feat(package): add unstable --message-format flag

The behavior is not implemented yet

Author: weihanglo

src/bin/cargo/commands/package.rs

@@ -1,6 +1,8 @@
 use crate::command_prelude::*;
 
-use cargo::ops::{self, PackageOpts};
+use cargo::ops;
+use cargo::ops::PackageMessageFormat;
+use cargo::ops::PackageOpts;
 
 pub fn cli() -> Command {
     subcommand("package")
@@ -30,6 +32,13 @@ pub fn cli() -> Command {
             "exclude-lockfile",
             "Don't include the lock file when packaging",
         ))
+        .arg(
+            opt("message-format", "Output representation (unstable)")
+                .value_name("FMT")
+                // This currently requires and only works with `--list`.
+                .requires("list")
+                .value_parser(PackageMessageFormat::POSSIBLE_VALUES),
+        )
         .arg_silent_suggestion()
         .arg_package_spec_no_all(
             "Package(s) to assemble",
@@ -75,12 +84,21 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
     }
     let specs = args.packages_from_flags()?;
 
+    let fmt = if let Some(fmt) = args._value_of("message-format") {
+        gctx.cli_unstable()
+            .fail_if_stable_opt("--message-format", 11666)?;
+        fmt.parse()?
+    } else {
+        PackageMessageFormat::Human
+    };
+
     ops::package(
         &ws,
         &PackageOpts {
             gctx,
             verify: !args.flag("no-verify"),
             list: args.flag("list"),
+            fmt,
             check_metadata: !args.flag("no-metadata"),
             allow_dirty: args.flag("allow-dirty"),
             include_lockfile: !args.flag("exclude-lockfile"),

src/cargo/ops/cargo_package/mod.rs

@@ -1,4 +1,5 @@
-use std::collections::{BTreeSet, HashMap};
+use std::collections::BTreeSet;
+use std::collections::HashMap;
 use std::fs::{self, File};
 use std::io::prelude::*;
 use std::io::SeekFrom;
@@ -40,10 +41,38 @@ use unicase::Ascii as UncasedAscii;
 mod vcs;
 mod verify;
 
+/// Message format for `cargo package`.
+///
+/// Currently only affect the output of the `--list` flag.
+#[derive(Debug, Clone)]
+pub enum PackageMessageFormat {
+    Human,
+    Json,
+}
+
+impl PackageMessageFormat {
+    pub const POSSIBLE_VALUES: [&str; 2] = ["human", "json"];
+
+    pub const DEFAULT: &str = "human";
+}
+
+impl std::str::FromStr for PackageMessageFormat {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<PackageMessageFormat, anyhow::Error> {
+        match s {
+            "human" => Ok(PackageMessageFormat::Human),
+            "json" => Ok(PackageMessageFormat::Json),
+            f => bail!("unknown message format `{f}`"),
+        }
+    }
+}
+
 #[derive(Clone)]
 pub struct PackageOpts<'gctx> {
     pub gctx: &'gctx GlobalContext,
     pub list: bool,
+    pub fmt: PackageMessageFormat,
     pub check_metadata: bool,
     pub allow_dirty: bool,
     pub include_lockfile: bool,
@@ -236,8 +265,17 @@ fn do_package<'a>(
         let ar_files = prepare_archive(ws, &pkg, &opts)?;
 
         if opts.list {
-            for ar_file in &ar_files {
-                drop_println!(ws.gctx(), "{}", ar_file.rel_str);
+            match opts.fmt {
+                PackageMessageFormat::Human => {
+                    // While this form is called "human",
+                    // it keeps the old file-per-line format for compatibility.
+                    for ar_file in &ar_files {
+                        drop_println!(ws.gctx(), "{}", ar_file.rel_str);
+                    }
+                }
+                PackageMessageFormat::Json => {
+                    let _ = ws.gctx().shell().print_json(&HashMap::<(), ()>::new());
+                }
             }
         } else {
             let tarball = create_package(ws, &pkg, ar_files, local_reg.as_ref())?;

src/cargo/ops/mod.rs

@@ -10,7 +10,10 @@ pub use self::cargo_fetch::{fetch, FetchOptions};
 pub use self::cargo_install::{install, install_list};
 pub use self::cargo_new::{init, new, NewOptions, NewProjectKind, VersionControl};
 pub use self::cargo_output_metadata::{output_metadata, ExportInfo, OutputMetadataOptions};
-pub use self::cargo_package::{check_yanked, package, PackageOpts};
+pub use self::cargo_package::check_yanked;
+pub use self::cargo_package::package;
+pub use self::cargo_package::PackageMessageFormat;
+pub use self::cargo_package::PackageOpts;
 pub use self::cargo_pkgid::pkgid;
 pub use self::cargo_read_manifest::read_package;
 pub use self::cargo_run::run;

src/cargo/ops/registry/publish.rs

@@ -144,6 +144,7 @@ pub fn publish(ws: &Workspace<'_>, opts: &PublishOpts<'_>) -> CargoResult<()> {
             gctx: opts.gctx,
             verify: opts.verify,
             list: false,
+            fmt: ops::PackageMessageFormat::Human,
             check_metadata: true,
             allow_dirty: opts.allow_dirty,
             include_lockfile: true,

tests/testsuite/cargo_package/help/stdout.term.svg

@@ -135,6 +135,7 @@ mod open_namespaces;
 mod owner;
 mod package;
 mod package_features;
+mod package_message_format;
 mod patch;
 mod path;
 mod paths;