feat(lsp): add call hierarchy support for TCL and MOM

Adds LSP call hierarchy support for TCL procedures and MOM events.
A symbol index and identity logic underpin incoming and outgoing calls.
LSP call hierarchy features are wired and changelog/README updated.

- Implement data encoding for call hierarchy items and identity restoration
- Wire LSP server to expose prepare_call_hierarchy, incoming_calls, and outgoing_calls
- Add tests for cross-file calls and edge cases

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Unreleased
 
+- Add incoming and outgoing call hierarchy for custom TCL procedures and MOM event handlers
 - Integrate the NX Tcl Remote Debugger directly into NX Postprocessor Support
 - Add `nx-tcl` attach configurations and breakpoint support for TCL and DEF files
 - Support breakpoints, stepping, stack frames, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops

README.md

@@ -10,6 +10,7 @@ A comprehensive VS Code extension providing language support and remote debuggin
 - **Intelligent Code Analysis** - Linting and error detection for postprocessor code
 - **Auto-completion** - Context-aware code completion for faster development
 - **Signature Help** - Shows parameters and documentation for custom and NX procedures
+- **Call Hierarchy** - Traces incoming and outgoing calls between custom TCL procedures and MOM event handlers
 - **NX Tcl Remote Debugger** - Breakpoints, stepping, call stack, scopes, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops directly in a running NX Post process
 
 ## Supported File Types
@@ -96,6 +97,7 @@ Simply open any supported file type and enjoy:
 - Code formatting (Format Document command)
 - Hover information
 - Signature help while entering procedure arguments
+- Incoming and outgoing call hierarchy for custom procedures and MOM event handlers
 - Remote NX Tcl debugging with breakpoints and full stepping
 
 ## Contributing

server/src/lsp_server.py

@@ -51,8 +51,12 @@ from tools.inlay_hint import (
 )
 from tools.navigation import (
     SymbolIdentity,
+    call_hierarchy_identity,
+    call_hierarchy_items,
     definition_identities,
+    incoming_call_hierarchy,
     matching_occurrences,
+    outgoing_call_hierarchy,
     symbol_at_position,
     workspace_symbols,
 )
@@ -629,6 +633,45 @@ def workspace_symbol(params: lsp.WorkspaceSymbolParams):
     return workspace_symbols(LSP_SERVER.navigation_snapshot(), params.query)
 
 
+@LSP_SERVER.feature(lsp.TEXT_DOCUMENT_PREPARE_CALL_HIERARCHY)
+def prepare_call_hierarchy(params: lsp.CallHierarchyPrepareParams):
+    context = _navigation_context(params.text_document.uri, params.position)
+    if context is None:
+        return None
+
+    indexes, _, _, identity = context
+    items = call_hierarchy_items(identity, indexes)
+    return items or None
+
+
+@LSP_SERVER.feature(lsp.CALL_HIERARCHY_INCOMING_CALLS)
+def incoming_calls(params: lsp.CallHierarchyIncomingCallsParams):
+    identity = call_hierarchy_identity(params.item)
+    if identity is None:
+        return []
+
+    indexes = LSP_SERVER.navigation_snapshot()
+    return incoming_call_hierarchy(
+        identity,
+        indexes,
+        definition_identities(indexes),
+    )
+
+
+@LSP_SERVER.feature(lsp.CALL_HIERARCHY_OUTGOING_CALLS)
+def outgoing_calls(params: lsp.CallHierarchyOutgoingCallsParams):
+    identity = call_hierarchy_identity(params.item)
+    if identity is None:
+        return []
+
+    indexes = LSP_SERVER.navigation_snapshot()
+    return outgoing_call_hierarchy(
+        identity,
+        indexes,
+        definition_identities(indexes),
+    )
+
+
 # **********************************************************
 # Linting features end here
 # **********************************************************
@@ -704,6 +747,7 @@ def initialize(params: lsp.InitializeParams) -> lsp.InitializeResult:
             references_provider=True,
             rename_provider=lsp.RenameOptions(prepare_provider=True),
             workspace_symbol_provider=True,
+            call_hierarchy_provider=True,
         )
     )
 

server/src/tools/navigation.py

@@ -1,10 +1,10 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
+from pathlib import Path
 
 import lsprotocol.types as lsp
-from tclint.syntax_tree import BareWord, Command, List, Node, Script, VarSub
+from tclint.syntax_tree import Command, List, Node, Script, VarSub
-
 
