Stabilize offline mode.

src/bin/cargo/cli.rs

@@ -32,7 +32,6 @@ Available unstable (nightly-only) flags:
     -Z avoid-dev-deps   -- Avoid installing dev-dependencies if possible
     -Z minimal-versions -- Install minimal dependency versions instead of maximum
     -Z no-index-update  -- Do not update the registry, avoids a network request for benchmarking
-    -Z offline          -- Offline mode that does not perform network requests
     -Z unstable-options -- Allow the usage of unstable options such as --registry
     -Z config-profile   -- Read profiles from .cargo/config files
     -Z install-upgrade  -- `cargo install` will upgrade instead of failing
@@ -168,6 +167,7 @@ fn execute_subcommand(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         &args.value_of("color").map(|s| s.to_string()),
         args.is_present("frozen"),
         args.is_present("locked"),
+        args.is_present("offline"),
         arg_target_dir,
         &args
             .values_of_lossy("unstable-features")
@@ -239,6 +239,7 @@ See 'cargo help <command>' for more information on a specific command.\n",
         )
         .arg(opt("frozen", "Require Cargo.lock and cache are up to date").global(true))
         .arg(opt("locked", "Require Cargo.lock is up to date").global(true))
+        .arg(opt("offline", "Run without accessing the network").global(true))
         .arg(
             Arg::with_name("unstable-features")
                 .help("Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details")

src/cargo/core/features.rs

@@ -322,7 +322,6 @@ impl Features {
 pub struct CliUnstable {
     pub print_im_a_teapot: bool,
     pub unstable_options: bool,
-    pub offline: bool,
     pub no_index_update: bool,
     pub avoid_dev_deps: bool,
     pub minimal_versions: bool,
@@ -367,7 +366,6 @@ impl CliUnstable {
         match k {
             "print-im-a-teapot" => self.print_im_a_teapot = parse_bool(v)?,
             "unstable-options" => self.unstable_options = true,
-            "offline" => self.offline = true,
             "no-index-update" => self.no_index_update = true,
             "avoid-dev-deps" => self.avoid_dev_deps = true,
             "minimal-versions" => self.minimal_versions = true,

src/cargo/core/resolver/errors.rs

@@ -299,9 +299,9 @@ pub(super) fn activation_error(
     };
 
     if let Some(config) = config {
-        if config.cli_unstable().offline {
+        if config.offline() {
             msg.push_str(
-                "\nAs a reminder, you're using offline mode (-Z offline) \
+                "\nAs a reminder, you're using offline mode (--offline) \
                  which can sometimes cause surprising resolution failures, \
                  if this error is too confusing you may wish to retry \
                  without the offline flag.",

src/cargo/ops/cargo_generate_lockfile.rs

@@ -36,7 +36,7 @@ pub fn update_lockfile(ws: &Workspace<'_>, opts: &UpdateOptions<'_>) -> CargoRes
         failure::bail!("you can't generate a lockfile for an empty workspace.")
     }
 
-    if opts.config.cli_unstable().offline {
+    if opts.config.offline() {
         failure::bail!("you can't update in the offline mode");
     }
 

src/cargo/ops/lockfile.rs

@@ -47,7 +47,7 @@ pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &Resolve) -> CargoResult<
     }
 
     if !ws.config().lock_update_allowed() {
-        if ws.config().cli_unstable().offline {
+        if ws.config().offline() {
             failure::bail!("can't update in the offline mode");
         }
 

src/cargo/sources/git/source.rs

@@ -158,9 +158,9 @@ impl<'cfg> Source for GitSource<'cfg> {
         let git_path = self.config.assert_package_cache_locked(&git_path);
         let db_path = git_path.join("db").join(&self.ident);
 
-        if self.config.cli_unstable().offline && !db_path.exists() {
+        if self.config.offline() && !db_path.exists() {
             failure::bail!(
-                "can't checkout from '{}': you are in the offline mode (-Z offline)",
+                "can't checkout from '{}': you are in the offline mode (--offline)",
                 self.remote.url()
             );
         }
@@ -172,7 +172,7 @@ impl<'cfg> Source for GitSource<'cfg> {
         let actual_rev = self.remote.rev_for(&db_path, &self.reference);
         let should_update = actual_rev.is_err() || self.source_id.precise().is_none();
 
-        let (db, actual_rev) = if should_update && !self.config.cli_unstable().offline {
+        let (db, actual_rev) = if should_update && !self.config.offline() {
             self.config.shell().status(
                 "Updating",
                 format!("git repository `{}`", self.remote.url()),

src/cargo/sources/registry/index.rs

@@ -363,7 +363,7 @@ impl<'cfg> RegistryIndex<'cfg> {
         yanked_whitelist: &HashSet<PackageId>,
         f: &mut dyn FnMut(Summary),
     ) -> CargoResult<()> {
-        if self.config.cli_unstable().offline
+        if self.config.offline()
             && self.query_inner_with_online(dep, load, yanked_whitelist, f, false)? != 0
         {
             return Ok(());

src/cargo/sources/registry/remote.rs

@@ -182,7 +182,7 @@ impl<'cfg> RegistryData for RemoteRegistry<'cfg> {
     }
 
     fn update_index(&mut self) -> CargoResult<()> {
-        if self.config.cli_unstable().offline {
+        if self.config.offline() {
             if self.repo()?.is_empty()? {
                 // An empty repository is guaranteed to fail, since hitting
                 // this path means we need at least one crate. This is an

