Provide feature parity for NodePath with Godot

.gitignore

@@ -26,3 +26,6 @@ exp.rs
 
 # Mac specific
 .DS_Store
+
+# Windows specific
+desktop.ini

godot-codegen/src/special_cases/special_cases.rs

@@ -395,6 +395,11 @@ pub fn is_builtin_method_exposed(builtin_ty: &TyName, godot_method_name: &str) -
         | ("StringName", "to_wchar_buffer")
 
         // NodePath
+        | ("NodePath", "is_absolute")
+        | ("NodePath", "is_empty")
+        | ("NodePath", "get_concatenated_names")
+        | ("NodePath", "get_concatenated_subnames")
+        //| ("NodePath", "get_as_property_path")
 
         // Callable
         | ("Callable", "call")

godot-core/src/builtin/collections/array.rs

@@ -495,7 +495,10 @@ impl<T: ArrayElement> Array<T> {
     /// Array elements are copied to the slice, but any reference types (such as `Array`,
     /// `Dictionary` and `Object`) will still refer to the same value. To create a deep copy, use
     /// [`subarray_deep()`][Self::subarray_deep] instead.
+    ///
+    /// _Godot equivalent: `slice`_
     #[doc(alias = "slice")]
+    // TODO(v0.3): change to i32 like NodePath::slice/subpath() and support+test negative indices.
     pub fn subarray_shallow(&self, begin: usize, end: usize, step: Option<isize>) -> Self {
         self.subarray_impl(begin, end, step, false)
     }
@@ -511,7 +514,10 @@ impl<T: ArrayElement> Array<T> {
     /// All nested arrays and dictionaries are duplicated and will not be shared with the original
     /// array. Note that any `Object`-derived elements will still be shallow copied. To create a
     /// shallow copy, use [`subarray_shallow()`][Self::subarray_shallow] instead.
+    ///
+    /// _Godot equivalent: `slice`_
     #[doc(alias = "slice")]
+    // TODO(v0.3): change to i32 like NodePath::slice/subpath() and support+test negative indices.
     pub fn subarray_deep(&self, begin: usize, end: usize, step: Option<isize>) -> Self {
         self.subarray_impl(begin, end, step, true)
     }

godot-core/src/builtin/collections/packed_array.rs

@@ -212,6 +212,7 @@ macro_rules! impl_packed_array {
             ///
             /// To obtain Rust slices, see [`as_slice`][Self::as_slice] and [`as_mut_slice`][Self::as_mut_slice].
             #[doc(alias = "slice")]
+            // TODO(v0.3): change to i32 like NodePath::slice/subpath() and support+test negative indices.
             pub fn subarray(&self, begin: usize, end: usize) -> Self {
                 let len = self.len();
                 let begin = begin.min(len);

