What causes "--ucadata was used with UCONFIG_NO_COLLATION" in nodejs/node?

Rebuild ICU without UCONFIG_NO_COLLATION so collation support is available.

--ucadata was used with UCONFIG_NO_COLLATION

Error message

--ucadata was used with UCONFIG_NO_COLLATION

What it means

The --ucadata flag triggers CollationRoot::forceLoadFromFile(), which needs the collation framework. When ICU was compiled with UCONFIG_NO_COLLATION defined, collation is compiled out entirely, so loading ucadata is impossible. The #else branch at genrb.cpp:317-319 prints this message and returns the current status. This is a compile-time configuration mismatch, not a runtime data problem.

Source

Thrown at deps/icu-small/source/tools/genrb/genrb.cpp:318

    }
    status = U_ZERO_ERROR;
    if(options[WRITE_JAVA].doesOccur) {
        write_java = true;
        outputEnc = options[WRITE_JAVA].value;
    }

    if(options[WRITE_XLIFF].doesOccur) {
        write_xliff = true;
        if(options[WRITE_XLIFF].value != nullptr){
            xliffOutputFileName = options[WRITE_XLIFF].value;
        }
    }

    if (options[UCADATA].doesOccur) {
#if !UCONFIG_NO_COLLATION
        CollationRoot::forceLoadFromFile(options[UCADATA].value, status);
#else
        fprintf(stderr, "--ucadata was used with UCONFIG_NO_COLLATION\n");
        return status;
#endif
    }

    initParser();

    /*added by Jing*/
    if(options[LANGUAGE].doesOccur) {
        language = options[LANGUAGE].value;
    }

    LocalPointer<SRBRoot> newPoolBundle;
    if(options[WRITE_POOL_BUNDLE].doesOccur) {
        newPoolBundle.adoptInsteadAndCheckErrorCode(new SRBRoot(nullptr, true, status), status);
        if(U_FAILURE(status)) {
            fprintf(stderr, "unable to create an empty bundle for the pool keys: %s\n", u_errorName(status));
            return status;
        } else {

View on GitHub (pinned to 1b2de5e052)

Solutions

Rebuild ICU without UCONFIG_NO_COLLATION so collation support is available.
Drop --ucadata from the genrb invocation if you genuinely do not need collation data.
Align the build configuration of the genrb binary with the data set you are compiling.

Defensive patterns

Strategy: validation

Validate before calling

# If --ucadata is requested, ensure the genrb binary was built with collation
if [ -n "$UCADATA_FILE" ]; then
  if pkg-config --exists icu-i18n 2>/dev/null && ! pkg-config --cflags icu-i18n | grep -q UCONFIG_NO_COLLATION; then
    : # ok
  else
    echo "WARNING: ICU built without collation; --ucadata will fail" >&2
  fi
fi

Prevention

Keep the build configuration of the genrb tool in lock-step with the feature set the data tree expects.
When stripping ICU features for size, also strip the corresponding data-build flags.

When it happens

Trigger: Building ICU with -DUCONFIG_NO_COLLATION=1 (common on minimal/embedded builds) and then running a genrb invocation that passes --ucadata <file>.

Common situations: A stripped-down ICU build for a constrained target where collation was disabled to save space, then reusing that toolchain to compile locale data that still references ucadata; mixing a minimal ICU tool build with a full data tree.

Related errors

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/63d39b803b5a8eb2. Report an issue: GitHub.