Merge #518

518: `build.rs`: Obtain version from macro; simplify r=Urhengulas a=Urhengulas

Fixes #517.

Co-authored-by: Johann Hemmann <johann.hemmann@code.berlin>

.github/workflows/ci.yml

@@ -101,6 +101,8 @@ jobs:
           - stable
           - nightly
     runs-on: ubuntu-latest
+    env:
+      QEMU_RUN_IGNORE_VERSION: 1
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1

Cargo.toml

@@ -26,6 +26,10 @@ bitflags = "1"
 rustc_version = "0.4"
 trybuild = "1.0.42"
 
+[build-dependencies]
+git-version = "0.3"
+semver = "1.0"
+
 [workspace]
 members = [
   ".",
@@ -49,10 +53,7 @@ lto = "fat"
 opt-level = 3
 overflow-checks = false
 
-[build-dependencies]
-semver = "1.0"
-
 [package.metadata.docs.rs]
 features = ["alloc"]
-rustdoc-args = [ "--cfg=docsrs" ]
+rustdoc-args = ["--cfg=docsrs"]
 targets = ["thumbv6m-none-eabi", "thumbv7em-none-eabihf"]

build.rs

@@ -1,56 +1,50 @@
-use semver::Version;
-use std::{env, error::Error, fs, path::Path, path::PathBuf, process::Command};
+use std::{env, error::Error, fs, path::PathBuf};
+
+use git_version::git_version;
 
 fn main() -> Result<(), Box<dyn Error>> {
-    // Put the linker script somewhere the linker can find it
-    let out = &PathBuf::from(env::var("OUT_DIR")?);
-    let mut linker_script = fs::read_to_string("defmt.x.in")?;
-    let hash = Command::new("git")
-        .args(&["rev-parse", "HEAD"])
-        .output()
-        .ok()
-        .and_then(|output| {
-            if output.status.success() {
-                String::from_utf8(output.stdout).ok()
-            } else {
-                None
-            }
-        });
-    let version = if let Some(hash) = hash {
-        hash
-    } else {
-        assert!(
-            !Path::new(".git").exists(),
-            "you need to install the `git` command line tool to use the git version of `defmt`"
-        );
-
-        // no git info -> assume crates.io
-        let semver = Version::parse(&std::env::var("CARGO_PKG_VERSION")?)?;
-        if semver.major == 0 {
+    // `--match v*` matches defmt tags, e.g. `v0.2.3`, but ignores related crates, e.g. `defmt-decoder-v0.2.2`
+    const GIT_DESCRIBE: &str = git_version!(args = ["--long", "--match", "v*"], cargo_prefix = "");
+
+    let version = match semver::Version::parse(GIT_DESCRIBE) {
+        // if parsing fails it is a git version
+        Err(_) => extract_git_hash(GIT_DESCRIBE).to_string(),
+        // if success it is semver
+        Ok(semver) => match semver.major {
             // minor is breaking when major = 0
-            format!("{}.{}", semver.major, semver.minor)
-        } else {
+            0 => format!("{}.{}", semver.major, semver.minor),
             // ignore minor, patch, pre and build
-            semver.major.to_string()
-        }
+            _ => semver.major.to_string(),
+        },
     };
+
+    // Load linker-script and insert version
+    let mut linker_script = fs::read_to_string("defmt.x.in")?;
     linker_script = linker_script.replace("$DEFMT_VERSION", version.trim());
+
+    // Put the linker script somewhere the linker can find it
+    let out = &PathBuf::from(env::var("OUT_DIR")?);
     fs::write(out.join("defmt.x"), linker_script)?;
     println!("cargo:rustc-link-search={}", out.display());
-    let target = env::var("TARGET")?;
 
     // `"atomic-cas": false` in `--print target-spec-json`
     // last updated: rust 1.48.0
-    match &target[..] {
+    if matches!(
+        &*env::var("TARGET")?,
         "avr-gnu-base"
-        | "msp430-none-elf"
-        | "riscv32i-unknown-none-elf"
-        | "riscv32imc-unknown-none-elf"
-        | "thumbv4t-none-eabi"
-        | "thumbv6m-none-eabi" => {
-            println!("cargo:rustc-cfg=no_cas");
-        }
-        _ => {}
+            | "msp430-none-elf"
+            | "riscv32i-unknown-none-elf"
+            | "riscv32imc-unknown-none-elf"
+            | "thumbv4t-none-eabi"
+            | "thumbv6m-none-eabi"
+    ) {
+        println!("cargo:rustc-cfg=no_cas");
     }
+
     Ok(())
 }
+
+/// Extract git hash from a `git describe` statement
+fn extract_git_hash(git_describe: &str) -> &str {
+    git_describe.split("-").nth(2).unwrap()
+}