potential fix for cargo going OOM during 'updating crates.io index'

Fix found here: rust-lang/cargo#10583
This problem seems to exist on aarch64 building for amd64 and vice-versa.

Author: Qqwy

Earthfile

@@ -5,7 +5,7 @@ VERSION --use-cache-command 0.6
 # - DevkitPro + its wii-dev package
 # - Grrlib
 build-env:
-  FROM --platform=linux/amd64 ghcr.io/rust-lang/rust:nightly-slim
+  FROM ghcr.io/rust-lang/rust:nightly-slim
   WORKDIR /
   COPY ./docker/builder/install-devkitpro-pacman.sh /install-devkitpro-pacman.sh
   RUN chmod +x ./install-devkitpro-pacman.sh
@@ -45,17 +45,21 @@ build-env:
   rustup component add rust-src --toolchain nightly
   SAVE IMAGE --cache-from=ghcr.io/qqwy/wii-rust-build-env:latest wii-rust-build-env:latest
 
+build-env-all-platforms:
+  BUILD --platform=linux/arm64 --platform=linux/amd64 +build
+
 # Build the main game Wii ROM
 build:
   # FROM +build-env
-  FROM --platform=linux/amd64 ghcr.io/qqwy/wii-rust-build-env
+  FROM ghcr.io/qqwy/wii-rust-build-env
   COPY ./app/ /app/
   WORKDIR /app/
   RUN --mount=type=cache,target=/usr/local/cargo/registry/index \
   --mount=type=cache,target=/usr/local/cargo/registry/cache \
   --mount=type=cache,target=/usr/local/cargo/git/db \
   cargo +nightly build -Z build-std=core,alloc --target powerpc-unknown-eabi.json
   SAVE ARTIFACT /build/target/powerpc-unknown-eabi/debug/rust-wii.elf AS LOCAL ./bin/boot.elf
+  SAVE ARTIFACT ./Cargo.lock AS LOCAL ./app/Cargo.lock
 
 # Build a Wii ROM that runs the on-target-device integration test suite.
 build-integration-test:
@@ -72,16 +76,18 @@ build-integration-test:
 # Run unit tests of the `app/lib` subcrate using the normal Rust test flow.
 unit-test:
   FROM --platform=linux/amd64 ghcr.io/rust-lang/rust:nightly-slim
-  RUN --mount=type=cache,target=/usr/local/cargo/registry/index \
-  --mount=type=cache,target=/usr/local/cargo/registry/cache \
-  --mount=type=cache,target=/usr/local/cargo/git/db \
-  rustup +nightly component add rust-src
+  RUN apt update && apt install -y git
+  # RUN --mount=type=cache,target=/usr/local/cargo/registry/index \
+  # --mount=type=cache,target=/usr/local/cargo/registry/cache \
+  # --mount=type=cache,target=/usr/local/cargo/git/db \
+  RUN rustup +nightly component add rust-src
   COPY ./app/lib/ /app/lib/
   WORKDIR /app/lib/
-  RUN --mount=type=cache,target=/usr/local/cargo/registry/index \
-  --mount=type=cache,target=/usr/local/cargo/registry/cache \
-  --mount=type=cache,target=/usr/local/cargo/git/db \
-  cargo +nightly test --color=always
+  # RUN --mount=type=cache,target=/usr/local/cargo/registry/index \
+  # --mount=type=cache,target=/usr/local/cargo/registry/cache \
+  # --mount=type=cache,target=/usr/local/cargo/git/db \
+  RUN cargo +nightly test --color=always
+  SAVE ARTIFACT ./Cargo.lock AS LOCAL ./app/lib/Cargo.lock
 
 # BASE IMAGE CONTAINING DOLPHIN
 # -----------------------------
@@ -126,8 +132,8 @@ integration-test-runner:
 
   # Copy ROM into image:
   RUN mkdir /build
-  COPY +build-integration-test/rust-wii.elf /build/boot.elf
-  # COPY ./bin/boot-test.elf /build/boot.elf
+  # COPY +build-integration-test/rust-wii.elf /build/boot.elf
+  COPY ./bin/boot-test.elf /build/boot.elf
 
   # Run rest of the commands as unprivileged user:
   RUN adduser --disabled-password --gecos '' user
@@ -174,3 +180,12 @@ test:
   BUILD +unit-test # Unit test suite
   BUILD +integration-test
   # TODO Clippy?
+
+
+watch:
+  LOCALLY
+  RUN fswatch --one-per-batch --recursive ./app/src ./app/data ./app/Cargo.toml ./app/build.rs ./app/wrapper.h ./app/powerpc-unknown-eabi.json | \
+    while read dir action file; do \
+      echo -e "\e[1;34m The file '$file' appeared in directory '$dir' via '$action', rebuilding and retesting... \e[0m"; \
+      FORCE_COLOR=1 earthly --use-inline-cache +build; \
+    done

app/.cargo/config.toml

@@ -4,4 +4,7 @@ rustflags = ["-C", "default_linker_libraries=y"]
 
 [unstable]
 build-std = ["core", "compiler_builtins", "alloc"]
-build-std-features = ["compiler-builtins-mem"]
+build-std-features = ["compiler-builtins-mem"]
+
+[net]
+git-fetch-with-cli = true