Add "--workspace" to update command

src/bin/cargo/commands/update.rs

@@ -7,6 +7,7 @@ pub fn cli() -> App {
     subcommand("update")
         .about("Update dependencies as recorded in the local lock file")
         .arg(opt("quiet", "No output printed to stdout").short("q"))
+        .arg(opt("workspace", "Only update the workspace packages").short("w"))
         .arg_package_spec_simple("Package to update")
         .arg(opt(
             "aggressive",
@@ -30,6 +31,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         precise: args.value_of("precise"),
         to_update: values(args, "package"),
         dry_run: args.is_present("dry-run"),
+        workspace: args.is_present("workspace"),
         config,
     };
     ops::update_lockfile(&ws, &update_opts)?;

src/cargo/ops/cargo_generate_lockfile.rs

@@ -17,6 +17,7 @@ pub struct UpdateOptions<'a> {
     pub precise: Option<&'a str>,
     pub aggressive: bool,
     pub dry_run: bool,
+    pub workspace: bool,
 }
 
 pub fn generate_lockfile(ws: &Workspace<'_>) -> CargoResult<()> {
@@ -78,8 +79,10 @@ pub fn update_lockfile(ws: &Workspace<'_>, opts: &UpdateOptions<'_>) -> CargoRes
     let mut to_avoid = HashSet::new();
 
     if opts.to_update.is_empty() {
-        to_avoid.extend(previous_resolve.iter());
-        to_avoid.extend(previous_resolve.unused_patches());
+        if !opts.workspace {
+            to_avoid.extend(previous_resolve.iter());
+            to_avoid.extend(previous_resolve.unused_patches());
+        }
     } else {
         let mut sources = Vec::new();
         for name in opts.to_update.iter() {

src/doc/man/cargo-update.md

@@ -44,6 +44,13 @@ the package to. If the package comes from a git repository, this can be a git
 revision (such as a SHA hash or tag).
 {{/option}}
 
+{{#option "`-w`" "`--workspace`" }}
+Attempt to update only packages defined in the workspace. Other packages
+are updated only if they don't already exist in the lockfile. This
+option is useful for updating `Cargo.lock` after you've changed version
+numbers in `Cargo.toml`.
+{{/option}}
+
 {{#option "`--dry-run`" }}
 Displays what would be updated, but doesn't actually write the lockfile.
 {{/option}}

src/doc/man/generated_txt/cargo-update.txt

@@ -35,6 +35,12 @@ OPTIONS
            to set the package to. If the package comes from a git repository,
            this can be a git revision (such as a SHA hash or tag).
 
+       -w, --workspace
+           Attempt to update only packages defined in the workspace. Other
+           packages are updated only if they don't already exist in the
+           lockfile. This option is useful for updating Cargo.lock after you've
+           changed version numbers in Cargo.toml.
+
        --dry-run
            Displays what would be updated, but doesn't actually write the
            lockfile.

src/doc/src/commands/cargo-update.md

@@ -43,6 +43,14 @@ the package to. If the package comes from a git repository, this can be a git
 revision (such as a SHA hash or tag).</dd>
 
 
+<dt class="option-term" id="option-cargo-update--w"><a class="option-anchor" href="#option-cargo-update--w"></a><code>-w</code></dt>
+<dt class="option-term" id="option-cargo-update---workspace"><a class="option-anchor" href="#option-cargo-update---workspace"></a><code>--workspace</code></dt>
+<dd class="option-desc">Attempt to update only packages defined in the workspace. Other packages
+are updated only if they don't already exist in the lockfile. This
+option is useful for updating <code>Cargo.lock</code> after you've changed version
+numbers in <code>Cargo.toml</code>.</dd>
+
+
 <dt class="option-term" id="option-cargo-update---dry-run"><a class="option-anchor" href="#option-cargo-update---dry-run"></a><code>--dry-run</code></dt>
 <dd class="option-desc">Displays what would be updated, but doesn't actually write the lockfile.</dd>
 

src/etc/man/cargo-update.1

@@ -42,6 +42,15 @@ the package to. If the package comes from a git repository, this can be a git
 revision (such as a SHA hash or tag).
 .RE
 .sp
+\fB\-w\fR, 
+\fB\-\-workspace\fR
+.RS 4
+Attempt to update only packages defined in the workspace. Other packages
+are updated only if they don't already exist in the lockfile. This
+option is useful for updating \fBCargo.lock\fR after you've changed version
+numbers in \fBCargo.toml\fR\&.
+.RE
+.sp
 \fB\-\-dry\-run\fR
 .RS 4
 Displays what would be updated, but doesn't actually write the lockfile.

tests/testsuite/update.rs

@@ -649,3 +649,28 @@ fn dry_run_update() {
     let new_lockfile = p.read_lockfile();
     assert_eq!(old_lockfile, new_lockfile)
 }
+
+#[cargo_test]
+fn workspace_only() {
+    let p = project().file("src/main.rs", "fn main() {}").build();
+    p.cargo("generate-lockfile").run();
+    let lock1 = p.read_lockfile();
+
+    p.change_file(
+        "Cargo.toml",
+        r#"
+            [package]
+            name = "foo"
+            authors = []
+            version = "0.0.2"
+        "#,
+    );
+    p.cargo("update --workspace").run();
+    let lock2 = p.read_lockfile();
+
+    assert_ne!(lock1, lock2);
+    assert!(lock1.contains("0.0.1"));
+    assert!(lock2.contains("0.0.2"));
+    assert!(!lock1.contains("0.0.2"));
+    assert!(!lock2.contains("0.0.1"));
+}