tree b203f2cd75675b61bf8fcb2e01632e2119f85202
parent e1c88f9d3d54265eb3c2f4695d9627adcb7164f5
author Zgroza Klimek <zgroza@chromium.org> 1783008626 +0200
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1783065909 -0700

[rust-project] Support space-separated --cfg arguments

When GN exports `rust-project.json` (via `--export-rust-project`), it
attempts to extract `cfg` arguments from a target's `rustflags` to
populate the `cfg` array in the JSON file. This allows language servers
like `rust-analyzer` to correctly resolve conditional compilation blocks
(e.g. `#[gtest]`).

Prior to this commit, GN only successfully extracts these elements if
they are specified using the single-string format (e.g., `rustflags =
[ "--cfg=foo" ]`). If the build configuration provides the flag and the
argument separately (e.g., `rustflags = [ "--cfg", "foo" ]`), GN ignores
the argument entirely. This results in `rust-analyzer` being unable to
resolve `cfg`-gated code in projects using the space-separated format.

Examples of using the space-separated syntax can be found for example in
Chromium in `build/rust/BUILD.gn`.

Change-Id: I2c99c0645f6052c16c98f557b26ef47c6a6a6964
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/23740
Reviewed-by: Andrew Grieve <agrieve@google.com>
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Commit-Queue: Zgroza (Luke) Klimek <zgroza@chromium.org>