src/cargo/util/config.rs

@@ -52,10 +52,15 @@ pub struct Config {
     rustdoc: LazyCell<PathBuf>,
     /// Whether we are printing extra verbose messages
     extra_verbose: bool,
-    /// `frozen` is set if we shouldn't access the network
+    /// `frozen` is the same as `locked`, but additionally will not access the
+    /// network to determine if the lock file is out-of-date.
     frozen: bool,
-    /// `locked` is set if we should not update lock files
+    /// `locked` is set if we should not update lock files. If the lock file
+    /// is missing, or needs to be updated, an error is produced.
     locked: bool,
+    /// `offline` is set if we should never access the network, but otherwise
+    /// continue operating if possible.
+    offline: bool,
     /// A global static IPC control mechanism (used for managing parallel builds)
     jobserver: Option<jobserver::Client>,
     /// Cli flags of the form "-Z something"
@@ -119,6 +124,7 @@ impl Config {
             extra_verbose: false,
             frozen: false,
             locked: false,
+            offline: false,
             jobserver: unsafe {
                 if GLOBAL_JOBSERVER.is_null() {
                     None
@@ -560,6 +566,7 @@ impl Config {
         color: &Option<String>,
         frozen: bool,
         locked: bool,
+        offline: bool,
         target_dir: &Option<PathBuf>,
         unstable_flags: &[String],
     ) -> CargoResult<()> {
@@ -604,6 +611,11 @@ impl Config {
         self.extra_verbose = extra_verbose;
         self.frozen = frozen;
         self.locked = locked;
+        self.offline = offline
+            || self
+                .get::<Option<bool>>("net.offline")
+                .unwrap_or(None)
+                .unwrap_or(false);
         self.target_dir = cli_target_dir;
         self.cli_flags.parse(unstable_flags)?;
 
@@ -619,7 +631,11 @@ impl Config {
     }
 
     pub fn network_allowed(&self) -> bool {
-        !self.frozen() && !self.cli_unstable().offline
+        !self.frozen() && !self.offline()
+    }
+
+    pub fn offline(&self) -> bool {
+        self.offline
     }
 
     pub fn frozen(&self) -> bool {

src/doc/man/cargo-fetch.adoc

@@ -23,6 +23,10 @@ file before fetching the dependencies.
 
 If `--target` is not specified, then all target dependencies are fetched.
 
+See also the link:https://crates.io/crates/cargo-prefetch[cargo-prefetch]
+plugin which adds a command to download popular crates. This may be useful if
+you plan to use Cargo without a network with the `--offline` flag.
+
 == OPTIONS
 
 === Fetch options

src/doc/man/cargo-install.adoc

@@ -100,6 +100,10 @@ include::options-target-triple.adoc[]
 *--debug*::
     Build with the `dev` profile instead the `release` profile.
 
+=== Manifest Options
+
+include::options-locked.adoc[]
+
 === Miscellaneous Options
 
 include::options-jobs.adoc[]

src/doc/man/generated/cargo-bench.html

@@ -341,6 +341,23 @@ <h3 id="cargo_bench_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-build.html

@@ -286,6 +286,23 @@ <h3 id="cargo_build_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-check.html

@@ -277,6 +277,23 @@ <h3 id="cargo_check_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-clean.html

@@ -141,6 +141,23 @@ <h3 id="cargo_clean_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-doc.html

@@ -245,6 +245,23 @@ <h3 id="cargo_doc_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-fetch.html

@@ -26,6 +26,11 @@ <h2 id="cargo_fetch_description">DESCRIPTION</h2>
 <div class="paragraph">
 <p>If <code>--target</code> is not specified, then all target dependencies are fetched.</p>
 </div>
+<div class="paragraph">
+<p>See also the <a href="https://crates.io/crates/cargo-prefetch">cargo-prefetch</a>
+plugin which adds a command to download popular crates. This may be useful if
+you plan to use Cargo without a network with the <code>--offline</code> flag.</p>
+</div>
 </div>
 </div>
 <div class="sect1">
@@ -113,6 +118,23 @@ <h3 id="cargo_fetch_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-fix.html

@@ -348,6 +348,23 @@ <h3 id="cargo_fix_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>

src/doc/man/generated/cargo-generate-lockfile.html

@@ -91,6 +91,23 @@ <h3 id="cargo_generate_lockfile_manifest_options">Manifest Options</h3>
 access.</p>
 </div>
 </dd>
+<dt class="hdlist1"><strong>--offline</strong></dt>
+<dd>
+<p>Prevents Cargo from accessing the network for any reason. Without this
+flag, Cargo will stop with an error if it needs to access the network and
+the network is not available. With this flag, Cargo will attempt to
+proceed without the network if possible.</p>
+<div class="paragraph">
+<p>Beware that this may result in different dependency resolution than online
+mode. Cargo will restrict itself to crates that are downloaded locally, even
+if there might be a newer version as indicated in the local copy of the index.
+See the <a href="commands/cargo-fetch.html">cargo-fetch(1)</a> command to download dependencies before going
+offline.</p>
+</div>
+<div class="paragraph">
+<p>May also be specified with the <code>net.offline</code> <a href="reference/config.html">config value</a>.</p>
+</div>
+</dd>
 </dl>
 </div>
 </div>