Move /target/godot-gen -> /$crate/src/gen (the former breaks IDE static analysis)

A directory /.generated in the repo root seems to _mostly_ work, but on CLion it needs an extra "Cargo sync" in fresh/cleaned projects.
This creates extra friction that a crate-local `gen` directory doesn't have. Maybe reconsider this once IDEs handle things better.

Author: Bromeon

.github/composite/godot-itest/action.yml

@@ -76,7 +76,7 @@ runs:
     # Note: no longer fails, as we expect header to be forward-compatible; instead issues a warning
     - name: "Copy and compare GDExtension header"
       if: inputs.artifact-name == 'godot-linux'
-      working-directory: target/godot-gen
+      working-directory: godot-ffi/src/gen
       run: |
         mv $RUNNER_DIR/godot_bin/gdextension_interface.h gdextension_interface.h.bak
         git apply ../../godot-bindings/res/tweaks.patch

godot-bindings/res/tweak.patch

@@ -1,7 +1,7 @@
-diff --git b/target/godot-gen/gdextension_interface.h a/target/godot-gen/gdextension_interface.h
+diff --git b/godot-ffi/src/gen/gdextension_interface.h a/godot-ffi/src/gen/gdextension_interface.h
 index 0b7615f..6db266e 100644
---- b/target/godot-gen/gdextension_interface.h
-+++ a/target/godot-gen/gdextension_interface.h
+--- b/godot-ffi/src/gen/gdextension_interface.h
++++ a/godot-ffi/src/gen/gdextension_interface.h
 @@ -139,22 +139,22 @@ typedef enum {
 
  } GDExtensionVariantOperator;

godot-bindings/src/godot_exe.rs

@@ -17,17 +17,11 @@ use std::process::{Command, Output};
 
 // Note: CARGO_BUILD_TARGET_DIR and CARGO_TARGET_DIR are not set.
 // OUT_DIR would be standing to reason, but it's an unspecified path that cannot be referenced by CI.
-const GODOT_VERSION_PATH: &str = concat!(
-    env!("CARGO_MANIFEST_DIR"),
-    "/../target/godot-gen/godot_version.txt"
-);
-const JSON_PATH: &str = concat!(
-    env!("CARGO_MANIFEST_DIR"),
-    "/../target/godot-gen/extension_api.json"
-);
+const GODOT_VERSION_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/src/gen/godot_version.txt");
+const JSON_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/src/gen/extension_api.json");
 const HEADER_PATH: &str = concat!(
     env!("CARGO_MANIFEST_DIR"),
-    "/../target/godot-gen/gdextension_interface.h"
+    "/src/gen/gdextension_interface.h"
 );
 
 pub fn load_gdextension_json(watch: &mut StopWatch) -> String {

godot-core/Cargo.toml

@@ -17,7 +17,6 @@ custom-godot = ["godot-ffi/custom-godot", "godot-codegen/custom-godot"]
 
 [dependencies]
 godot-ffi = { path = "../godot-ffi" }
-once_cell = "1.8"
 
 # See https://docs.rs/glam/latest/glam/index.html#feature-gates
 glam = { version = "0.22", features = ["debug-glam-assert"] }

godot-core/build.rs

@@ -7,10 +7,9 @@
 use std::path::Path;
 
 fn main() {
-    let gen_path = Path::new(concat!(
-        env!("CARGO_MANIFEST_DIR"),
-        "/../target/godot-gen/core"
-    ));
+    // It would be better to generate this in /.generated or /target/godot-gen, however IDEs currently
+    // struggle with static analysis when symbols are outside the crate directory (April 2023).
+    let gen_path = Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/src/gen"));
 
     if gen_path.exists() {
         std::fs::remove_dir_all(gen_path).unwrap_or_else(|e| panic!("failed to delete dir: {e}"));

godot-core/src/lib.rs

@@ -24,7 +24,6 @@ pub mod engine;
 #[allow(unused_imports, dead_code, non_upper_case_globals, non_snake_case, clippy::too_many_arguments, clippy::let_and_return, clippy::new_ret_no_self)]
 #[allow(clippy::upper_case_acronyms)] // TODO remove this line once we transform names
 #[allow(clippy::wrong_self_convention)] // TODO remove once to_string is const
-#[path = "../../target/godot-gen/core/mod.rs"]
 mod gen;
 
 #[doc(hidden)]

godot-ffi/build.rs

@@ -11,10 +11,9 @@ use std::path::Path;
 fn main() {
     let mut watch = godot_bindings::StopWatch::start();
 
-    let gen_path = Path::new(concat!(
-        env!("CARGO_MANIFEST_DIR"),
-        "/../target/godot-gen/ffi"
-    ));
+    // It would be better to generate this in /.generated or /target/godot-gen, however IDEs currently
+    // struggle with static analysis when symbols are outside the crate directory (April 2023).
+    let gen_path = Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/src/gen"));
     let header_rs_path = gen_path.join("gdextension_interface.rs");
 
     godot_bindings::clear_dir(gen_path, &mut watch);

godot-ffi/src/lib.rs

@@ -17,7 +17,6 @@
     deref_nullptr,
     clippy::redundant_static_lifetimes
 )]
-#[path = "../../target/godot-gen/ffi/mod.rs"]
 pub(crate) mod gen;
 
 mod godot_ffi;