quarkusio/quarkus · error · CodestartStructureException

ConflictStrategyHandler named '" + entry.getValue() + "' not

Error message

ConflictStrategyHandler named '" + entry.getValue() + "' not found. Used with filter '" + entry.getKey() + "'

What it means

CodestartProcessor.buildStrategies maps codestart conflict-strategy spec entries to named CodestartFileStrategyHandler instances via a BY_NAME registry. This error means a strategy name in the codestart spec (codestarts.yml / project generation config) does not match any registered handler. It is a configuration error in the codestart definition, not user code.

Source

Thrown at independent-projects/tools/codestarts/src/main/java/io/quarkus/devtools/codestarts/core/CodestartProcessor.java:94

        }
    }

    public void writeFiles() throws IOException {
        for (Map.Entry<String, List<TargetFile>> e : files.entrySet()) {
            final String relativePath = e.getKey();
            final CodestartFileStrategyHandler strategy = getStrategy(relativePath).orElse(getSelectedDefaultStrategy());
            log.debug("processing file '%s' with strategy %s", relativePath, strategy.name());
            strategy.process(targetDirectory, relativePath, e.getValue(), data);
        }
    }

    public static List<CodestartFileStrategy> buildStrategies(Map<String, String> spec) {
        final List<CodestartFileStrategy> codestartFileStrategyHandlers = new ArrayList<>(spec.size());

        for (Map.Entry<String, String> entry : spec.entrySet()) {
            final CodestartFileStrategyHandler handler = CodestartFileStrategyHandler.BY_NAME.get(entry.getValue());
            if (handler == null) {
                throw new CodestartStructureException("ConflictStrategyHandler named '" + entry.getValue()
                        + "' not found. Used with filter '" + entry.getKey() + "'");
            }
            codestartFileStrategyHandlers.add(new CodestartFileStrategy(entry.getKey(), handler));
        }
        return codestartFileStrategyHandlers;
    }

    void addBuiltinData() {
        // needed for azure functions codestart
        data.put("gen-info", Collections.singletonMap("time", System.currentTimeMillis()));
    }

    void processLanguageDir(final CodestartResource projectResource, final CodestartResource resource, final String languageDir,
            final Map<String, Object> finalData) {
        log.debug("processing dir: %s", resource.pathName());
        final List<Source> sources = resource.listSources(languageDir);

        for (Source source : sources) {

View on GitHub (pinned to e1c734241f)

Solutions

1. Fix the strategy name in the codestart spec to one of the registered handler names (e.g. default, override, merge, fail) — check CodestartFileStrategyHandler for valid values
2. Update the custom codestart definition to match the current Quarkus codestart spec
3. If a custom handler was intended, register/define it in the handlers enum before use

Example fix

# before
codestart:
  conflict-strategy:
    '*': overwrit
# after
codestart:
  conflict-strategy:
    '*': override

spec.values().forEach(v -> {
    if (!CodestartFileStrategyHandler.BY_NAME.containsKey(v))
        throw new IllegalArgumentException("Unknown strategy handler: " + v);
});

try {
    CodestartProcessor.buildStrategies(spec);
} catch (CodestartStructureException e) {
    // surface the offending filter/strategy name from e.getMessage()
}

When it happens

Trigger: A codestart YAML declares a 'conflict-strategy' (or file strategy) map whose value names a handler that is not in CodestartFileStrategyHandler.BY_NAME, and a project generation loads that codestart.

Common situations: Typos in strategy names in codestarts.yml; renaming/removing a handler enum constant while old codestarts still reference it; custom codestarts copied from an incompatible Quarkus version.

Related errors

• can't be used as '*' file strategy
• Failed to load codestart spec: + resourceName
• Multiple fallback found for a base codestart of type: '" + a
• Invalid CodestartDep expression: + expression
• Expected a value of type ${type.getName()} for option ${name

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/b0ea7c8c68e212bc. Report an issue: GitHub.