build: revise dep graph for version changes

Previously, the config crate would get rebuilt each time the
git state changed, which has a lot of fan out and makes the build
take longer than it really needs to.

This commit breaks out the version changing stuff to its own crate
and then provides a runtime mechanism for assigning the version
information back into the config crate.

The env-bootstrap crate is responsible for setting that up.

Cargo.lock

@@ -846,7 +846,6 @@ dependencies = [
  "dirs-next",
  "enum-display-derive",
  "env_logger",
- "git2",
  "hostname",
  "lazy_static",
  "libc",
@@ -855,6 +854,7 @@ dependencies = [
  "mlua",
  "nix 0.26.2",
  "notify",
+ "once_cell",
  "ordered-float",
  "portable-pty",
  "promise",
@@ -1482,6 +1482,7 @@ dependencies = [
  "termwiz",
  "termwiz-funcs",
  "time-funcs",
+ "wezterm-version",
  "winapi",
 ]
 
@@ -6256,6 +6257,13 @@ dependencies = [
  "zvariant",
 ]
 
+[[package]]
+name = "wezterm-version"
+version = "0.1.0"
+dependencies = [
+ "git2",
+]
+
 [[package]]
 name = "wgpu"
 version = "0.15.1"

config/Cargo.toml

@@ -3,16 +3,12 @@ name = "config"
 version = "0.1.0"
 authors = ["Wez Furlong <wez@wezfurlong.org>"]
 edition = "2018"
-build = "build.rs"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dev-dependencies]
 env_logger = "0.10"
 
-[build-dependencies]
-git2 = { version = "0.16", default-features = false }
-
 [features]
 distro-defaults = []
 
@@ -30,6 +26,7 @@ luahelper = { path = "../luahelper" }
 mlua = {version="0.8.3", features=["vendored", "lua54", "async", "send"]}
 # file change notification
 notify = "5.0.0"
+once_cell = "1.8"
 ordered-float = { version = "3.0", features = ["serde"] }
 portable-pty = { path = "../pty", features = ["serde_support"]}
 promise = { path = "../promise" }

config/src/version.rs

@@ -1,11 +1,23 @@
+use once_cell::sync::OnceCell;
+
+static VERSION: OnceCell<&'static str> = OnceCell::new();
+static TRIPLE: OnceCell<&'static str> = OnceCell::new();
+
+pub fn assign_version_info(version: &'static str, triple: &'static str) {
+    VERSION.set(version).unwrap();
+    TRIPLE.set(triple).unwrap();
+}
+
 pub fn wezterm_version() -> &'static str {
-    // See build.rs
-    env!("WEZTERM_CI_TAG")
+    VERSION
+        .get()
+        .unwrap_or(&"someone forgot to call assign_version_info")
 }
 
 pub fn wezterm_target_triple() -> &'static str {
-    // See build.rs
-    env!("WEZTERM_TARGET_TRIPLE")
+    TRIPLE
+        .get()
+        .unwrap_or(&"someone forgot to call assign_version_info")
 }
 
 pub fn running_under_wsl() -> bool {

env-bootstrap/Cargo.toml

@@ -29,6 +29,7 @@ share-data = { path = "../lua-api-crates/share-data" }
 ssh-funcs = { path = "../lua-api-crates/ssh-funcs" }
 spawn-funcs = { path = "../lua-api-crates/spawn-funcs" }
 time-funcs = { path = "../lua-api-crates/time-funcs" }
+wezterm-version = { path = "../wezterm-version" }
 
 [target."cfg(windows)".dependencies]
 winapi = "0.3"

env-bootstrap/src/lib.rs

@@ -184,6 +184,10 @@ fn register_lua_modules() {
 }
 
 pub fn bootstrap() {
+    config::assign_version_info(
+        wezterm_version::wezterm_version(),
+        wezterm_version::wezterm_target_triple(),
+    );
     setup_logger();
     register_panic_hook();
 

wezterm-version/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "wezterm-version"
+version = "0.1.0"
+edition = "2021"
+build = "build.rs"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+git2 = { version = "0.16", default-features = false }
+
+[dependencies]

wezterm-version/build.rs

@@ -1,5 +1,3 @@
-use std::path::Path;
-
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
@@ -30,12 +28,7 @@ fn main() {
                     }
                 }
             }
-        }
 
-        let head = Path::new("../.git/HEAD");
-        if head.exists() {
-            let head = head.canonicalize().unwrap();
-            println!("cargo:rerun-if-changed={}", head.display());
             if let Ok(output) = std::process::Command::new("git")
                 .args(&[
                     "-c",
@@ -57,5 +50,4 @@ fn main() {
 
     println!("cargo:rustc-env=WEZTERM_TARGET_TRIPLE={}", target);
     println!("cargo:rustc-env=WEZTERM_CI_TAG={}", ci_tag);
-    println!("cargo:rustc-env=MACOSX_DEPLOYMENT_TARGET=10.9");
 }

wezterm-version/src/lib.rs

@@ -0,0 +1,9 @@
+pub fn wezterm_version() -> &'static str {
+    // See build.rs
+    env!("WEZTERM_CI_TAG")
+}
+
+pub fn wezterm_target_triple() -> &'static str {
+    // See build.rs
+    env!("WEZTERM_TARGET_TRIPLE")
+}