3 files changed, 84 insertions, 1 deletions
diff --git a/test/buildtool/build_engine/target_map/TARGETS b/test/buildtool/build_engine/target_map/TARGETS
index 36799630..4c2eed56 100644
--- a/test/buildtool/build_engine/target_map/TARGETS
+++ b/test/buildtool/build_engine/target_map/TARGETS
@@ -26,6 +26,20 @@
     ]
   , "stage": ["test", "buildtool", "build_engine", "target_map"]
   }
+, "target_map_internals":
+  { "type": ["@", "rules", "CC/test", "test"]
+  , "name": ["target_map_internals"]
+  , "srcs": ["target_map_internals.test.cpp"]
+  , "deps":
+    [ ["@", "catch2", "", "catch2"]
+    , ["test", "catch-main"]
+    , [ "src/buildtool/build_engine/target_map"
+      , "target_map_testable_internals"
+      ]
+    , ["src/buildtool/build_engine/expression", "expression"]
+    ]
+  , "stage": ["test", "buildtool", "build_engine", "target_map"]
+  }
 , "test_data":
   { "type": ["@", "rules", "data", "staged"]
   , "srcs":
@@ -67,6 +81,6 @@
 , "TESTS":
   { "type": "install"
   , "tainted": ["test"]
-  , "deps": ["result_map", "target_map"]
+  , "deps": ["result_map", "target_map", "target_map_internals"]
   }
 }
diff --git a/test/buildtool/build_engine/target_map/target_map_internals.test.cpp b/test/buildtool/build_engine/target_map/target_map_internals.test.cpp
new file mode 100644
index 00000000..72d5b59c
--- /dev/null
+++ b/test/buildtool/build_engine/target_map/target_map_internals.test.cpp
@@ -0,0 +1,35 @@
+#include "catch2/catch.hpp"
+#include "src/buildtool/build_engine/expression/expression.hpp"
+#include "src/buildtool/build_engine/target_map/utils.hpp"
+
+TEST_CASE("Tree conflicts", "[tree_conflict]") {
+    auto overlap = Expression::FromJson(R"({ "foo/bar": "content-1"
+                            , "foo/bar/baz": "content-2"})"_json);
+    REQUIRE(overlap);
+    auto overlap_conflict = BuildMaps::Target::Utils::tree_conflict(overlap);
+    CHECK(overlap_conflict);
+    CHECK(*overlap_conflict == "foo/bar");
+
+    auto root_overlap = Expression::FromJson(R"({ ".": "content-1"
+                            , "foo": "content-2"})"_json);
+    REQUIRE(root_overlap);
+    auto root_overlap_conflict =
+        BuildMaps::Target::Utils::tree_conflict(root_overlap);
+    CHECK(root_overlap_conflict);
+    CHECK(*root_overlap_conflict == ".");
+}
+
+TEST_CASE("No conflict", "[tree_conflict]") {
+    auto no_overlap = Expression::FromJson(R"({ "foo/bar/baz.txt": "content-1"
+                            , "foo/bar/baz": "content-2"})"_json);
+    REQUIRE(no_overlap);
+    auto no_overlap_conflict =
+        BuildMaps::Target::Utils::tree_conflict(no_overlap);
+    CHECK(!no_overlap_conflict);
+
+    auto single_root = Expression::FromJson(R"({ ".": "content-1"})"_json);
+    REQUIRE(single_root);
+    auto single_root_conflict =
+        BuildMaps::Target::Utils::tree_conflict(single_root);
+    CHECK(!single_root_conflict);
+}
diff --git a/test/end-to-end/actions/conflicts.sh b/test/end-to-end/actions/conflicts.sh
index 089e742a..0adf0476 100755
--- a/test/end-to-end/actions/conflicts.sh
+++ b/test/end-to-end/actions/conflicts.sh
@@ -156,6 +156,35 @@ cat > RULES <<'EOI'
       }
     }
   }
+, "file-file-conflict":
+  { "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "map"
+        , { "type": "map_union"
+          , "$1":
+            [ { "type": "singleton_map"
+              , "key": "foo/bar/baz.txt"
+              , "value": {"type": "BLOB", "data": "Some content"}
+              }
+            , { "type": "singleton_map"
+              , "key": "foo/bar/baz.txt/other/file.txt"
+              , "value": {"type": "BLOB", "data": "A different content"}
+              }
+            ]
+          }
+        ]
+      , [ "out"
+        , { "type": "ACTION"
+          , "inputs": {"type": "var", "name": "map"}
+          , "outs": ["out"]
+          , "cmd": ["cp", "foo.txt", "out"]
+          }
+        ]
+      ]
+    , "body": {"type": "RESULT", "artifacts": {"type": "var", "name": "out"}}
+    }
+  }
 }
 EOI
 cat > TARGETS <<'EOI'
@@ -166,6 +195,7 @@ cat > TARGETS <<'EOI'
 , "input-tree-conflict": {"type": "input-tree-conflict"}
 , "artifacts-tree-conflict": {"type": "artifacts-tree-conflict"}
 , "runfiles-tree-conflict": {"type": "runfiles-tree-conflict"}
+, "file-file-conflict": {"type": "file-file-conflict"}
 }
 EOI
 
@@ -197,4 +227,8 @@ echo
 grep -i 'error.*runfiles.*conflict.*tree.*foo' log
 
 echo
+./bin/tool-under-test analyse -f log file-file-conflict 2>&1 && exit 1 || :
+grep -i 'error.*.*conflict.*foo/bar/baz.txt' log
+
+echo
 echo DONE