Add a JSON output mode to cargo package.

src/bin/cargo/commands/package.rs

@@ -1,16 +1,22 @@
 use crate::command_prelude::*;
 
-use cargo::ops::{self, PackageOpts};
+use cargo::ops::{self, ListMode, PackageOpts};
+use clap::builder::PossibleValuesParser;
 
 pub fn cli() -> Command {
     subcommand("package")
         .about("Assemble the local package into a distributable tarball")
         .arg(
-            flag(
+            opt(
                 "list",
                 "Print files included in a package without making one",
             )
-            .short('l'),
+            .short('l')
+            .default_missing_value("basic")
+            .num_args(0..=1)
+            .require_equals(true)
+            .value_name("MODE")
+            .value_parser(PossibleValuesParser::new(["basic", "json"])),
         )
         .arg(flag(
             "no-verify",
@@ -56,7 +62,11 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
         &PackageOpts {
             gctx,
             verify: !args.flag("no-verify"),
-            list: args.flag("list"),
+            list: match args.get_one::<String>("list").map(String::as_str) {
+                Some("json") => ListMode::Json,
+                Some(_) => ListMode::Basic,
+                None => ListMode::Disabled,
+            },
             check_metadata: !args.flag("no-metadata"),
             allow_dirty: args.flag("allow-dirty"),
             to_package: specs,

src/cargo/ops/cargo_package.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeSet, HashMap};
+use std::collections::{BTreeMap, BTreeSet, HashMap};
 use std::fs::{self, File};
 use std::io::prelude::*;
 use std::io::SeekFrom;
@@ -31,7 +31,7 @@ use unicase::Ascii as UncasedAscii;
 #[derive(Clone)]
 pub struct PackageOpts<'gctx> {
     pub gctx: &'gctx GlobalContext,
-    pub list: bool,
+    pub list: ListMode,
     pub check_metadata: bool,
     pub allow_dirty: bool,
     pub verify: bool,
@@ -42,6 +42,25 @@ pub struct PackageOpts<'gctx> {
     pub cli_features: CliFeatures,
 }
 
+/// Possible values for the --list flag.
+#[derive(Clone, Copy)]
+pub enum ListMode {
+    /// Basic mode: just output the paths that would be included in the package file.
+    Basic,
+
+    /// JSON mode: output the paths that would be included and their sources.
+    Json,
+
+    /// Listing disabled; normal package operation.
+    Disabled,
+}
+
+impl ListMode {
+    fn is_disabled(&self) -> bool {
+        matches!(self, &ListMode::Disabled)
+    }
+}
+
 const ORIGINAL_MANIFEST_FILE: &str = "Cargo.toml.orig";
 const VCS_INFO_FILE: &str = ".cargo_vcs_info.json";
 
@@ -55,13 +74,15 @@ struct ArchiveFile {
     contents: FileContents,
 }
 
+#[derive(Serialize)]
 enum FileContents {
     /// Absolute path to the file on disk to add to the archive.
     OnDisk(PathBuf),
     /// Generates a file.
     Generated(GeneratedFile),
 }
 
+#[derive(Serialize)]
 enum GeneratedFile {
     /// Generates `Cargo.toml` by rewriting the original.
     Manifest,
@@ -98,7 +119,7 @@ pub fn package_one(
     pkg: &Package,
     opts: &PackageOpts<'_>,
 ) -> CargoResult<FileLock> {
-    assert!(!opts.list);
+    assert!(opts.list.is_disabled());
 
