feat: add push.default config key

gix/src/config/tree/mod.rs

@@ -51,6 +51,8 @@ pub(crate) mod root {
         pub const PACK: sections::Pack = sections::Pack;
         /// The `protocol` section.
         pub const PROTOCOL: sections::Protocol = sections::Protocol;
+        /// The `push` section.
+        pub const PUSH: sections::Push = sections::Push;
         /// The `remote` section.
         pub const REMOTE: sections::Remote = sections::Remote;
         /// The `safe` section.
@@ -83,6 +85,7 @@ pub(crate) mod root {
                 &Self::MAILMAP,
                 &Self::PACK,
                 &Self::PROTOCOL,
+                &Self::PUSH,
                 &Self::REMOTE,
                 &Self::SAFE,
                 &Self::SSH,
@@ -95,9 +98,9 @@ pub(crate) mod root {
 
 mod sections;
 pub use sections::{
-    branch, checkout, core, credential, extensions, fetch, gitoxide, http, index, protocol, remote, ssh, Author,
+    branch, checkout, core, credential, extensions, fetch, gitoxide, http, index, protocol, push, remote, ssh, Author,
     Branch, Checkout, Clone, Committer, Core, Credential, Extensions, Fetch, Gitoxide, Http, Index, Init, Mailmap,
-    Pack, Protocol, Remote, Safe, Ssh, Url, User,
+    Pack, Protocol, Push, Remote, Safe, Ssh, Url, User,
 };
 #[cfg(feature = "blob-diff")]
 pub use sections::{diff, Diff};

gix/src/config/tree/sections/mod.rs

@@ -86,6 +86,11 @@ pub mod pack;
 pub struct Protocol;
 pub mod protocol;
 
+/// The `push` top-level section.
+#[derive(Copy, Clone, Default)]
+pub struct Push;
+pub mod push;
+
 /// The `remote` top-level section.
 #[derive(Copy, Clone, Default)]
 pub struct Remote;

gix/src/config/tree/sections/push.rs

@@ -0,0 +1,64 @@
+use crate::{
+    config,
+    config::tree::{keys, Key, Push, Section},
+};
+
+impl Push {
+    /// The `push.default` key
+    pub const DEFAULT: Default = Default::new_with_validate("default", &config::Tree::PUSH, validate::Default);
+}
+
+impl Section for Push {
+    fn name(&self) -> &str {
+        "push"
+    }
+
+    fn keys(&self) -> &[&dyn Key] {
+        &[&Self::DEFAULT]
+    }
+}
+
+/// The `remote.<name>.tagOpt` key type.
+pub type Default = keys::Any<validate::Default>;
+
+mod default {
+    use std::borrow::Cow;
+
+    use crate::{
+        bstr::{BStr, ByteSlice},
+        config,
+        config::tree::push::Default,
+        push,
+    };
+
+    impl Default {
+        /// Try to interpret `value` as `push.default`.
+        pub fn try_into_default(
+            &'static self,
+            value: Cow<'_, BStr>,
+        ) -> Result<push::Default, config::key::GenericErrorWithValue> {
+            Ok(match value.as_ref().as_bytes() {
+                b"nothing" => push::Default::Nothing,
+                b"current" => push::Default::Current,
+                b"upstream" | b"tracking" => push::Default::Upstream,
+                b"simple" => push::Default::Simple,
+                b"matching" => push::Default::Matching,
+                _ => return Err(config::key::GenericErrorWithValue::from_value(self, value.into_owned())),
+            })
+        }
+    }
+}
+
+mod validate {
+    pub struct Default;
+    use std::{borrow::Cow, error::Error};
+
+    use crate::{bstr::BStr, config::tree::keys::Validate};
+
+    impl Validate for Default {
+        fn validate(&self, value: &BStr) -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
+            super::Push::DEFAULT.try_into_default(Cow::Borrowed(value))?;
+            Ok(())
+        }
+    }
+}

gix/src/lib.rs

@@ -187,6 +187,8 @@ pub mod tag;
 
 ///
 pub mod progress;
+///
+pub mod push;
 
 ///
 pub mod diff;

gix/src/push.rs

@@ -0,0 +1,21 @@
+/// All possible values of `push.default`.
+#[derive(Default, Copy, Clone, PartialOrd, PartialEq, Ord, Eq, Hash, Debug)]
+pub enum Default {
+    /// Do not push anything unless a refspec is provided explicitly.
+    ///
+    /// This is for safety.
+    Nothing,
+    /// Push the current branch to update a remote branch with the same name.
+    Current,
+    /// Push the current branch to the branch it would fetch from and merge with,
+    /// i.e. what is configured in `branch.<name>.merge`, retrievable with
+    /// the `@{upstream}` refspec.
+    Upstream,
+    /// Push the current branch with the same name to the remote.
+    /// This is the same as [`Current`](Default::Current), but fails if
+    /// `branch.<name>.merge` is set to a branch that is named differently.
+    #[default]
+    Simple,
+    /// Push *all* branches to their similarly named counterpart on the remote.
+    Matching,
+}

gix/tests/config/tree.rs

@@ -145,6 +145,33 @@ mod ssh {
     }
 }
 
+mod push {
+    use crate::config::tree::bcow;
+    use gix::config::tree::Push;
+    use gix::push;
+
+    #[test]
+    fn default() -> crate::Result {
+        for (actual, expected) in [
+            ("nothing", push::Default::Nothing),
+            ("current", push::Default::Current),
+            ("upstream", push::Default::Upstream),
+            ("tracking", push::Default::Upstream),
+            ("simple", push::Default::Simple),
+            ("matching", push::Default::Matching),
+        ] {
+            assert_eq!(Push::DEFAULT.try_into_default(bcow(actual))?, expected);
+        }
+
+        assert_eq!(
+            Push::DEFAULT.try_into_default(bcow("Nothing")).unwrap_err().to_string(),
+            "The key \"push.default=Nothing\" was invalid",
+            "case-sensitive comparisons"
+        );
+        Ok(())
+    }
+}
+
 mod fetch {
 
     #[test]