What causes "{eventNode} event does not have a symbol" in dotnet/runtime?

Find the element in the manifest that lacks a 'symbol' attribute (the error shows the DOM element repr which includes line information).

dotnet/runtime · error · Exception

event does not have a symbol

Error message

{eventNode} event does not have a symbol

What it means

Raised by generateLttngHeader() in genLttngProvider.py when iterating over event nodes and an event element lacks a 'symbol' attribute. The symbol attribute names the event and is used to generate the TRACEPOINT_EVENT_INSTANCE macro call. Without it, the generated C code would be invalid.

Solutions

Find the <event> element in the manifest that lacks a 'symbol' attribute (the error shows the DOM element repr which includes line information).
Add a unique symbol attribute to the event element, e.g., symbol="MyNewEvent".
Ensure every <event> element has a non-empty symbol matching the naming convention used by other events.

Example fix

<!-- before: event without symbol -->
<event value="99" level="win:Informational" template="t:MyEvent" />

<!-- after: add symbol attribute -->
<event symbol="MyNewEvent" value="99" level="win:Informational" template="t:MyEvent" />

Defensive patterns

Strategy: validation

Validate before calling

import xml.dom.minidom as DOM

def validate_event_symbols(manifest_path: str) -> list:
    """Return list of event elements missing a symbol attribute."""
    tree = DOM.parse(manifest_path)
    missing = []
    for i, event in enumerate(tree.getElementsByTagName('event')):
        symbol = event.getAttribute('symbol')
        if not symbol:
            missing.append(f"Event #{i} (value={event.getAttribute('value')}) has no symbol attribute")
    return missing

Type guard

null

Try / catch

try:
    generateLttngHeader(providerName, allTemplates, eventNodes, runtimeFlavor)
except Exception as e:
    if 'does not have a symbol' in str(e):
        print(f"Manifest error: an <event> element is missing its 'symbol' attribute.")
        print("Add symbol=\"EventName\" to every <event> element in the manifest.")
    raise

Prevention

Always include a non-empty 'symbol' attribute on every <event> element.
Add an XML schema check for required attributes before code generation.
Use consistent naming conventions for event symbols.
Validate the manifest with an XML linter that checks for required attributes.

When it happens

Trigger: Triggered at line 282-283 when eventNode.getAttribute('symbol') returns an empty/falsy string. The code checks 'if not eventName' and raises with eventNode (the DOM element) as the message prefix. Note: the message formats eventNode directly, which will show the XML element's repr, not a human-readable name — a minor diagnostic weakness.

Common situations: A developer adds an <event> element to the manifest but forgets the symbol attribute. The symbol attribute is present but empty (symbol=""). An XML editing error or merge conflict drops the attribute.

Related errors

AI-assisted analysis of dotnet/runtime@60108ba66e (2026-08-10). Data as JSON: /api/errors/cef897c01a15541b. Report an issue: GitHub.

Appendix: source

Thrown at src/coreclr/scripts/genLttngProvider.py:283

#define T_TRACEPOINT_INSTANCE(name) \\
TRACEPOINT_EVENT_INSTANCE(\\
""")
    lTTngHdr.append("    " + providerName + ",\\\n")
    lTTngHdr.append("    emptyTemplate,\\\n")

    lTTngHdr.append("""    name ,\\
    TP_ARGS()\\
)""")
#end of empty template
# create the event instance in headers
    lTTngHdr.append("\n")

    for eventNode in eventNodes:
        eventName    = eventNode.getAttribute('symbol');
        templateName = eventNode.getAttribute('template');

        if not eventName :
            raise Exception(eventNode + " event does not have a symbol")
        if not templateName:
            lTTngHdr.append("T_TRACEPOINT_INSTANCE(")
            lTTngHdr.append(eventName +")\n")
            continue

        subevent = templateName.replace(templateName,'')
        lTTngHdr.append(templateName)
        lTTngHdr.append("T_TRACEPOINT_INSTANCE(")
        lTTngHdr.append(eventName + subevent + ")\n")

    lTTngHdr.append("\n#endif /* LTTNG_CORECLR_H")
    lTTngHdr.append(providerName + " */\n")
    lTTngHdr.append("#include <lttng/tracepoint-event.h>")

    return ''.join(lTTngHdr)


def generateMethodBody(template, providerName, eventName, runtimeFlavor):

View on GitHub (pinned to 60108ba66e)