 ROOT_NAMESPACE = "::"
 
@@ -25,6 +25,8 @@ class SymbolOccurrence:
     symbol_kind: lsp.SymbolKind = lsp.SymbolKind.Variable
     container_name: str | None = None
     fallback_identity: SymbolIdentity | None = None
+    caller: SymbolIdentity | None = None
+    declaration_range: lsp.Range | None = None
 
 
 @dataclass(frozen=True)
@@ -32,6 +34,7 @@ class FileSymbolIndex:
     path: str
     uri: str
     occurrences: tuple[SymbolOccurrence, ...]
+    document_range: lsp.Range | None = None
 
 
 @dataclass(frozen=True)
@@ -105,6 +108,18 @@ def _name_range(node: Node, raw_name: str, *, variable_sub: bool = False) -> lsp
     )
 
 
+def _node_range(node: Node) -> lsp.Range | None:
+    if node.pos is None or node.end_pos is None:
+        return None
+    return lsp.Range(
+        start=lsp.Position(line=node.pos[0] - 1, character=node.pos[1] - 1),
+        end=lsp.Position(
+            line=node.end_pos[0] - 1,
+            character=node.end_pos[1] - 1,
+        ),
+    )
+
+
 def _proc_identity(raw_name: str, namespace: str) -> SymbolIdentity:
     return SymbolIdentity(kind="proc", name=_qualify(raw_name, namespace))
 
@@ -251,8 +266,16 @@ def build_file_symbol_index(
         scope: _Scope,
         *,
         is_definition: bool,
+        declaration_range: lsp.Range | None = None,
     ) -> None:
         identity = _proc_identity(raw_name, scope.namespace)
+        caller = None
+        if not is_definition:
+            caller = (
+                SymbolIdentity(kind="proc", name=scope.proc_name)
+                if scope.proc_name is not None
+                else SymbolIdentity(kind="file", name=filepath)
+            )
         occurrences.append(
             SymbolOccurrence(
                 identity=identity,
@@ -266,6 +289,8 @@ def build_file_symbol_index(
                 is_definition=is_definition,
                 symbol_kind=lsp.SymbolKind.Function,
                 container_name=_container_name(identity),
+                caller=caller,
+                declaration_range=declaration_range,
             )
         )
 
@@ -319,7 +344,13 @@ def build_file_symbol_index(
         if raw_name is None or not isinstance(body, Script):
             return
 
-        add_proc(command.args[0], raw_name, scope, is_definition=True)
+        add_proc(
+            command.args[0],
+            raw_name,
+            scope,
+            is_definition=True,
+            declaration_range=_node_range(command),
+        )
         proc_identity = _proc_identity(raw_name, scope.namespace)
         proc_namespace = _namespace_of(proc_identity.name)
         global_variables, namespace_variables = _scan_proc_imports(
@@ -435,7 +466,12 @@ def build_file_symbol_index(
             walk_embedded(child, scope)
 
     walk_script(tree, _Scope(filepath=filepath))
-    return FileSymbolIndex(path=filepath, uri=uri, occurrences=tuple(occurrences))
+    return FileSymbolIndex(
+        path=filepath,
+        uri=uri,
+        occurrences=tuple(occurrences),
+        document_range=_node_range(tree),
+    )
 
