Fixed:

- Path dependencies now work correctly: `dcr add` stores them as `{ path =
"./..." }` tables, `is_registry_dep` properly distinguishes registry strings
from path/git strings, and `deps/mod.rs` resolves both table-form and
legacy string-form path dependencies
- Registry dependency paths no longer hardcoded to `project_root/dcr-index`;
now use `package_root_from_registry_info()` which resolves relative to the
registry cache root (`~/.dcr/`)
- Registry dependencies are now actually built: `build_project_at()` is
called when `include_dir` or `lib_dir` is missing

Added:

- `SIGINT`/`Ctrl+C` handler via `ctrlc` crate — `dcr build` now checks
`BUILD_INTERRUPTED` flag at key points and aborts cleanly
- `utils/build.rs` — extracted shared utilities: `parse_version_info`,
`normalize_target_os`, `resolve_compiler`, `primary_language`,
`resolve_pkg_config_flags` and config helpers. Eliminates code duplication
between `cli/build.rs`, `cli/run.rs`, `cli/clean.rs`, `cli/gen.rs`
- `utils/fs.rs::with_dir` — extracted common directory-scoped execution
- `run_command_sync_output` in `builder/common.rs` with global `OUTPUT_MUTEX`
— synchronized compiler output across all backends (unix_cc, gas, nasm, msvc)
- New helper functions in `deps/register.rs`: `get_registry_cache_root`,
`package_root_from_registry_info`, `registry_include_dir`, `registry_lib_dir`,
`path_from_string_dep`
- Unit tests for `register.rs` (`is_registry_dep`, `package_root_from_registry_info`),
`deps/mod.rs` (`path_dep_path`, `push_default_lib_dirs`),
`utils/build.rs` (`normalize_target_os`, `parse_version_info`)

Removed:

- Removed unused dependencies `indicatif` and `console` from `Cargo.toml`

tests/cli_basic.rs

@@ -232,7 +232,7 @@ fn dcr_add_dependencies() {
     assert!(out.status.success(), "dcr add path should succeed");
     let toml = std::fs::read_to_string(dir.join("dcr.toml")).unwrap();
     assert!(
-        toml.contains("mylib = \"./libs/mylib\""),
+        toml.contains("mylib = { path = \"./libs/mylib\" }"),
         "path dep not found in toml"
     );
 
@@ -316,6 +316,85 @@ fn dcr_builds_lib_package() {
     assert!(target_dir.join("lib").exists(), "lib directory missing");
 }
 
+#[test]
+fn registry_dependency_is_built_from_cache() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping registry dependency build test");
+        return;
+    };
+
+    let root = unique_sandbox_dir("registry_dep");
+    let home = root.join("home");
+    let dcr_home = home.join(".dcr");
+    let dep = root.join("cache").join("mylib");
+    let app = root.join("app");
+    std::fs::create_dir_all(dcr_home.as_path()).expect("failed to create dcr home");
+    std::fs::create_dir_all(dep.join("src")).expect("failed to create dep src");
+    std::fs::create_dir_all(app.join("src")).expect("failed to create app src");
+
+    std::fs::write(
+        dcr_home.join("config.toml"),
+        "[registry.local]\nurl = \"file://local\"\npriority = 1\n",
+    )
+    .expect("failed to write registry config");
+    std::fs::write(
+        dcr_home.join("index.json"),
+        format!(
+            "{{\"packages\":[{{\"name\":\"mylib\",\"latest_version\":\"0.1.0\",\"path\":\"{}\"}}]}}",
+            dep.display()
+        ),
+    )
+    .expect("failed to write registry index");
+
+    std::fs::write(
+        dep.join("dcr.toml"),
+        "[package]\nname = \"mylib\"\nversion = \"0.1.0\"\ntype = \"lib\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"staticlib\"\n\n[dependencies]\n",
+    )
+    .expect("failed to write dep dcr.toml");
+    std::fs::write(dep.join("src").join("mylib.h"), "int answer(void);\n")
+        .expect("failed to write header");
+    std::fs::write(
+        dep.join("src").join("mylib.c"),
+        "int answer(void) { return 42; }\n",
+    )
+    .expect("failed to write dep source");
+
+    std::fs::write(
+        app.join("dcr.toml"),
+        "[package]\nname = \"app\"\nversion = \"0.1.0\"\ntype = \"none\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"bin\"\n\n[dependencies]\nmylib = \"0.1.0\"\n",
+    )
+    .expect("failed to write app dcr.toml");
+    std::fs::write(
+        app.join("src").join("main.c"),
+        "#include \"mylib.h\"\nint main(void) { return answer() == 42 ? 0 : 1; }\n",
+    )
+    .expect("failed to write app source");
+
+    let index_path = dcr_home.join("index.json");
+    let envs = [
+        ("DCR_COMPILER", compiler),
+        ("HOME", home.to_str().unwrap()),
+        ("DCR_INDEX_PATH", index_path.to_str().unwrap()),
+    ];
+    let out = run_dcr_env(&["build"], &app, &envs);
+    if !out.status.success() {
+        eprintln!("stdout: {}", String::from_utf8_lossy(&out.stdout));
+        eprintln!("stderr: {}", String::from_utf8_lossy(&out.stderr));
+    }
+    assert!(
+        out.status.success(),
+        "registry dependency build should succeed"
+    );
+    assert!(
+        dep.join("target").join("include").join("mylib.h").is_file(),
+        "registry dependency headers were not packaged"
+    );
+    assert!(
+        dep.join("target").join("lib").exists(),
+        "registry dependency library directory missing"
+    );
+}
+
 #[test]
 fn dcr_test_runs_without_sandbox_dependency() {
     let Some(compiler) = available_compiler() else {