godot-core/src/builtin/string/node_path.rs

@@ -41,8 +41,80 @@ impl NodePath {
         Self { opaque }
     }
 
-    pub fn is_empty(&self) -> bool {
-        self.as_inner().is_empty()
+    /// Returns the node name at position `index`.
+    ///
+    /// If you want to get a property name instead, check out [`get_subname()`][Self::get_subname].
+    ///
+    /// # Example
+    /// ```no_run
+    /// # use godot::prelude::*;
+    /// let path = NodePath::from("../RigidBody2D/Sprite2D");
+    /// godot_print!("{}", path.get_name(0)); // ".."
+    /// godot_print!("{}", path.get_name(1)); // "RigidBody2D"
+    /// godot_print!("{}", path.get_name(2)); // "Sprite"
+    /// ```
+    ///
+    /// # Panics
+    /// In Debug mode, if `index` is out of bounds. In Release, a Godot error is generated and the result is unspecified (but safe).
+    pub fn get_name(&self, index: usize) -> StringName {
+        let inner = self.as_inner();
+        let index = index as i64;
+
+        debug_assert!(
+            index < inner.get_name_count(),
+            "NodePath '{self}': name at index {index} is out of bounds"
+        );
+
+        inner.get_name(index)
+    }
+
+    /// Returns the node subname (property) at position `index`.
+    ///
+    /// If you want to get a node name instead, check out [`get_name()`][Self::get_name].
+    ///
+    /// # Example
+    /// ```no_run
+    /// # use godot::prelude::*;
+    /// let path = NodePath::from("Sprite2D:texture:resource_name");
+    /// godot_print!("{}", path.get_subname(0)); // "texture"
+    /// godot_print!("{}", path.get_subname(1)); // "resource_name"
+    /// ```
+    ///
+    /// # Panics
+    /// In Debug mode, if `index` is out of bounds. In Release, a Godot error is generated and the result is unspecified (but safe).
+    pub fn get_subname(&self, index: usize) -> StringName {
+        let inner = self.as_inner();
+        let index = index as i64;
+
+        debug_assert!(
+            index < inner.get_subname_count(),
+            "NodePath '{self}': subname at index {index} is out of bounds"
+        );
+
+        inner.get_subname(index)
+    }
+
+    /// Returns the number of node names in the path. Property subnames are not included.
+    pub fn get_name_count(&self) -> usize {
+        self.as_inner()
+            .get_name_count()
+            .try_into()
+            .expect("Godot name counts are non-negative ints")
+    }
+
+    /// Returns the number of property names ("subnames") in the path. Each subname in the node path is listed after a colon character (`:`).
+    pub fn get_subname_count(&self) -> usize {
+        self.as_inner()
+            .get_subname_count()
+            .try_into()
+            .expect("Godot subname counts are non-negative ints")
+    }
+
+    /// Returns the total number of names + subnames.
+    ///
+    /// This method does not exist in Godot and is provided in Rust for convenience.
+    pub fn get_total_count(&self) -> usize {
+        self.get_name_count() + self.get_subname_count()
     }
 
     /// Returns a 32-bit integer hash value representing the string.
@@ -53,6 +125,40 @@ impl NodePath {
             .expect("Godot hashes are uint32_t")
     }
 
+    /// Returns the range `begin..exclusive_end` as a new `NodePath`.
+    ///
+    /// The absolute value of `begin` and `exclusive_end` will be clamped to [`get_total_count()`][Self::get_total_count].
+    /// So, to express "until the end", you can simply pass a large value for `exclusive_end`, such as `i32::MAX`.
+    ///
+    /// If either `begin` or `exclusive_end` are negative, they will be relative to the end of the `NodePath`.  \
+    /// For example, `path.subpath(0, -2)` is a shorthand for `path.subpath(0, path.get_total_count() - 2)`.
+    ///
+    /// _Godot equivalent: `slice`_
+    ///
+    /// # Compatibility
+    /// The `slice()` behavior for Godot <= 4.3 is unintuitive, see [#100954](https://github.com/godotengine/godot/pull/100954). godot-rust
+    /// automatically changes this to the fixed version for Godot 4.4+, even when used in older versions. So, the behavior is always the same.
+    // i32 used because it can be negative and many Godot APIs use this, see https://github.com/godot-rust/gdext/pull/982/files#r1893732978.
+    #[cfg(since_api = "4.3")]
+    #[doc(alias = "slice")]
+    pub fn subpath(&self, begin: i32, exclusive_end: i32) -> NodePath {
+        // Polyfill for bug https://github.com/godotengine/godot/pull/100954.
+        // TODO(v0.3) make polyfill (everything but last line) conditional if PR is merged in 4.4.
+        let name_count = self.get_name_count() as i32;
+        let subname_count = self.get_subname_count() as i32;
+        let total_count = name_count + subname_count;
+
+        let mut begin = begin.clamp(-total_count, total_count);
+        if begin < 0 {
+            begin += total_count;
+        }
+        if begin > name_count {
+            begin += 1;
+        }
+
+        self.as_inner().slice(begin as i64, exclusive_end as i64)
+    }
+
     crate::meta::declare_arg_method! {
         /// Use as argument for an [`impl AsArg<GString|StringName>`][crate::meta::AsArg] parameter.
         ///

itest/rust/src/builtin_tests/string/gstring_test.rs

@@ -7,7 +7,7 @@
 
 use std::collections::HashSet;
 