 
 def definition_identities(indexes: dict[str, FileSymbolIndex]) -> set[SymbolIdentity]:
@@ -517,3 +553,215 @@ def workspace_symbols(
                 )
             )
     return sorted(results, key=lambda symbol: symbol.name.casefold())
+
+
+_CALL_HIERARCHY_DATA_KIND = "nx-post-support.call-hierarchy"
+
+
+def _call_hierarchy_data(identity: SymbolIdentity) -> dict[str, str]:
+    return {
+        "source": _CALL_HIERARCHY_DATA_KIND,
+        "kind": identity.kind,
+        "name": identity.name,
+    }
+
+
+def call_hierarchy_identity(item: lsp.CallHierarchyItem) -> SymbolIdentity | None:
+    """Restore the symbol identity carried by a call hierarchy item."""
+    data = item.data
+    if (
+        not isinstance(data, dict)
+        or data.get("source") != _CALL_HIERARCHY_DATA_KIND
+    ):
+        return None
+
+    kind = data.get("kind")
+    name = data.get("name")
+    if kind not in {"proc", "file"} or not isinstance(name, str):
+        return None
+    return SymbolIdentity(kind=kind, name=name)
+
+
+def _proc_definitions(
+    indexes: dict[str, FileSymbolIndex],
+) -> dict[SymbolIdentity, list[tuple[FileSymbolIndex, SymbolOccurrence]]]:
+    definitions: dict[
+        SymbolIdentity, list[tuple[FileSymbolIndex, SymbolOccurrence]]
+    ] = {}
+    for index in indexes.values():
+        for occurrence in index.occurrences:
+            if occurrence.is_definition and occurrence.identity.kind == "proc":
+                definitions.setdefault(occurrence.identity, []).append(
+                    (index, occurrence)
+                )
+    return definitions
+
+
+def _unique_proc_definition(
+    identity: SymbolIdentity,
+    proc_definitions: dict[
+        SymbolIdentity, list[tuple[FileSymbolIndex, SymbolOccurrence]]
+    ],
+) -> tuple[FileSymbolIndex, SymbolOccurrence] | None:
+    matches = proc_definitions.get(identity, [])
+    if len(matches) != 1:
+        return None
+    return matches[0]
+
+
+def _file_item(
+    identity: SymbolIdentity,
+    indexes: dict[str, FileSymbolIndex],
+) -> lsp.CallHierarchyItem | None:
+    if identity.kind != "file":
+        return None
+    index = indexes.get(identity.name)
+    if index is None:
+        return None
+
+    range_ = index.document_range or lsp.Range(
+        start=lsp.Position(line=0, character=0),
+        end=lsp.Position(line=0, character=0),
+    )
+    selection_range = lsp.Range(start=range_.start, end=range_.start)
+    return lsp.CallHierarchyItem(
+        name=Path(index.path).name,
+        kind=lsp.SymbolKind.File,
+        uri=index.uri,
+        range=range_,
+        selection_range=selection_range,
+        detail=str(Path(index.path).parent),
+        data=_call_hierarchy_data(identity),
+    )
+
+
+def _call_hierarchy_item(
+    identity: SymbolIdentity,
+    indexes: dict[str, FileSymbolIndex],
+    proc_definitions: dict[
+        SymbolIdentity, list[tuple[FileSymbolIndex, SymbolOccurrence]]
+    ],
+) -> lsp.CallHierarchyItem | None:
+    if identity.kind == "file":
+        return _file_item(identity, indexes)
+
+    definition = _unique_proc_definition(identity, proc_definitions)
+    if definition is None:
+        return None
+
+    index, occurrence = definition
+    basename = _basename(identity.name)
+    symbol_kind = (
+        lsp.SymbolKind.Event
+        if basename.startswith("MOM_")
+        else lsp.SymbolKind.Function
+    )
+    return lsp.CallHierarchyItem(
+        name=_display_name(identity),
+        kind=symbol_kind,
+        uri=index.uri,
+        range=occurrence.declaration_range or occurrence.range,
+        selection_range=occurrence.range,
+        detail=Path(index.path).name,
