Update hashbrown dependency

.github/workflows/rust.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest"]
-        rust_channel: ["stable", "beta", "nightly", "1.42.0"]
+        rust_channel: ["stable", "beta", "nightly"]
         include:
           - rust_channel: "stable"
             os: "macOS-latest"
@@ -20,15 +20,10 @@ jobs:
     - uses: actions/checkout@v2
       with:
         submodules: true
-    - name: Install rustup
-      run: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile=minimal
     - name: Install rust channel
       run: |
         rustup install ${{matrix.rust_channel}}
         rustup default ${{matrix.rust_channel}}
-    - name: MSRV dependencies
-      if: matrix.rust_channel == '1.42.0'
-      run: cargo update -p indexmap --precise 1.6.2
     - name: Test debug
       run: cargo test --verbose --features all
     - name: Test release
@@ -49,12 +44,32 @@ jobs:
       - run: cargo build --no-default-features --features read_core,wasm
       - run: cargo build --no-default-features --features doc
 
+  msrv-read:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: true
+      - name: Install rust
+        run: rustup update 1.42.0 && rustup default 1.42.0
+      - name: Test
+        run: cargo test --verbose --no-default-features --features read,std
+
+  msrv-all:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: true
+      - name: Install rust
+        run: rustup update 1.56.1 && rustup default 1.56.1
+      - name: Test
+        run: cargo test --verbose --features all
+
   rustfmt:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Install rustup
-        run: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile=minimal
       - name: Install rust
         run: |
           rustup install stable
@@ -68,8 +83,6 @@ jobs:
       - uses: actions/checkout@v2
         with:
           submodules: true
-      - name: Install rustup
-        run: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile=minimal
       - name: Install rust
         run: |
           rustup install stable

Cargo.toml

@@ -18,7 +18,7 @@ flate2 = { version = "1", optional = true }
 indexmap = { version = "1.6", optional = true }
 wasmparser = { version = "0.57", optional = true }
 memchr = { version = "2.4.1", default-features = false }
-hashbrown = { version = "0.11", features = ["ahash"], default-features = false, optional = true }
+hashbrown = { version = "0.12.0", features = ["ahash"], default-features = false, optional = true }
 
 # Internal feature, only used when building as part of libstd, not part of the
 # stable interface of this crate.

README.md

@@ -34,6 +34,14 @@ fn main() -> Result<(), Box<dyn Error>> {
 
 See [`crates/examples`](crates/examples) for more examples.
 
+## Minimum Supported Rust Version (MSRV)
+
+Changes to MSRV are considered breaking changes. We are conservative about changing the MSRV,
+but sometimes are required to due to dependencies. The MSRV is:
+
+  * 1.42.0 for the `read` feature and its dependencies.
+  * 1.56.1 for the `write` feature and its dependencies.
+
 ## License
 
 Licensed under either of

src/lib.rs

@@ -39,7 +39,7 @@
 //!
 //! /// Reads a file and displays the content of the ".boot" section.
 //! fn main() -> Result<(), Box<dyn Error>> {
-//! # #[cfg(feature = "read")] {
+//! # #[cfg(all(feature = "read", feature = "std"))] {
 //!   let bin_data = fs::read("./multiboot2-binary.elf")?;
 //!   let obj_file = object::File::parse(&*bin_data)?;
 //!   if let Some(section) = obj_file.section_by_name(".boot") {