feat(toml): Add support for setting the default package version (rust…

…-lang#6583)

Allow changing the default package version by setting the `CARGO_SUGGESTED_PKG_VERSION` environment variable.

src/cargo/util/toml/mod.rs

@@ -17,6 +17,7 @@ use cargo_util_schemas::manifest::{RustVersion, StringOrBool};
 use itertools::Itertools;
 use lazycell::LazyCell;
 use pathdiff::diff_paths;
+use semver::Version;
 use toml_edit::ImDocument;
 use url::Url;
 
@@ -566,7 +567,16 @@ fn normalize_package_toml<'a>(
             .clone()
             .map(|value| field_inherit_with(value, "version", || inherit()?.version()))
             .transpose()?
-            .map(manifest::InheritableField::Value),
+            .map(manifest::InheritableField::Value)
+            .or_else(|| {
+                let suggestion = std::env::var("CARGO_SUGGESTED_PKG_VERSION") else {
+                    return None;
+                };
+                let version = Version::parse(&suggestion.unwrap()) else {
+                    return None;
+                };
+                Some(manifest::InheritableField::Value(version.unwrap()))
+            }),
         authors: original_package
             .authors
             .clone()

src/doc/src/reference/manifest.md

@@ -111,8 +111,11 @@ so versions are considered considered [compatible](semver.md) if their left-most
 See the [Resolver] chapter for more information on how Cargo uses versions to
 resolve dependencies.
 
-This field is optional and defaults to `0.0.0`.  The field is required for publishing packages.
+This field is optional. It defaults to the value of the `CARGO_SUGGESTED_PKG_VERSION`
+environment variable. If the variable is not set or the value is invalid,
+it defaults to `0.0.0`. The field is required for publishing packages.
 
+> **MSRV:** Before 1.86, this field defaulted to `0.0.0`
 > **MSRV:** Before 1.75, this field was required
 
 [SemVer]: https://semver.org

tests/testsuite/build.rs

@@ -2890,6 +2890,57 @@ fn staticlib_rlib_and_bin() {
     p.cargo("build -v").run();
 }
 
+#[cargo_test]
+fn suggested_pkg_version() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "ver"
+            "#,
+        )
+        .file(
+            "src/main.rs",
+            r#"
+                static VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+                fn main() {
+                    println!("{}", VERSION);
+                }
+            "#,
+        )
+        .build();
+
+    p.cargo("build -v").run();
+    p.process(&p.bin("ver"))
+        .with_stdout_data(str![[r#"
+0.0.0
+
+"#]])
+        .run();
+
+    p.cargo("build -v")
+        .env("CARGO_SUGGESTED_PKG_VERSION", "X.Y.Z")
+        .run();
+    p.process(&p.bin("ver"))
+        .with_stdout_data(str![[r#"
+0.0.0
+
+"#]])
+        .run();
+
+    p.cargo("build -v")
+        .env("CARGO_SUGGESTED_PKG_VERSION", "1.2.3")
+        .run();
+    p.process(&p.bin("ver"))
+        .with_stdout_data(str![[r#"
+1.2.3
+
+"#]])
+        .run();
+}
+
 #[cargo_test]
 fn opt_out_of_bin() {
     let p = project()