+        data=_call_hierarchy_data(identity),
+    )
+
+
+def call_hierarchy_items(
+    identity: SymbolIdentity,
+    indexes: dict[str, FileSymbolIndex],
+) -> list[lsp.CallHierarchyItem]:
+    """Build the hierarchy item for one unambiguous workspace procedure."""
+    item = _call_hierarchy_item(identity, indexes, _proc_definitions(indexes))
+    return [item] if item is not None else []
+
+
+def _range_key(range_: lsp.Range) -> tuple[int, int, int, int]:
+    return (
+        range_.start.line,
+        range_.start.character,
+        range_.end.line,
+        range_.end.character,
+    )
+
+
+def _item_key(item: lsp.CallHierarchyItem) -> tuple[str, str, int, int]:
+    return (
+        item.name.casefold(),
+        item.uri,
+        item.selection_range.start.line,
+        item.selection_range.start.character,
+    )
+
+
+def incoming_call_hierarchy(
+    identity: SymbolIdentity,
+    indexes: dict[str, FileSymbolIndex],
+    definitions: set[SymbolIdentity],
+) -> list[lsp.CallHierarchyIncomingCall]:
+    """Return statically resolved workspace procedures that call ``identity``."""
+    proc_definitions = _proc_definitions(indexes)
+    if _unique_proc_definition(identity, proc_definitions) is None:
+        return []
+
+    grouped: dict[SymbolIdentity, list[lsp.Range]] = {}
+    for _, occurrence in matching_occurrences(identity, indexes, definitions):
+        if occurrence.is_definition or occurrence.caller is None:
+            continue
+        caller = occurrence.caller
+        if caller.kind == "proc" and (
+            _unique_proc_definition(caller, proc_definitions) is None
+        ):
+            continue
+        grouped.setdefault(caller, []).append(occurrence.range)
+
+    results = []
+    for caller, ranges in grouped.items():
+        item = _call_hierarchy_item(caller, indexes, proc_definitions)
+        if item is not None:
+            results.append(
+                lsp.CallHierarchyIncomingCall(
+                    from_=item,
+                    from_ranges=sorted(ranges, key=_range_key),
+                )
+            )
+    return sorted(results, key=lambda call: _item_key(call.from_))
+
+
+def outgoing_call_hierarchy(
+    identity: SymbolIdentity,
+    indexes: dict[str, FileSymbolIndex],
+    definitions: set[SymbolIdentity],
+) -> list[lsp.CallHierarchyOutgoingCall]:
+    """Return statically resolved workspace procedures called by ``identity``."""
+    proc_definitions = _proc_definitions(indexes)
+    if identity.kind == "proc":
+        if _unique_proc_definition(identity, proc_definitions) is None:
+            return []
+    elif identity.kind == "file":
+        if identity.name not in indexes:
+            return []
+    else:
+        return []
+
+    grouped: dict[SymbolIdentity, list[lsp.Range]] = {}
+    for index in indexes.values():
+        for occurrence in index.occurrences:
+            if occurrence.is_definition or occurrence.caller != identity:
+                continue
+            callee = resolve_identity(occurrence, definitions)
+            if _unique_proc_definition(callee, proc_definitions) is None:
+                continue
+            grouped.setdefault(callee, []).append(occurrence.range)
+
+    results = []
+    for callee, ranges in grouped.items():
+        item = _call_hierarchy_item(callee, indexes, proc_definitions)
+        if item is not None:
+            results.append(
+                lsp.CallHierarchyOutgoingCall(
+                    to=item,
+                    from_ranges=sorted(ranges, key=_range_key),
+                )
+            )
+    return sorted(results, key=lambda call: _item_key(call.to))

