add --no-vcs option to cargo package

If `cargo package` is run for a crate that is not version controlled in
a way that cargo expects, git2 will overreach upwards and grab a
irrelevant .git repo. This change adds `--no-vcs` as an option to
`cargo package` to prevent this.

Author: zachreizner

src/bin/cargo/commands/package.rs

@@ -23,6 +23,10 @@ pub fn cli() -> App {
             "allow-dirty",
             "Allow dirty working directories to be packaged",
         ))
+        .arg(opt(
+            "no-vcs",
+            "Ignore version control for packaging",
+        ))
         .arg_target_triple("Build for the target triple")
         .arg_target_dir()
         .arg_manifest_path()
@@ -39,6 +43,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
             list: args.is_present("list"),
             check_metadata: !args.is_present("no-metadata"),
             allow_dirty: args.is_present("allow-dirty"),
+            use_vcs: !args.is_present("no-vcs"),
             target: args.target(),
             jobs: args.jobs()?,
             registry: None,

src/cargo/ops/cargo_package.rs

@@ -24,6 +24,7 @@ pub struct PackageOpts<'cfg> {
     pub check_metadata: bool,
     pub allow_dirty: bool,
     pub verify: bool,
+    pub use_vcs: bool,
     pub jobs: Option<u32>,
     pub target: Option<String>,
     pub registry: Option<String>,
@@ -55,8 +56,12 @@ pub fn package(ws: &Workspace, opts: &PackageOpts) -> CargoResult<Option<FileLoc
     // Check (git) repository state, getting the current commit hash if not
     // dirty. This will `bail!` if dirty, unless allow_dirty. Produce json
     // info for any sha1 (HEAD revision) returned.
-    let vcs_info = check_repo_state(pkg, &src_files, &config, opts.allow_dirty)?
-        .map(|h| json!({"git":{"sha1": h}}));
+    let vcs_info = if opts.use_vcs {
+        check_repo_state(pkg, &src_files, &config, opts.allow_dirty)?
+            .map(|h| json!({"git":{"sha1": h}}))
+    } else {
+        None
+    };
 
     if opts.list {
         let root = pkg.root();

src/cargo/ops/registry.rs

@@ -80,6 +80,7 @@ pub fn publish(ws: &Workspace, opts: &PublishOpts) -> CargoResult<()> {
             list: false,
             check_metadata: true,
             allow_dirty: opts.allow_dirty,
+            use_vcs: true,
             target: opts.target.clone(),
             jobs: opts.jobs,
             registry: opts.registry.clone(),