Split crate into a proc-macro and a regular library crate (#214)

proc-macro crates are loaded by the compiler instead of by the crate
that depends on it. This means it's not possible to use anything else
than exported anything else than exported proc-macros. But in some cases
we want the generated derives to use structs or traits that are provided
by the library. Two examples of this are:
1. An error type that can be used by the `Into` derive ([#173])
2. Or to support trait objects for the `source` of the `Error` derive
([#122])

This change splits the layout of this crate in two. One crate that only
exports proc-macros and is loaded by the compiler. And a second crate
that re-exports all these macros but is also able to export different
things such as structs and traits.

NOTE: This only refactors the code in this repo. No functional changes
happen in this change. These will be done in follow-up PRs.

[#173]: JelteF/derive_more#173
[#122]: JelteF/derive_more#122

Required for #173 #122

Co-authored-by: tyranron <tyranron@gmail.com>

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
           toolchain: stable
           components: clippy
 
-      - run: cargo clippy --all-features -- -D warnings
+      - run: cargo clippy --workspace --all-features -- -D warnings
 
   rustfmt:
     runs-on: ubuntu-latest
@@ -73,7 +73,7 @@ jobs:
       - name: Install minimal dependencies versions
         run: cargo +nightly update -Z minimal-versions
 
-      - run: cargo test --features testing-helpers
+      - run: cargo test --workspace --features testing-helpers
 
   test:
     strategy:
@@ -94,7 +94,7 @@ jobs:
           toolchain: ${{ matrix.toolchain }}
       - run: rustup default ${{ matrix.toolchain }}
 
-      - run: cargo test --features testing-helpers
+      - run: cargo test --workspace --features testing-helpers
 
   test-features:
     name: test features
@@ -129,7 +129,7 @@ jobs:
         with:
           toolchain: nightly
 
-      - run: cargo +nightly doc
+      - run: cargo +nightly doc --workspace
         env:
           RUSTDOCFLAGS: --cfg docsrs
 
@@ -156,17 +156,17 @@ jobs:
 
       - name: Parse release version
         id: release
-        run: echo ::set-output
-                  name=version::${GITHUB_REF#refs/tags/v}
+        run: echo "version=${GITHUB_REF#refs/tags/v}"
+             >> $GITHUB_OUTPUT
       - name: Verify release version matches `derive_more` Cargo manifest
         run: |
           test "${{ steps.release.outputs.version }}" \
             == "$(grep -m1 'version = "' Cargo.toml | cut -d '"' -f2)"
 
       - name: Parse CHANGELOG link
         id: changelog
-        run: echo ::set-output
-                  name=link::${{ github.server_url }}/${{ github.repository }}/blob/v${{ steps.release.outputs.version }}/CHANGELOG.md#$(sed -n '/^## ${{ steps.release.outputs.version }}/{s/^## \([^ ]*\) - \([0-9].*\)/\1---\2/;s/[^0-9a-z-]*//g;p;}' CHANGELOG.md)
+        run: echo "link=${{ github.server_url }}/${{ github.repository }}/blob/v${{ steps.release.outputs.version }}/CHANGELOG.md#$(sed -n '/^## ${{ steps.release.outputs.version }}/{s/^## \([^ ]*\) - \([0-9].*\)/\1---\2/;s/[^0-9a-z-]*//g;p;}' CHANGELOG.md)"
+             >> $GITHUB_OUTPUT
 
       - uses: softprops/action-gh-release@v1
         with:

CONTRIBUTING.md

@@ -26,7 +26,7 @@ If a new behaviour makes sense, that is different from the current behavior, the
 
 ### Documentation
 
-Documentation is contained in the `doc/*.md` files and [README].
+Documentation is contained in the `impl/doc/*.md` files and [README].
 
 Documentation should be up-to-date with any [PR] changes visible for library end-users.
 
