unable to create an empty bundle for the pool keys: %s

Error message

unable to create an empty bundle for the pool keys: %s

What it means

While initializing a fresh pool bundle (the keys-only bundle written by --writePoolBundle), genrb constructs `new SRBRoot(nullptr, true, status)`. If that constructor reports a failure via the UErrorCode (typically U_MEMORY_ALLOCATION_ERROR), the message prints the human-readable code via u_errorName and returns it. The pool bundle is the shared key table that other .res files reference to reduce size.

Source

Thrown at deps/icu-small/source/tools/genrb/genrb.cpp:334

        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 {
            const char *poolResName = "pool.res";
            char *nameWithoutSuffix = static_cast<char *>(uprv_malloc(uprv_strlen(poolResName) + 1));
            if (nameWithoutSuffix == nullptr) {
                fprintf(stderr, "out of memory error\n");
                return U_MEMORY_ALLOCATION_ERROR;
            }
            uprv_strcpy(nameWithoutSuffix, poolResName);
            *uprv_strrchr(nameWithoutSuffix, '.') = 0;
            newPoolBundle->fLocale = nameWithoutSuffix;
        }
    }

    if(options[USE_POOL_BUNDLE].doesOccur) {
        const char *poolResName = "pool.res";
        FileStream *poolFile;
        int32_t poolFileSize;

View on GitHub (pinned to 1b2de5e052)

Solutions

Free memory or raise the container's memory limit before re-running.
Reduce parallelism in the data build so each genrb process has enough headroom.
Inspect the status string printed (e.g. U_MEMORY_ALLOCATION_ERROR) to confirm it is a memory problem rather than a logic error.

Defensive patterns

Strategy: try-catch

Validate before calling

# Best-effort preflight: ensure enough free memory for the build
min_mb=512
free_mb=$(awk '/MemAvailable/ {print int($2/1024)}' /proc/meminfo 2>/dev/null || echo 0)
if [ "$free_mb" -lt "$min_mb" ]; then
  echo "WARNING: only ${free_mb}MB free; pool bundle init may fail" >&2
fi

Try / catch

genrb --writePoolBundle "$OUT_DIR" "$@" 2>err.log
if grep -q 'unable to create an empty bundle' err.log; then
  echo "Pool bundle init failed; freeing memory or reducing parallelism" >&2; exit 1
fi

Prevention

Cap genrb parallelism in your build system to keep heap usage bounded.
Monitor RSS of build workers so OOM conditions surface before they hit genrb.

When it happens

Trigger: Running `genrb --writePoolBundle out/ *.txt` on a system under severe memory pressure, or with a corrupted/oversized input that causes the SRBRoot constructor to fail its internal allocations.

Common situations: Building ICU data inside a memory-limited container or CI runner; running many parallel genrb processes that exhaust RAM.

Related errors

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/53cf04e53f75c4a8. Report an issue: GitHub.