From c2fae802ed696ffd57335671892a4a4171f3b87b Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Sun, 22 May 2022 09:04:19 -0500
Subject: [PATCH] check MSRV in CI

It's very easy to use new rust features without realizing it since
the CI and local development workflows may use the latest rust version.
We try to keep some backwards compatibility with rust versions to make
packaging easier for some OS-level package-managers like Void Linux's.
See #1881.

This change adds a new CI check which uses the cargo-msrv crate to
verify an MSRV version recorded in helix-term's Cargo.toml. When
changing MSRV, we can then edit `helix-term/Cargo.toml`'s
`package.metadata.msrv` key.

The MSRV is set at 1.60.0 for the sake of checkmarks on builds but
ideally we want to support 1.57.0. The PR that fixes the MSRV in #2460
should set this MSRV metadata key back to 1.57.0.

Closes #2482.
---
 .github/workflows/build.yml | 49 ++++++++++++++++++++++++++++++++++++-
 helix-term/Cargo.toml       |  1 +
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 69d88f83695f..8cd2d7364f72 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   check:
-    name: Check
+    name: Check Stable
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
@@ -48,6 +48,53 @@ jobs:
         with:
           command: check
 
+  check-msrv:
+    name: Check MSRV
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+
+      - name: Install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+
+      - name: Cache cargo registry
+        uses: actions/cache@v3
+        with:
+          path: ~/.cargo/registry
+          key: ${{ runner.os }}-v2-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-v2-cargo-registry-
+
+      - name: Cache cargo index
+        uses: actions/cache@v3
+        with:
+          path: ~/.cargo/git
+          key: ${{ runner.os }}-v2-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-v2-cargo-index-
+
+      - name: Cache cargo target dir
+        uses: actions/cache@v3
+        with:
+          path: target
+          key: ${{ runner.os }}-v2-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-v2-cargo-build-target-
+
+      - name: Install cargo-msrv
+        uses: actions-rs/cargo@v1
+        with:
+          command: install
+          args: cargo-msrv
+
+      - name: Check MSRV compatibility
+        uses: actions-rs/cargo@v1
+        with:
+          command: msrv
+          args: --verify --path=helix-term
+
   test:
     name: Test Suite
     runs-on: ${{ matrix.os }}
diff --git a/helix-term/Cargo.toml b/helix-term/Cargo.toml
index 706453ae6588..1a74dc61d4b7 100644
--- a/helix-term/Cargo.toml
+++ b/helix-term/Cargo.toml
@@ -10,6 +10,7 @@ repository = "https://github.com/helix-editor/helix"
 homepage = "https://helix-editor.com"
 include = ["src/**/*", "README.md"]
 default-run = "hx"
+metadata.msrv = "1.60.0"
 
 [package.metadata.nix]
 build = true