Ensure consistent path normalisation

In particular, ensure that the empty path and "." have the
same normal form.

4 files changed, 42 insertions, 2 deletions

diff --git a/src/utils/cpp/path.hpp b/src/utils/cpp/path.hpp
index 045ece0e..aa2c8350 100644
--- a/src/utils/cpp/path.hpp
+++ b/src/utils/cpp/path.hpp
@@ -7,7 +7,10 @@
     -> std::filesystem::path {
     auto n = p.lexically_normal();
     if (not n.has_filename()) {
-        return n.parent_path();
+        n = n.parent_path();
+    }
+    if (n.empty()) {
+        return std::filesystem::path{"."};
     }
     return n;
 }
diff --git a/test/utils/TARGETS b/test/utils/TARGETS
index a0d637b1..c7c2f8fc 100644
--- a/test/utils/TARGETS
+++ b/test/utils/TARGETS
@@ -54,5 +54,9 @@
     ]
   , "stage": ["test", "utils"]
   }
-, "TESTS": {"type": "install", "tainted": ["test"]}
+, "TESTS":
+  { "type": "install"
+  , "tainted": ["test"]
+  , "dirs": [[["./", "cpp", "TESTS"], "cpp"]]
+  }
 }
diff --git a/test/utils/cpp/TARGETS b/test/utils/cpp/TARGETS
new file mode 100644
index 00000000..5e11d258
--- /dev/null
+++ b/test/utils/cpp/TARGETS
@@ -0,0 +1,13 @@
+{ "path":
+  { "type": ["@", "rules", "CC/test", "test"]
+  , "name": ["path"]
+  , "srcs": ["path.test.cpp"]
+  , "deps":
+    [ ["@", "catch2", "", "catch2"]
+    , ["test", "catch-main"]
+    , ["src/utils/cpp", "path"]
+    ]
+  , "stage": ["test", "utils", "cpp"]
+  }
+, "TESTS": {"type": "install", "tainted": ["test"], "deps": ["path"]}
+}
diff --git a/test/utils/cpp/path.test.cpp b/test/utils/cpp/path.test.cpp
new file mode 100644
index 00000000..b0e7eff8
--- /dev/null
+++ b/test/utils/cpp/path.test.cpp
@@ -0,0 +1,20 @@
+#include <filesystem>
+
+#include "catch2/catch.hpp"
+#include "src/utils/cpp/path.hpp"
+
+TEST_CASE("normalization", "[path]") {
+    CHECK(ToNormalPath(std::filesystem::path{""}) ==
+          ToNormalPath(std::filesystem::path{"."}));
+    CHECK(ToNormalPath(std::filesystem::path{""}).string() == ".");
+    CHECK(ToNormalPath(std::filesystem::path{"."}).string() == ".");
+
+    CHECK(ToNormalPath(std::filesystem::path{"foo/bar/.."}).string() == "foo");
+    CHECK(ToNormalPath(std::filesystem::path{"foo/bar/../"}).string() == "foo");
+    CHECK(ToNormalPath(std::filesystem::path{"foo/bar/../baz"}).string() ==
+          "foo/baz");
+    CHECK(ToNormalPath(std::filesystem::path{"./foo/bar"}).string() ==
+          "foo/bar");
+    CHECK(ToNormalPath(std::filesystem::path{"foo/.."}).string() == ".");
+    CHECK(ToNormalPath(std::filesystem::path{"./foo/.."}).string() == ".");
+}