     let ar_files = prepare_archive(ws, pkg, opts)?;
     let tarball = create_package(ws, pkg, ar_files)?;
@@ -194,25 +215,36 @@ pub fn package(ws: &Workspace<'_>, opts: &PackageOpts<'_>) -> CargoResult<Option
         };
         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.list {
+            ListMode::Basic => {
+                for ar_file in ar_files {
+                    drop_println!(ws.gctx(), "{}", ar_file.rel_str);
+                }
             }
-        } else {
-            let tarball = create_package(ws, pkg, ar_files)?;
-            if opts.verify {
-                run_verify(ws, pkg, &tarball, &opts)
-                    .with_context(|| "failed to verify package tarball")?;
+            ListMode::Json => {
+                let file_list: BTreeMap<PathBuf, FileContents> = ar_files
+                    .into_iter()
+                    .map(|ar_file| (ar_file.rel_path, ar_file.contents))
+                    .collect();
+
+                serde_json::to_writer_pretty(ws.gctx().shell().out(), &file_list)?;
+            }
+            ListMode::Disabled => {
+                let tarball = create_package(ws, pkg, ar_files)?;
+                if opts.verify {
+                    run_verify(ws, pkg, &tarball, &opts)
+                        .with_context(|| "failed to verify package tarball")?;
+                }
+                dsts.push(tarball);
             }
-            dsts.push(tarball);
         }
     }
 
-    if opts.list {
+    if opts.list.is_disabled() {
+        Ok(Some(dsts))
+    } else {
         // We're just listing, so there's no file output
         Ok(None)
-    } else {
-        Ok(Some(dsts))
     }
 }
 

src/cargo/ops/mod.rs

@@ -10,7 +10,7 @@ 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, package_one, PackageOpts};
+pub use self::cargo_package::{check_yanked, package, package_one, ListMode, 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

@@ -27,6 +27,7 @@ use crate::core::PackageIdSpecQuery;
 use crate::core::SourceId;
 use crate::core::Workspace;
 use crate::ops;
+use crate::ops::ListMode;
 use crate::ops::PackageOpts;
 use crate::ops::Packages;
 use crate::sources::source::QueryKind;
@@ -149,7 +150,7 @@ pub fn publish(ws: &Workspace<'_>, opts: &PublishOpts<'_>) -> CargoResult<()> {
         &PackageOpts {
             gctx: opts.gctx,
             verify: opts.verify,
-            list: false,
+            list: ListMode::Disabled,
             check_metadata: true,
             allow_dirty: opts.allow_dirty,
             to_package: Packages::Default,

src/doc/man/cargo-package.md

@@ -82,6 +82,10 @@ There is no guarantee that the source code in the tarball matches the VCS inform
 Print files included in a package without making one.
 {{/option}}
 
+{{#option "`-l=json`" "`--list=json`" }}
+Output the files included in a package in JSON form, without actually building the package.
+{{/option}}
+
 {{#option "`--no-verify`" }}
 Don't verify the contents by building them.
 {{/option}}

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

@@ -76,6 +76,10 @@ OPTIONS
        -l, --list
            Print files included in a package without making one.
 
+       -l=json, --list=json
+           Output the files included in a package in JSON form, without
+           actually building the package.
+
        --no-verify
            Don’t verify the contents by building them.
 

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

@@ -78,6 +78,11 @@ There is no guarantee that the source code in the tarball matches the VCS inform
 <dd class="option-desc">Print files included in a package without making one.</dd>
 
 
+<dt class="option-term" id="option-cargo-package--l=json"><a class="option-anchor" href="#option-cargo-package--l=json"></a><code>-l=json</code></dt>
+<dt class="option-term" id="option-cargo-package---list=json"><a class="option-anchor" href="#option-cargo-package---list=json"></a><code>--list=json</code></dt>
+<dd class="option-desc">Output the files included in a package in JSON form, without actually building the package.</dd>
+
+
 <dt class="option-term" id="option-cargo-package---no-verify"><a class="option-anchor" href="#option-cargo-package---no-verify"></a><code>--no-verify</code></dt>
 <dd class="option-desc">Don’t verify the contents by building them.</dd>
 

src/etc/man/cargo-package.1

@@ -103,6 +103,12 @@ There is no guarantee that the source code in the tarball matches the VCS inform
 Print files included in a package without making one.
 .RE
 .sp
+\fB\-l=json\fR, 
+\fB\-\-list=json\fR
+.RS 4
+Output the files included in a package in JSON form, without actually building the package.
+.RE
+.sp
 \fB\-\-no\-verify\fR
 .RS 4
 Don\[cq]t verify the contents by building them.