Merge pull request #547 from biojppm/fix/firstdocseq

fix Tree::set_root_as_stream() when the original root is an empty seq
2026-01-18 21:41:18 +01:00 · 2025-10-02 22:25:20 +01:00
parent dd87caa7da 177bf53011
commit 739e931210
5 changed files with 216 additions and 15 deletions
--- a/changelog/current.md
+++ b/changelog/current.md
@@ -0,0 +1,8 @@
+### Changes
+
+- [PR#547](https://github.com/biojppm/rapidyaml/pull/547) - Fix parsing of implicit first documents with empty sequences, caused by a problem in `Tree::set_root_as_stream()`:
+  ```yaml
+  []  # this container was lost during parsing
+  ---
+  more data here
+  ```
--- a/src/c4/yml/event_handler_tree.hpp
+++ b/src/c4/yml/event_handler_tree.hpp
@@ -190,7 +190,7 @@ public:
            id_type first = m_tree->first_child(m_tree->root_id());
            _RYML_CB_ASSERT(m_stack.m_callbacks, m_tree->is_stream(m_tree->root_id()));
            _RYML_CB_ASSERT(m_stack.m_callbacks, m_tree->num_children(m_tree->root_id()) == 1u);
-            if(m_tree->has_children(first) || m_tree->is_val(first))
+            if(m_tree->is_container(first) || m_tree->is_val(first))
            {
                _c4dbgp("push!");
                _push();
@@ -693,15 +693,10 @@ public:
        _c4dbgp("set root as stream");
        _RYML_CB_ASSERT(m_tree->callbacks(), m_tree->root_id() == 0u);
        _RYML_CB_ASSERT(m_tree->callbacks(), m_curr->node_id == 0u);
-        const bool hack = !m_tree->has_children(m_curr->node_id) && !m_tree->is_val(m_curr->node_id);
-        if(hack)
-            m_tree->_p(m_tree->root_id())->m_type.add(VAL);
        m_tree->set_root_as_stream();
        _RYML_CB_ASSERT(m_tree->callbacks(), m_tree->is_stream(m_tree->root_id()));
        _RYML_CB_ASSERT(m_tree->callbacks(), m_tree->has_children(m_tree->root_id()));
        _RYML_CB_ASSERT(m_tree->callbacks(), m_tree->is_doc(m_tree->first_child(m_tree->root_id())));
-        if(hack)
-            m_tree->_p(m_tree->first_child(m_tree->root_id()))->m_type.rem(VAL);
        _set_state_(m_curr, m_tree->root_id());
    }

--- a/src/c4/yml/tree.cpp
+++ b/src/c4/yml/tree.cpp
@@ -825,7 +825,13 @@ void Tree::set_root_as_stream()
    // don't use _add_flags() because it's checked and will fail
    if(!has_children(root))
    {
-        if(is_val(root))
+        if(is_container(root))
+        {
+            id_type next_doc = append_child(root);
+            _copy_props_wo_key(next_doc, root);
+            _p(next_doc)->m_type.add(DOC);
+        }
+        else
        {
            _p(root)->m_type.add(SEQ);
            id_type next_doc = append_child(root);
--- a/test/test_engine_1_doc.cpp
+++ b/test/test_engine_1_doc.cpp
@@ -909,10 +909,10 @@ ENGINE_TEST(DocStream,

