other: clean up some build script code (#1218)

Some build script formatting fixes and cleanup of some code. In
particular, I found some of the nightly version handling code to look
pretty gross so I separated out the parts into functions to clean it up
a bit.

1 files changed, 19 insertions, 13 deletions

diff --git a/build.rs b/build.rs
index 0a051b83..b858a57b 100644
--- a/build.rs
+++ b/build.rs
@@ -12,9 +12,7 @@ fn create_dir(dir: &Path) -> io::Result<()> {
     match &res {
         Ok(()) => {}
         Err(err) => {
-            eprintln!(
-            "Failed to create a directory at location {dir:?}, encountered error {err:?}.  Aborting...",
-        );
+            eprintln!("Failed to create a directory at location {dir:?}, encountered error {err:?}.  Aborting...",);
         }
     }
 
@@ -58,6 +56,14 @@ fn btm_generate() -> io::Result<()> {
     Ok(())
 }
 
+fn extract_sha(sha: Option<&str>) -> Option<&str> {
+    sha.and_then(|sha: &str| sha.get(0..8))
+}
+
+fn output_nightly_version(version: &str, git_hash: &str) {
+    println!("cargo:rustc-env=NIGHTLY_VERSION={version}-nightly-{git_hash}");
+}
+
 fn nightly_version() {
     const ENV_KEY: &str = "BTM_BUILD_RELEASE_CALLER";
 
@@ -65,20 +71,20 @@ fn nightly_version() {
         Some(var) if !var.is_empty() && var == "nightly" => {
             let version = env!("CARGO_PKG_VERSION");
 
-            if let Some(git_hash) = option_env!("CIRRUS_CHANGE_IN_REPO")
-                .and_then(|cirrus_sha: &str| cirrus_sha.get(0..8))
-            {
-                println!("cargo:rustc-env=NIGHTLY_VERSION={version}-nightly-{git_hash}");
-            } else if let Some(git_hash) =
-                option_env!("GITHUB_SHA").and_then(|gha_sha: &str| gha_sha.get(0..8))
-            {
-                println!("cargo:rustc-env=NIGHTLY_VERSION={version}-nightly-{git_hash}");
+            if let Some(hash) = extract_sha(option_env!("CIRRUS_CHANGE_IN_REPO")) {
+                // May be set if we're building with Cirrus CI.
+                output_nightly_version(version, hash);
+            } else if let Some(hash) = extract_sha(option_env!("GITHUB_SHA")) {
+                // May be set if we're building with GHA.
+                output_nightly_version(version, hash);
             } else if let Ok(output) = std::process::Command::new("git")
                 .args(["rev-parse", "--short=8", "HEAD"])
                 .output()
             {
-                let git_hash = String::from_utf8(output.stdout).unwrap();
-                println!("cargo:rustc-env=NIGHTLY_VERSION={version}-nightly-{git_hash}");
+                // If we're not building in either, we do the lazy thing and fall back to
+                // manually grabbing info using git as a command.
+                let hash = String::from_utf8(output.stdout).unwrap();
+                output_nightly_version(version, &hash);
             }
         }
         _ => {}