Re: [PATCH v5] move rust gitcore crate to a different subdirectory

On Fri, Sep 18, 2026 at 01:20:51AM -0700, Junio C Hamano wrote:

It would have been a friendly thing to do to describe what base was
chosen, especially with a few other topics in flight that touch the
build procedure for Rust part of the system recently, here below the
three-dash line.  

It seems that this patch is designed to apply cleanly on top of Git
2.56-rc1, which already has these topics merged, so I do not have to
worry about conflicts with them when queueing this patch, which is
good.

I must admit I hadn't given much thought about where this would be
applied, but it was based off master at the time of refreshing the
patch, which was, indeed, v2.56.0-rc1.

So things in src/ move to either rust/ directory or rust/src/
directory.

Correct. Mostly rs files (except build.rs) move to rust/src/, and the
rest to rust/.

quoted

-$(RUST_LIB): Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
-	$(QUIET_CARGO)cargo build $(CARGO_ARGS)
+$(RUST_LIB): rust/Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
+	$(QUIET_CARGO)cargo build --manifest-path rust/Cargo.toml $(CARGO_ARGS)
...
-RUST_MEMBER_LIBS = $(foreach target,$(RUST_TARGETS),target/$(target)/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME))
-$(RUST_MEMBER_LIBS): target/%/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME): Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
-	$(QUIET_CARGO)cargo build $(CARGO_ARGS) --target $*
+RUST_MEMBER_LIBS = $(foreach target,$(RUST_TARGETS),rust/target/$(target)/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME))
+$(RUST_MEMBER_LIBS): rust/target/%/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME): rust/Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
+	$(QUIET_CARGO)cargo build --manifest-path rust/Cargo.toml $(CARGO_ARGS) --target $*

Is the reason why we now need to sprinkle --manifest-path all over
is because rust/Cargo.toml is a non-standard place for cargo tool?
Not complaining, but am wondering if it is simpler to set and export
CARGO_MANIFEST_DIR from the Makefile.

It's non-standard in the sense that it's not Cargo.toml is $PWD. An
alternative could be to `cd rust` before running cargo commands.

quoted

diff --git a/meson.build b/meson.build
index 0a95d90d21..432e306b21 100644
--- a/meson.build
+++ b/meson.build

@@ -1795,7 +1795,7 @@ libgit_sources += version_def_h
 
 rust_option = get_option('rust')
 if rust_option.allowed()
-  subdir('src')
+  subdir('rust')

Not 'rust/src'?  Just double-checking.

Not rust/src because the rust meson.build was moved to rust/, not
rust/src. It felt like it was in src/ along the .rs files just because
there was no other place for it in the first place.

quoted

@@ -13,7 +13,7 @@ libgit_rs_sources = [
 cargo_command = [
   shell,
   meson.current_source_dir() / 'cargo-meson.sh',
-  meson.project_source_root(),
+  meson.current_source_dir(),
   meson.current_build_dir(),
 ]

What is this change about?

IIRC project_source_root is the git top-level directory, and
current_source_dir is the one containing meson.build. Keeping
project_source_root would put the target directory at the git top-level,
which would be different from what the Makefile does (since it doesn't
pass a --target-dir)

Mike