 //-----------------------------------------------------------------------------

-ENGINE_TEST(DocStreamImplicitDocFirst,
-            "doc0\n--- doc1\n--- doc2\n"
+ENGINE_TEST(DocStreamImplicitDocFirstVal,
+            "doc0\n--- doc1\n"
            ,
-            "--- doc0\n--- doc1\n--- doc2\n"
+            "--- doc0\n--- doc1\n"
            ,
            "+STR\n"
            "+DOC\n"
@@ -921,9 +921,6 @@ ENGINE_TEST(DocStreamImplicitDocFirst,
            "+DOC ---\n"
            "=VAL :doc1\n"
            "-DOC\n"
-            "+DOC ---\n"
-            "=VAL :doc2\n"
-            "-DOC\n"
            "-STR\n")
 {
    ___(ps.begin_stream());
@@ -933,8 +930,201 @@ ENGINE_TEST(DocStreamImplicitDocFirst,
    ___(ps.begin_doc_expl());
    ___(ps.set_val_scalar_plain("doc1"));
    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstAnchor,
+            "&anch1\n"
+            "--- &anch2\n"
+            ,
+            "--- &anch1 \n"
+            "--- &anch2 \n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "=VAL &anch1 :\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "=VAL &anch2 :\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.set_val_anchor("anch1"));
+    ___(ps.set_val_scalar_plain_empty());
+    ___(ps.end_doc());
    ___(ps.begin_doc_expl());
-    ___(ps.set_val_scalar_plain("doc2"));
+    ___(ps.set_val_anchor("anch2"));
+    ___(ps.set_val_scalar_plain_empty());
+    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstTag,
+            "!!str\n"
+            "--- !!str\n"
+            ,
+            "--- !!str \n"
+            "--- !!str \n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "=VAL <tag:yaml.org,2002:str> :\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "=VAL <tag:yaml.org,2002:str> :\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.set_val_tag("!!str"));
+    ___(ps.set_val_scalar_plain_empty());
+    ___(ps.end_doc());
+    ___(ps.begin_doc_expl());
+    ___(ps.set_val_tag("!!str"));
+    ___(ps.set_val_scalar_plain_empty());
+    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstSeqFlowEmpty,
+            "[]\n"
+            "--- []\n"
+            ,
+            "---\n"
+            "[]\n"
+            "---\n"
+            "[]\n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "+SEQ []\n"
+            "-SEQ\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "+SEQ []\n"
+            "-SEQ\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.begin_seq_val_flow());
+    ___(ps.end_seq());
+    ___(ps.end_doc());
+    ___(ps.begin_doc_expl());
+    ___(ps.begin_seq_val_flow());
+    ___(ps.end_seq());
+    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstSeqFlow,
+            "[a]\n"
+            "--- [b]\n"
+            ,
+            "---\n"
+            "[a]\n"
+            "---\n"
+            "[b]\n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "+SEQ []\n"
+            "=VAL :a\n"
+            "-SEQ\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "+SEQ []\n"
+            "=VAL :b\n"
+            "-SEQ\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.begin_seq_val_flow());
+    ___(ps.set_val_scalar_plain("a"));
+    ___(ps.end_seq());
+    ___(ps.end_doc());
+    ___(ps.begin_doc_expl());
+    ___(ps.begin_seq_val_flow());
+    ___(ps.set_val_scalar_plain("b"));
+    ___(ps.end_seq());
+    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstMapEmpty,
+            "{}\n"
+            "--- {}\n"
+            ,
+            "---\n"
+            "{}\n"
+            "---\n"
+            "{}\n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "+MAP {}\n"
+            "-MAP\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "+MAP {}\n"
+            "-MAP\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.begin_map_val_flow());
+    ___(ps.end_map());
+    ___(ps.end_doc());
+    ___(ps.begin_doc_expl());
+    ___(ps.begin_map_val_flow());
+    ___(ps.end_map());
+    ___(ps.end_doc());
+    ___(ps.end_stream());
+}
+
+ENGINE_TEST(DocStreamImplicitDocFirstMap,
+            "{a: b}\n"
+            "--- {c: d}\n"
+            ,
+            "---\n"
+            "{a: b}\n"
+            "---\n"
+            "{c: d}\n"
+            ,
+            "+STR\n"
+            "+DOC\n"
+            "+MAP {}\n"
+            "=VAL :a\n"
+            "=VAL :b\n"
+            "-MAP\n"
+            "-DOC\n"
+            "+DOC ---\n"
+            "+MAP {}\n"
+            "=VAL :c\n"
+            "=VAL :d\n"
+            "-MAP\n"
+            "-DOC\n"
+            "-STR\n")
+{
+    ___(ps.begin_stream());
+    ___(ps.begin_doc());
+    ___(ps.begin_map_val_flow());
+    ___(ps.set_key_scalar_plain("a"));
+    ___(ps.set_val_scalar_plain("b"));
+    ___(ps.end_map());
+    ___(ps.end_doc());
+    ___(ps.begin_doc_expl());
+    ___(ps.begin_map_val_flow());
+    ___(ps.set_key_scalar_plain("c"));
+    ___(ps.set_val_scalar_plain("d"));
+    ___(ps.end_map());
    ___(ps.end_doc());
    ___(ps.end_stream());
 }
--- a/test/test_tree.cpp
+++ b/test/test_tree.cpp
@@ -4132,8 +4132,10 @@ TEST(set_root_as_stream, empty_tree)
    EXPECT_EQ(r.is_stream(), false);
    EXPECT_EQ(r.num_children(), 0u);
    t.set_root_as_stream();
+    r = t.rootref();
    EXPECT_EQ(r.is_stream(), true);
-    EXPECT_EQ(r.num_children(), 0u);
+    ASSERT_EQ(r.num_children(), 1u);
+    EXPECT_EQ(r[0].is_doc(), 1u);
 }

 TEST(set_root_as_stream, already_with_stream)