server/tests/python_tests/test_navigation.py

@@ -1,22 +1,25 @@
 import sys
 from pathlib import Path
 
-
 THIS_DIR = Path(__file__).parent
 SRC_DIR = THIS_DIR.parent.parent / "src"
 if str(SRC_DIR) not in sys.path:
     sys.path.insert(0, str(SRC_DIR))
 
-import lsprotocol.types as lsp  # type: ignore
-from pygls.workspace.text_document import TextDocument
-
 import lsp_server
+import lsprotocol.types as lsp  # type: ignore
 from lsp_tclserver import TclLanguageServer
+from lsprotocol.converters import get_converter
+from pygls.workspace.text_document import TextDocument
 from tools.navigation import (
     SymbolIdentity,
     build_file_symbol_index,
+    call_hierarchy_identity,
+    call_hierarchy_items,
     definition_identities,
+    incoming_call_hierarchy,
     matching_occurrences,
+    outgoing_call_hierarchy,
     symbol_at_position,
     workspace_symbols,
 )
@@ -269,3 +272,132 @@ def test_duplicate_proc_definition_cannot_be_renamed(tmp_path: Path, monkeypatch
     )
 
     assert result is None
+
+
+def test_call_hierarchy_tracks_cross_file_event_calls(tmp_path: Path, monkeypatch):
+    library_source = """proc leaf {} { return }
+namespace eval shop {
+    proc middle {} {
+        ::leaf
+    }
+}
+"""
+    event_source = """proc MOM_linear_move {} {
+    ::shop::middle
+    ::shop::middle
+    puts done
+}
+"""
+    bootstrap_source = "::shop::middle\n"
+    library = _document(tmp_path / "library.tcl", library_source)
+    event = _document(tmp_path / "event.tcl", event_source)
+    bootstrap = _document(tmp_path / "bootstrap.tcl", bootstrap_source)
+    server = TclLanguageServer(
+        name="call-hierarchy-test", version="1", max_workers=1
+    )
+    assert server.update_poco_completion_for_file(library)
+    assert server.update_poco_completion_for_file(event)
+    assert server.update_poco_completion_for_file(bootstrap)
+    monkeypatch.setattr(lsp_server, "LSP_SERVER", server)
+
+    prepared = lsp_server.prepare_call_hierarchy(
+        lsp.CallHierarchyPrepareParams(
+            text_document=lsp.TextDocumentIdentifier(uri=event.uri),
+            position=_position(event_source, "middle"),
+        )
+    )
+
+    assert prepared is not None
+    assert len(prepared) == 1
+    middle = prepared[0]
+    assert middle.name == "shop::middle"
+    assert middle.kind == lsp.SymbolKind.Function
+    assert middle.uri == library.uri
+    assert call_hierarchy_identity(middle) == SymbolIdentity(
+        kind="proc", name="::shop::middle"
+    )
+
+    incoming = lsp_server.incoming_calls(
+        lsp.CallHierarchyIncomingCallsParams(item=middle)
+    )
+    assert len(incoming) == 2
+    event_call = next(
+        call for call in incoming if call.from_.kind == lsp.SymbolKind.Event
+    )
+    file_call = next(
+        call for call in incoming if call.from_.kind == lsp.SymbolKind.File
+    )
+    assert event_call.from_.name == "MOM_linear_move"
+    assert len(event_call.from_ranges) == 2
+    assert file_call.from_.name == "bootstrap.tcl"
+    assert len(file_call.from_ranges) == 1
+    incoming_payload = get_converter().unstructure(event_call)
+    assert incoming_payload["from"]["name"] == "MOM_linear_move"
+    assert len(incoming_payload["fromRanges"]) == 2
+    assert incoming_payload["from"]["data"]["source"] == (
+        "nx-post-support.call-hierarchy"
+    )
+
+    outgoing = lsp_server.outgoing_calls(
+        lsp.CallHierarchyOutgoingCallsParams(item=middle)
+    )
+    assert len(outgoing) == 1
+    assert outgoing[0].to.name == "leaf"
+    assert _range_text(library_source, outgoing[0].from_ranges[0]) == "leaf"
+
+    event_item = event_call.from_
+    event_outgoing = lsp_server.outgoing_calls(
+        lsp.CallHierarchyOutgoingCallsParams(item=event_item)
+    )
+    assert len(event_outgoing) == 1
+    assert event_outgoing[0].to.name == "shop::middle"
+    assert len(event_outgoing[0].from_ranges) == 2
+
+    file_outgoing = lsp_server.outgoing_calls(
+        lsp.CallHierarchyOutgoingCallsParams(item=file_call.from_)
+    )
+    assert len(file_outgoing) == 1
+    assert file_outgoing[0].to.name == "shop::middle"
+    assert len(file_outgoing[0].from_ranges) == 1
+
+
+def test_call_hierarchy_ignores_dynamic_and_ambiguous_calls(tmp_path: Path):
+    caller_source = """proc caller {command} {
+    $command
+    duplicate
+}
+"""
+    caller = _index(tmp_path / "caller.tcl", caller_source)
+    duplicate_a = _index(tmp_path / "duplicate_a.tcl", "proc duplicate {} {}\n")
+    duplicate_b = _index(tmp_path / "duplicate_b.tcl", "proc duplicate {} {}\n")
+    indexes = {
+        caller.path: caller,
+        duplicate_a.path: duplicate_a,
+        duplicate_b.path: duplicate_b,
+    }
+    definitions = definition_identities(indexes)
+    caller_identity = SymbolIdentity(kind="proc", name="::caller")
+    duplicate_identity = SymbolIdentity(kind="proc", name="::duplicate")
+
+    assert call_hierarchy_items(duplicate_identity, indexes) == []
+    assert (
+        incoming_call_hierarchy(duplicate_identity, indexes, definitions) == []
+    )
+    assert outgoing_call_hierarchy(caller_identity, indexes, definitions) == []
+
+
+def test_call_hierarchy_item_uses_whole_proc_range(tmp_path: Path):
+    source = """proc multiline {} {
+    return
+}
+"""
+    index = _index(tmp_path / "range.tcl", source)
+    items = call_hierarchy_items(
+        SymbolIdentity(kind="proc", name="::multiline"),
+        {index.path: index},
+    )
+
+    assert len(items) == 1
+    assert items[0].selection_range.start == lsp.Position(line=0, character=5)
+    assert items[0].range.start == lsp.Position(line=0, character=0)
+    assert items[0].range.end.line == 2