use const format for version string

Cargo.lock

@@ -76,6 +76,26 @@ dependencies = [
  "os_str_bytes",
 ]
 
+[[package]]
+name = "const_format"
+version = "0.2.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7309d9b4d3d2c0641e018d449232f2e28f1b22933c137f157d3dbc14228b8c0e"
+dependencies = [
+ "const_format_proc_macros",
+]
+
+[[package]]
+name = "const_format_proc_macros"
+version = "0.2.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d897f47bf7270cf70d370f8f98c1abb6d2d4cf60a6845d30e05bfb90c6568650"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
 [[package]]
 name = "errno"
 version = "0.2.8"
@@ -192,6 +212,7 @@ dependencies = [
  "alpm",
  "anyhow",
  "clap",
+ "const_format",
  "pacdef_macros",
  "path-absolutize",
  "regex",
@@ -372,6 +393,12 @@ version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "84a22b9f218b40614adcb3f4ff08b703773ad44fa9423e4e0d346d5db86e4ebc"
 
+[[package]]
+name = "unicode-xid"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f962df74c8c05a667b5ee8bcf162993134c104e96440b663c8daa176dc772d8c"
+
 [[package]]
 name = "unsafe-libyaml"
 version = "0.2.5"

crates/pacdef_core/Cargo.toml

@@ -13,6 +13,7 @@ categories = ["command-line-utilities"]
 alpm = "2.2"
 anyhow = {workspace = true}
 clap = "4.1"
+const_format = { version = "0.2", default-features = false }
 path-absolutize = "3.0"
 regex = "1.7"
 termios = "0.3"
@@ -23,3 +24,4 @@ serde_derive = "1.0"
 serde = "1.0"
 
 pacdef_macros = {path = "../pacdef_macros", version = "0.1"}
+

crates/pacdef_core/src/core.rs

@@ -5,6 +5,7 @@ use std::path::Path;
 
 use anyhow::{anyhow, bail, ensure, Context, Result};
 use clap::ArgMatches;
+use const_format::formatcp;
 
 use crate::action::*;
 use crate::args;
@@ -338,11 +339,12 @@ fn show_error(error: &anyhow::Error, backend: &dyn Backend) {
 }
 
 pub const fn get_version_string() -> &'static str {
-    concat!(
-        "pacdef, version: ",
-        env!("CARGO_PKG_VERSION"),
-        " (",
-        env!("GIT_HASH"),
-        ")",
-    )
+    const VERSION: &str = concat!("pacdef, version: ", env!("CARGO_PKG_VERSION"));
+    const HASH: &str = env!("GIT_HASH");
+
+    if HASH.is_empty() {
+        VERSION
+    } else {
+        formatcp!("{VERSION} ({HASH})")
+    }
 }