Fail builds when required Windows resource embedding fails (#427)

The app build scripts stop the build when required Windows resources fail to embed (cargo::error instead of the ignored cargo:error). Fixes #264.

apps/craft-anything-cli/build.rs

@@ -22,7 +22,7 @@ fn main() {
     res.set_manifest(MANIFEST).set("OriginalFilename", "craft-anything-cli.exe").set("InternalName", "craft-anything-cli");
     if let Err(e) = res.compile() {
         if std::env::var_os("CRAFT_ANYTHING_REQUIRE_WINRES").is_some() {
-            println!("cargo:error=embedding Windows resources failed: {e}");
+            println!("cargo::error=embedding Windows resources failed: {e}");
             return;
         }
         println!("cargo:warning=craft-anything-cli.exe built without its DPI-aware manifest: {e}");

apps/craft-anything-cli/tests/build_scripts.rs

@@ -0,0 +1,19 @@
+//! The app build scripts must fail the build (Cargo's `cargo::error` instruction) when Windows
+//! resources are required. The single-colon `cargo:error=` form is ignored by Cargo as metadata.
+
+use std::path::Path;
+
+fn read(rel: &str) -> String {
+    let path = Path::new(env!("CARGO_MANIFEST_DIR")).join(rel);
+    std::fs::read_to_string(&path).unwrap_or_default()
+}
+
+#[test]
+fn required_windows_resource_failure_uses_cargo_error_directive() {
+    for rel in ["build.rs", "../craft-anything/build.rs"] {
+        let src = read(rel);
+        assert!(!src.is_empty(), "{rel} should be readable");
+        assert!(!src.contains("cargo:error="), "{rel} emits the ignored single-colon error directive");
+        assert!(src.contains("cargo::error="), "{rel} must emit cargo::error= when resources are required");
+    }
+}

apps/craft-anything/build.rs

@@ -20,7 +20,7 @@ fn main() {
         .set("InternalName", "craft-anything");
     if let Err(e) = res.compile() {
         if std::env::var_os("CRAFT_ANYTHING_REQUIRE_WINRES").is_some() {
-            println!("cargo:error=embedding Windows resources failed: {e}");
+            println!("cargo::error=embedding Windows resources failed: {e}");
             return;
         }
         println!("cargo:warning=craft-anything.exe built without icon/version resources: {e}");