Fix config rewrite producing negative values for unsigned memory configs

[enjoy-binbin]

rewriteConfigFormatMemory() and rewriteConfigBytesOption() used long long
parameters to represent memory bytes, but configs like maxmemory are stored
as unsigned long long and allow values up to ULLONG_MAX.

When the value exceeds LLONG_MAX (e.g. 9223372036854775808), it overflows to
negative when passed as long long, causing config rewrite to produce incorrect
output like "maxmemory -8589934592gb".

Change both functions to use unsigned long long, matching the actual semantics
of memory byte values. This is consistent with how numericConfigGet() already
handles MEMORY_CONFIG using ull2string().

There are some MEMORY_CONFIG are signed and can be negative:

1. maxmemory-clients is a PERCENT_CONFIG
2. slot-migration-max-failover-repl-bytes is a SIGNED_MEMORY_CONFIG (after Fix slot-migration-max-failover-repl-bytes unable to accept -1 #3443)

None of them were affected:

static void numericConfigRewrite(standardConfig *config, const char *name, struct rewriteConfigState *state) {
    ...
    if (config->data.numeric.flags & PERCENT_CONFIG && value < 0) {
        rewriteConfigPercentOption(state, name, -value, config->data.numeric.default_value);
    } else if (config->data.numeric.flags & SIGNED_MEMORY_CONFIG && value < 0) {
        rewriteConfigNumericalOption(state, name, value, config->data.numeric.default_value);
    } else if (config->data.numeric.flags & MEMORY_CONFIG) {
        rewriteConfigBytesOption(state, name, value, config->data.numeric.default_value);
    ...

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.49%. Comparing base (dba128f) to head (ee075c1).
⚠️ Report is 4 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #3440      +/-   ##
============================================
- Coverage     76.52%   76.49%   -0.03%     
============================================
  Files           157      157              
  Lines         79035    79035              
============================================
- Hits          60478    60455      -23     
- Misses        18557    18580      +23     

Files with missing lines	Coverage Δ
src/config.c	78.33% <100.00%> (+0.31%)	⬆️

... and 25 files with indirect coverage changes

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[zuiderkwast]

Some MEMORY_CONFIG are signed and can be negative:

src/config.c:    createSSizeTConfig("maxmemory-clients", NULL, MODIFIABLE_CONFIG, -100, SSIZE_MAX, server.maxmemory_clients, 0, MEMORY_CONFIG | PERCENT_CONFIG, NULL, applyClientMaxMemoryUsage),
src/config.c:    createSSizeTConfig("slot-migration-max-failover-repl-bytes", NULL, MODIFIABLE_CONFIG, -1, SSIZE_MAX, server.slot_migration_max_failover_repl_bytes, 0, MEMORY_CONFIG, NULL, NULL),

[enjoy-binbin]

Some MEMORY_CONFIG are signed and can be negative:

@zuiderkwast Yes, but it does not affect since we will rewrite PERCENT_CONFIG first, see

static void numericConfigRewrite(standardConfig *config, const char *name, struct rewriteConfigState *state) {
    long long value = 0;

    GET_NUMERIC_TYPE(value)

    if (config->data.numeric.flags & PERCENT_CONFIG && value < 0) {
        rewriteConfigPercentOption(state, name, -value, config->data.numeric.default_value);
    } else if (config->data.numeric.flags & MEMORY_CONFIG) {
        rewriteConfigBytesOption(state, name, value, config->data.numeric.default_value);
    }
    ...
}

[zuiderkwast]

Some MEMORY_CONFIG are signed and can be negative:

@zuiderkwast Yes, but it does not affect since we will rewrite PERCENT_CONFIG first,

But slot-migration-max-failover-repl-bytes is not a percent config.

[enjoy-binbin]

But slot-migration-max-failover-repl-bytes is not a percent config.

@zuiderkwast So after #3443, does this slove you concern?

[enjoy-binbin]

The other issue is:

127.0.0.1:6379> config set maxmemory 9223372036854775808
OK
127.0.0.1:6379> config set maxmemory-clients 100%
OK
127.0.0.1:6379> config set maxmemory-clients 9223372036854775808
(error) ERR CONFIG SET failed (possibly related to argument 'maxmemory-clients') - percentage argument must be less or equal to 100

I think we can leave it as it is for now.