Enable cargo env vars when there is no .git

But still disable git env vars.

This change requires vergen 5.1.4 or later.

Cargo.lock

@@ -1397,9 +1397,9 @@ checksum = "f6503fe142514ca4799d4c26297c4248239fe8838d827db6bd6065c6ed29a6ce"
 
 [[package]]
 name = "git2"
-version = "0.13.17"
+version = "0.13.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d250f5f82326884bd39c2853577e70a121775db76818ffa452ed1e80de12986"
+checksum = "b483c6c2145421099df1b4efd50e0f6205479a072199460eff852fa15e5603c7"
 dependencies = [
  "bitflags",
  "libc",
@@ -1873,9 +1873,9 @@ checksum = "9385f66bf6105b241aa65a61cb923ef20efc665cb9f9bb50ac2f0c4b7f378d41"
 
 [[package]]
 name = "libgit2-sys"
-version = "0.12.18+1.1.0"
+version = "0.12.19+1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3da6a42da88fc37ee1ecda212ffa254c25713532980005d5f7c0b0fbe7e6e885"
+checksum = "f322155d574c8b9ebe991a04f6908bb49e68a79463338d24a43d6274cb6443e6"
 dependencies = [
  "cc",
  "libc",
@@ -4052,9 +4052,9 @@ checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
 [[package]]
 name = "vergen"
-version = "5.1.2"
+version = "5.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0277ffac28b64e449a7a8c369ddd8591647c5a2d1fd513eebd6a153ff4c40ea4"
+checksum = "575b693376dacf6a9825ab3e61a033cf0e94040e620fca8447b055ef8ce82d2b"
 dependencies = [
  "anyhow",
  "cfg-if 1.0.0",

zebrad/Cargo.toml

@@ -48,7 +48,7 @@ sentry = { version = "0.21.0", default-features = false, features = ["backtrace"
 sentry-tracing = { git = "https://github.com/kellpossible/sentry-tracing.git", rev = "f1a4a4a16b5ff1022ae60be779eb3fb928ce9b0f" }
 
 [build-dependencies]
-vergen = { version = "5.1.2", default-features = false, features = ["cargo", "git"] }
+vergen = { version = "5.1.4", default-features = false, features = ["cargo", "git"] }
 
 [dev-dependencies]
 abscissa_core = { version = "0.5", features = ["testing"] }

zebrad/build.rs

@@ -1,18 +1,47 @@
-use vergen::{vergen, Config, ShaKind};
+use vergen::{vergen, Config, SemverKind, ShaKind};
+
+/// Disable vergen env vars that could cause spurious reproducible build
+/// failures
+fn disable_non_reproducible(_config: &mut Config) {
+    /*
+    Currently, these features are disabled in `Cargo.toml`
+
+    // We don't use build or host-specific env vars, because they can break
+    // reproducible builds.
+    *config.build_mut().enabled_mut() = false;
+    *config.rustc mut().host_triple_mut() = false;
+
+    // It's ok for reproducible builds to depend on the build OS. But most other
+    // sysinfo should not change reproducible builds, so we disable it.
+    *config.sysinfo mut().user_mut() = false;
+    *config.sysinfo mut().memory_mut() = false;
+    *config.sysinfo mut().cpu_vendor_mut() = false;
+    *config.sysinfo mut().cpu_core_count_mut() = false;
+    *config.sysinfo mut().cpu_name_mut() = false;
+    *config.sysinfo mut().cpu_brand_mut() = false;
+    *config.sysinfo mut().cpu_frequency_mut() = false;
+     */
+}
 
 fn main() {
     let mut config = Config::default();
-
-    *config.cargo_mut().features_mut() = false;
-    *config.cargo_mut().profile_mut() = false;
+    disable_non_reproducible(&mut config);
 
     *config.git_mut().sha_kind_mut() = ShaKind::Short;
 
+    // Disable env vars we aren't using right now
+    *config.cargo_mut().features_mut() = false;
+
+    // Disable git if we're building with an invalid `zebra/.git`
     match vergen(config) {
         Ok(_) => {}
-        Err(e) => eprintln!(
-            "skipping detailed git and target info due to vergen error: {:?}",
-            e
-        ),
+        Err(e) => {
+            eprintln!(
+                "git error in vergen build script: skipping git env vars: {:?}",
+                e
+            );
+            *config.git_mut().enabled_mut() = false;
+            vergen(config).expect("non-git vergen should succeed");
+        }
     }
 }

zebrad/src/application.rs

@@ -220,6 +220,8 @@ impl Application for ZebradApp {
             // cargo or git tag + short commit
             ("version", Some(app_version().to_string())),
             // git
+            // git env vars can be skipped if there is no `.git` during the
+            // build, so they must all be optional
             ("branch", option_env!("VERGEN_GIT_BRANCH").map(Into::into)),
             ("git commit", Self::git_commit().map(Into::into)),
             (