fix(lib,scheduler): allocation constructors and allocators report OOM instead of building NULL-name records (bug-1882)

make_alloc() and make_host_alloc() assigned strdup() results unchecked,
so under memory exhaustion they returned a record whose resname/reserve/
host was NULL; merge_job_alloc()'s same_alloc_slot() (bug-1863) then
strcmp()'d it (ASAN SEGV at xcealloc.c:337). make_alloc() also passed a
NULL resname straight to strdup().
- xcealloc.c: make_alloc()/make_host_alloc() reject a NULL name (EINVAL)
  and check every strdup(), freeing what they built and returning NULL
  (ENOMEM); on failure make_host_alloc()'s caller keeps `allocs`.
  dup_host_alloc() frees its partial copy on failure instead of leaking.
- scheduler.c sched_make_allocs(): a record that cannot be built fails
  the whole array (NULL, ENOMEM) instead of leaving a NULL entry.
- seqjob/parjob my_alloc(): check every constructor; on failure free
  what was built (parjob also rolls back the remaining claims) and
  return -ENOMEM with ctx->alloc NULL -- the caller moves ctx.alloc onto
  the job whatever the rc.

Tests: new xcealloc_oom_test (8, --wrap=strdup) and
sched_make_allocs_oom_test (real scheduler_srcs + --wrap=strdup); a new
-ENOMEM test in the seqjob and parjob allocator suites. All RED before
(SEGV / "Expected NULL" / "Expected -12 Was 1"), GREEN after.
xce-build.sh all asan: 115/115 suites OK, Go tests OK.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/scheduler/testsuite/meson.build

@@ -1917,6 +1917,29 @@ test('scheduler repl resource formatting test',
 test('scheduler connect pipeline test',
      sched_scheduler_connect_test, suite: 'scheduler',
      env: ['ASAN_OPTIONS=detect_leaks=0'])
+
+# bug-1882 regression: sched_make_allocs() must fail the whole array when
+# make_alloc() cannot build a record. Real scheduler_srcs (as
+# sched_scheduler_connect_test) plus `-Wl,--wrap=strdup` to make a chosen
+# strdup() inside make_alloc() fail.
+sched_make_allocs_oom_test_srcs = ['test_sched_make_allocs_oom.c']
+foreach f : scheduler_srcs
+  if f != 'src/main.c'
+    sched_make_allocs_oom_test_srcs += ['../' + f]
+  endif
+endforeach
+
+sched_make_allocs_oom_test = executable(
+    'sched_make_allocs_oom_test',
+    sched_make_allocs_oom_test_srcs,
+    include_directories:[incdir],
+    dependencies: [scheduler_deps, unity_dep],
+    link_args: ['-Wl,--wrap=strdup'],
+    install: false)
+
+test('scheduler make_allocs OOM test',
+     sched_make_allocs_oom_test, suite: 'scheduler',
+     env: ['ASAN_OPTIONS=detect_leaks=0'])
 test('scheduler decision publish retry test',
      sched_scheduler_decision_publish_retry_test, suite: 'scheduler',
      env: ['ASAN_OPTIONS=detect_leaks=0'])