@@ -51,7 +51,7 @@ The best strategy for writing a new integration test is to look at existing inte
 
 #### Documentation tests
 
-These are the [code examples][1] in the `doc/*.md` files and [README].
+These are the [code examples][1] in the `impl/doc/*.md` files and [README].
 
 Writing documentation tests is needed for better illustration of the added/altered capabilities for end-users of the crate.
 
@@ -92,7 +92,7 @@ To produce a new release of the `derive_more` crate, perform the following steps
 
 1. Complete the existing [CHANGELOG] or fill up a new one for the new version.
 2. Update [README] installation instructions with the new version.
-3. Run `cargo release patch` (or `minor`/`major`).
+3. Run `cargo release patch --workspace` (or `minor`/`major`).
 4. Wait for the CI pipeline to complete successfully, and the [GitHub release] being created.
 
 

Cargo.toml

@@ -15,27 +15,18 @@ categories = ["development-tools", "development-tools::procedural-macro-helpers"
 
 include = [
     "src/**/*.rs",
-    "doc/**/*.md",
     "Cargo.toml",
     "LICENSE",
     "README.md",
     "CHANGELOG.md",
     "tests/**/*.rs", # debian packaging wants this
 ]
 
-[lib]
-name = "derive_more"
-proc-macro = true
+[workspace]
+members = ["impl"]
 
 [dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-syn = "1.0.81"
-convert_case = { version = "0.6", optional = true }
-unicode-xid = { version = "0.2.2", optional = true }
-
-[build-dependencies]
-rustc_version = { version = "0.4", optional = true }
+derive_more-impl = { version = "=0.99.17", path = "impl" }
 
 [dev-dependencies]
 rustversion = "1.0"
@@ -48,30 +39,29 @@ github = { repository = "JelteF/derive_more", workflow = "CI" }
 rustdoc-args = ["--cfg", "docsrs"]
 
 [features]
-add_assign = []
-add = []
-as_mut = []
-as_ref = []
-constructor = []
-deref = []
-deref_mut = []
-display = ["syn/extra-traits", "unicode-xid"]
-error = ["syn/extra-traits"]
-from = ["syn/extra-traits"]
-from_str = ["convert_case"]
-index = []
-index_mut = []
-into = ["syn/extra-traits"]
-into_iterator = []
-iterator = []
-mul_assign = ["syn/extra-traits"]
-mul = ["syn/extra-traits"]
-not = ["syn/extra-traits"]
-sum = []
-try_into = ["syn/extra-traits"]
-testing-helpers = ["rustc_version"]
-is_variant = ["convert_case"]
-unwrap = ["convert_case", "rustc_version"]
+add_assign = ["derive_more-impl/add_assign"]
+add = ["derive_more-impl/add"]
+as_mut = ["derive_more-impl/as_mut"]
+as_ref = ["derive_more-impl/as_ref"]
+constructor = ["derive_more-impl/constructor"]
+deref = ["derive_more-impl/deref"]
+deref_mut = ["derive_more-impl/deref_mut"]
+display = ["derive_more-impl/display"]
+error = ["derive_more-impl/error"]
+from = ["derive_more-impl/from"]
+from_str = ["derive_more-impl/from_str"]
+index = ["derive_more-impl/index"]
+index_mut = ["derive_more-impl/index_mut"]
+into = ["derive_more-impl/into"]
+into_iterator = ["derive_more-impl/into_iterator"]
+iterator = ["derive_more-impl/iterator"]
+mul_assign = ["derive_more-impl/mul_assign"]
+mul = ["derive_more-impl/mul"]
+not = ["derive_more-impl/not"]
+sum = ["derive_more-impl/sum"]
+try_into = ["derive_more-impl/try_into"]
+is_variant = ["derive_more-impl/is_variant"]
+unwrap = ["derive_more-impl/unwrap"]
 
 default = [
     "add_assign",
@@ -99,6 +89,8 @@ default = [
     "unwrap"
 ]
 
