mode(&metadata, HeaderMode::Deterministic);
                 header.set_cksum();
                 ar.append_data(&mut header, &ar_path, &mut file)
                     .chain_err(|| {
@@ -525,12 +524,6 @@ fn tar(
                 };
                 header.set_entry_type(EntryType::file());
                 header.set_mode(0o644);
-                header.set_mtime(
-                    SystemTime::now()
-                        .duration_since(SystemTime::UNIX_EPOCH)
-                        .unwrap()
-                        .as_secs(),
-                );
                 header.set_size(contents.len() as u64);
                 header.set_cksum();
                 ar.append_data(&mut header, &ar_path, contents.as_bytes())

tests/testsuite/package.rs

@@ -6,8 +6,10 @@ use cargo_test_support::registry::{self, Package};
 use cargo_test_support::{
     basic_manifest, cargo_process, git, path2url, paths, project, symlink_supported, t,
 };
+use flate2::read::GzDecoder;
 use std::fs::{self, read_to_string, File};
 use std::path::Path;
+use tar::Archive;
 
 #[cargo_test]
 fn simple() {
@@ -1917,3 +1919,37 @@ src/main.rs
         ))
         .run();
 }
+
+#[cargo_test]
+fn reproducible_output() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [project]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+                exclude = ["*.txt"]
+                license = "MIT"
+                description = "foo"
+            "#,
+        )
+        .file("src/main.rs", r#"fn main() { println!("hello"); }"#)
+        .build();
+
+    p.cargo("package").run();
+    assert!(p.root().join("target/package/foo-0.0.1.crate").is_file());
+
+    let f = File::open(&p.root().join("target/package/foo-0.0.1.crate")).unwrap();
+    let decoder = GzDecoder::new(f);
+    let mut archive = Archive::new(decoder);
+    for ent in archive.entries().unwrap() {
+        let ent = ent.unwrap();
+        let header = ent.header();
+        assert_eq!(header.mode().unwrap(), 0o644);
+        assert_eq!(header.mtime().unwrap(), 0);
+        assert_eq!(header.username().unwrap().unwrap(), "");
+        assert_eq!(header.groupname().unwrap().unwrap(), "");
+    }
+}