fix(publish): Report all unpublishable packages (#15070)

### What does this PR try to resolve?
I didn't extend this to multiple packages restricted to specific
registries.
It seems less likely to be a problem and more complex to gather and
report.

This was inspired by feedback left at #10948

### How should we test and review this PR?

### Additional information

src/cargo/ops/registry/publish.rs

@@ -703,15 +703,18 @@ fn package_list(pkgs: impl IntoIterator<Item = PackageId>, final_sep: &str) -> S
 }
 
 fn validate_registry(pkgs: &[&Package], reg_or_index: Option<&RegistryOrIndex>) -> CargoResult<()> {
-    for pkg in pkgs {
-        if pkg.publish() == &Some(Vec::new()) {
+    let unpublishable = pkgs
+        .iter()
+        .filter(|pkg| pkg.publish() == &Some(Vec::new()))
+        .map(|pkg| format!("`{}`", pkg.name()))
+        .collect::<Vec<_>>();
+    if !unpublishable.is_empty() {
         bail!(
-                    "`{}` cannot be published.\n\
+            "{} cannot be published.\n\
             `package.publish` must be set to `true` or a non-empty list in Cargo.toml to publish.",
-                    pkg.name(),
+            unpublishable.join(", ")
         );
     }
-    }
 
     let reg_name = match reg_or_index {
         Some(RegistryOrIndex::Registry(r)) => Some(r.as_str()),

tests/testsuite/publish.rs

@@ -4049,3 +4049,65 @@ fn one_unpublishable_package() {
 "#]])
         .run();
 }
+
+#[cargo_test]
+fn multiple_unpublishable_package() {
+    let _alt_reg = registry::RegistryBuilder::new()
+        .http_api()
+        .http_index()
+        .alternative()
+        .build();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [workspace]
+            members = ["dep", "main"]
+            "#,
+        )
+        .file(
+            "main/Cargo.toml",
+            r#"
+            [package]
+            name = "main"
+            version = "0.0.1"
+            edition = "2015"
+            authors = []
+            license = "MIT"
+            description = "main"
+            repository = "bar"
+            publish = false
+
+            [dependencies]
+            dep = { path = "../dep", version = "0.1.0" }
+        "#,
+        )
+        .file("main/src/main.rs", "fn main() {}")
+        .file(
+            "dep/Cargo.toml",
+            r#"
+            [package]
+            name = "dep"
+            version = "0.1.0"
+            edition = "2015"
+            authors = []
+            license = "MIT"
+            description = "dep"
+            repository = "bar"
+            publish = false
+        "#,
+        )
+        .file("dep/src/lib.rs", "")
+        .build();
+
+    p.cargo("publish -Zpackage-workspace")
+        .masquerade_as_nightly_cargo(&["package-workspace"])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] `dep`, `main` cannot be published.
+`package.publish` must be set to `true` or a non-empty list in Cargo.toml to publish.
+
+"#]])
+        .run();
+}