-use crate::framework::{expect_panic, itest};
+use crate::framework::{expect_debug_panic_or_release_ok, itest};
 use godot::builtin::{GString, PackedStringArray};
 
 // TODO use tests from godot-rust/gdnative
@@ -98,14 +98,10 @@ fn string_unicode_at() {
     assert_eq!(s.unicode_at(2), 'A');
     assert_eq!(s.unicode_at(3), '💡');
 
-    #[cfg(debug_assertions)]
-    expect_panic("Debug mode: unicode_at() out-of-bounds panics", || {
-        s.unicode_at(4);
-    });
-
     // Release mode: out-of-bounds prints Godot error, but returns 0.
-    #[cfg(not(debug_assertions))]
-    assert_eq!(s.unicode_at(4), '\0');
+    expect_debug_panic_or_release_ok("unicode_at() out-of-bounds panics", || {
+        assert_eq!(s.unicode_at(4), '\0');
+    });
 }
 
 #[itest]

itest/rust/src/builtin_tests/string/node_path_test.rs

@@ -7,7 +7,7 @@
 
 use std::collections::HashSet;
 
-use crate::framework::itest;
+use crate::framework::{expect_debug_panic_or_release_ok, itest};
 use godot::builtin::{GString, NodePath};
 
 #[itest]
@@ -83,3 +83,46 @@ fn node_path_with_null() {
         assert_eq!(left, right);
     }
 }
+
+#[itest]
+#[cfg(since_api = "4.3")]
+fn node_path_subpath() {
+    let path = NodePath::from("path/to/Node:with:props");
+    let parts = path.get_name_count() + path.get_subname_count();
+
+    assert_eq!(path.subpath(0, 1), "path".into());
+    assert_eq!(path.subpath(1, 2), "to".into());
+    assert_eq!(path.subpath(2, 3), "Node".into());
+    assert_eq!(path.subpath(3, 4), ":with".into());
+    assert_eq!(path.subpath(4, 5), ":props".into());
+
+    assert_eq!(path.subpath(1, -1), "to/Node:with".into());
+    assert_eq!(path.subpath(1, parts as i32 - 1), "to/Node:with".into());
+    assert_eq!(path.subpath(0, -2), "path/to/Node".into());
+    assert_eq!(path.subpath(-3, -1), "Node:with".into());
+    assert_eq!(path.subpath(-2, i32::MAX), ":with:props".into());
+    assert_eq!(path.subpath(-1, i32::MAX), ":props".into());
+}
+
+#[itest]
+fn node_path_get_name() {
+    let path = NodePath::from("../RigidBody2D/Sprite2D");
+    assert_eq!(path.get_name(0), "..".into());
+    assert_eq!(path.get_name(1), "RigidBody2D".into());
+    assert_eq!(path.get_name(2), "Sprite2D".into());
+
+    expect_debug_panic_or_release_ok("NodePath::get_name() out of bounds", || {
+        assert_eq!(path.get_name(3), "".into());
+    })
+}
+
+#[itest]
+fn node_path_get_subname() {
+    let path = NodePath::from("Sprite2D:texture:resource_name");
+    assert_eq!(path.get_subname(0), "texture".into());
+    assert_eq!(path.get_subname(1), "resource_name".into());
+
+    expect_debug_panic_or_release_ok("NodePath::get_subname() out of bounds", || {
+        assert_eq!(path.get_subname(2), "".into());
+    })
+}

itest/rust/src/framework/mod.rs

@@ -144,6 +144,14 @@ pub fn expect_panic(context: &str, code: impl FnOnce()) {
     );
 }
 
+pub fn expect_debug_panic_or_release_ok(_context: &str, code: impl FnOnce()) {
+    #[cfg(debug_assertions)]
+    expect_panic(_context, code);
+
+    #[cfg(not(debug_assertions))]
+    code()
+}
+
 /// Synchronously run a thread and return result. Panics are propagated to caller thread.
 #[track_caller]
 pub fn quick_thread<R, F>(f: F) -> R