+testing-helpers = ["derive_more-impl/testing-helpers"]
+
 [[test]]
 name = "add_assign"
 path = "tests/add_assign.rs"

ci/test_all_features.sh

@@ -2,5 +2,5 @@
 set -euxo pipefail
 
 for feature in $(tomljson Cargo.toml | jq --raw-output '.features | keys[]' | grep -v 'default\|testing-helpers'); do
-    cargo test --tests --no-default-features --features "$feature,testing-helpers";
+    cargo test -p derive_more --tests --no-default-features --features "$feature,testing-helpers";
 done

impl/Cargo.toml

@@ -0,0 +1,70 @@
+[package]
+name = "derive_more-impl"
+version = "0.99.17" # should be the same as main crate version
+edition = "2021"
+rust-version = "1.56.0"
+description = "Internal implementation of `derive_more` crate"
+authors = ["Jelte Fennema <github-tech@jeltef.nl>"]
+license = "MIT"
+repository = "https://github.com/JelteF/derive_more"
+documentation = "https://docs.rs/derive_more"
+
+# explicitly no keywords or categories so it cannot be found easily
+
+include = [
+    "src/**/*.rs",
+    "doc/**/*.md",
+    "Cargo.toml",
+    "LICENSE",
+]
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0.81"
+convert_case = { version = "0.6", optional = true }
+unicode-xid = { version = "0.2.2", optional = true }
+
+[build-dependencies]
+rustc_version = { version = "0.4", optional = true }
+
+[dev-dependencies]
+derive_more = { path = ".." }
+
+[badges]
+github = { repository = "JelteF/derive_more", workflow = "CI" }
+
+[package.metadata.docs.rs]
+rustdoc-args = ["--cfg", "docsrs"]
+
+[features]
+add_assign = []
+add = []
+as_mut = []
+as_ref = []
+constructor = []
+deref = []
+deref_mut = []
+display = ["syn/extra-traits", "unicode-xid"]
+error = ["syn/extra-traits"]
+from = ["syn/extra-traits"]
+from_str = ["convert_case"]
+index = []
+index_mut = []
+into = ["syn/extra-traits"]
+into_iterator = []
+iterator = []
+mul_assign = ["syn/extra-traits"]
+mul = ["syn/extra-traits"]
+not = ["syn/extra-traits"]
+sum = []
+try_into = ["syn/extra-traits"]
+is_variant = ["convert_case"]
+unwrap = ["convert_case"]
+
+default = []
+
+testing-helpers = ["rustc_version"]

impl/LICENSE

@@ -0,0 +1 @@
+../LICENSE

impl/README.md

@@ -0,0 +1,12 @@
+# `derive_more-impl`
+
+This crate is an implementation detail of the [`derive_more`][crates.io]. If you
+found this crate by accident you're probably looking for one of the following
+pages of [`derive_more`][crates.io]:
+1. [crates.io]
+2. [docs.rs]
+3. [GitHub]
+
+[crates.io]: https://crates.io/crates/derive_more
+[docs.rs]: https://docs.rs/derive_more/latest/derive_more
+[GitHub]: https://github.com/JelteF/derive_more

doc/error.md → impl/doc/error.md

@@ -47,11 +47,11 @@ ignored for one of these methods by using `#[error(not(backtrace))]` or
 ## Example usage
 
 ```rust
-# #![cfg_attr(feature = "nightly", feature(error_generic_member_access, provide_any))]
+# #![cfg_attr(nightly, feature(error_generic_member_access, provide_any))]
 // Nightly requires enabling this features:
 // #![feature(error_generic_member_access, provide_any)]
-# #[cfg(not(feature = "nightly"))] fn main() {}
-# #[cfg(feature = "nightly")] fn main() {
+# #[cfg(not(nightly))] fn main() {}
+# #[cfg(nightly)] fn main() {
 # use std::{any, error::Error as _, backtrace::Backtrace};
 #
 # use derive_more::{Display, Error, From};