src: assert memory calc for max-old-space-size-percentage

Add validation to ensure that --max-old-space-size-percentage cannot
be used when available memory cannot be calculated, preventing
undefined behavior when memory detection fails.
Also enhance test-process-constrained-memory.js to support testing
in constrained environments where memory calculation may fail.
PR-URL: #59460
Backport-PR-URL: #59631
Reviewed-By: theanarkh <theratliter@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>

Author: Asaf-Federman

src/node_options.cc

@@ -134,6 +134,11 @@ void PerIsolateOptions::HandleMaxOldSpaceSizePercentage(
  ? constrained_memory
  : total_memory;
 
+if (available_memory == 0) {
+ errors->push_back("the available memory can not be calculated");
+return;
+ }
+
 // Convert to MB and calculate the percentage
 uint64_t memory_mb = available_memory / (1024 * 1024);
 uint64_t calculated_mb = static_cast<size_t>(memory_mb * percentage / 100.0);

test/parallel/test-max-old-space-size-percentage.js

@@ -119,14 +119,19 @@ assert(
 
 // Validate heap sizes against system memory
 consttotalMemoryMB=Math.floor(os.totalmem()/1024/1024);
-constmargin=10;// 5% margin
+constuint64Max=2**64-1;
+constconstrainedMemory=process.constrainedMemory();
+constconstrainedMemoryMB=Math.floor(constrainedMemory/1024/1024);
+consteffectiveMemoryMB=
+constrainedMemory>0&&constrainedMemory!==uint64Max ? constrainedMemoryMB : totalMemoryMB;
+constmargin=10;// 10% margin
 testPercentages.forEach((percentage)=>{
-constupperLimit=totalMemoryMB*((percentage+margin)/100);
+constupperLimit=effectiveMemoryMB*((percentage+margin)/100);
 assert(
 heapSizes[percentage]<=upperLimit,
 `Heap size for ${percentage}% (${heapSizes[percentage]} MB) should not exceed upper limit (${upperLimit} MB)`
 );
-constlowerLimit=totalMemoryMB*((percentage-margin)/100);
+constlowerLimit=effectiveMemoryMB*((percentage-margin)/100);
 assert(
 heapSizes[percentage]>=lowerLimit,
 `Heap size for ${percentage}% (${heapSizes[percentage]} MB) should not be less than lower limit (${lowerLimit} MB)`