@@ -1,74 +1,38 @@
 /*
- * repro_issue363.c — Reproduce-first case for OPEN bug #363.
+ * repro_issue363.c — Regression guard for bug #363 (both axes now FIXED).
  *
  * Issue: #363 — "Linux: cbm_system_info / cbm_default_worker_count don't
  *               respect cgroup CPU/memory limits"
  *
- * ROOT CAUSE (two distinct axes):
+ * Both axes of #363 have shipped; this case is now a permanent GREEN guard:
  *
  *   CPU axis — FIXED in v0.8.0 (commit a5a3d1d).
  *     cbm_detect_cgroup_cpus() reads /sys/fs/cgroup/cpu.max (v2) or
- *     .../cpu/cpu.cfs_quota_us + .../cpu/cpu.cfs_period_us (v1) and the
- *     result is used by detect_system_linux() in system_info.c:226.
- *     cbm_default_worker_count() also honours the CBM_WORKERS env override
- *     (commit d952238).  Both are thoroughly tested in test_platform.c.
+ *     .../cpu/cpu.cfs_quota_us + .../cpu/cpu.cfs_period_us (v1); the result
+ *     feeds detect_system_linux(). cbm_default_worker_count() also honours the
+ *     CBM_WORKERS env override (commit d952238). Both tested in test_platform.c.
  *
- *   Memory axis — STILL OPEN (confirmed by reporter @mayurpise in the last
- *     open comment on #363, 2026-06-25).
- *     cbm_detect_cgroup_mem() similarly reads /sys/fs/cgroup/memory.max (v2)
- *     or .../memory/memory.limit_in_bytes (v1), and detect_system_linux()
- *     uses it (system_info.c:229).  BUT: there is NO env-override knob on
- *     the memory axis.  The CPU axis has CBM_WORKERS; the memory side has
- *     nothing.  On a bare-metal host with no enclosing cgroup, users cannot
- *     cap cbm_mem_init's budget without wrapping the process in a cgroup
- *     scope (as @mayurpise's workaround shows).
+ *   Memory axis — FIXED.
+ *     cbm_detect_cgroup_mem() reads /sys/fs/cgroup/memory.max (v2) or
+ *     .../memory/memory.limit_in_bytes (v1); detect_system_linux() applies
+ *     min(cgroup, host). The missing env knob — the "EXACT OPEN GAP" this
+ *     repro was filed for — now exists: cbm_mem_init() reads CBM_MEM_BUDGET_MB
+ *     and routes it through the pure cbm_mem_resolve_budget() (explicit
+ *     override > implicit detection, mirroring CBM_WORKERS).
  *
- * EXACT OPEN GAP:
- *   A CBM_MEM_BUDGET_MB environment variable (analogous to CBM_WORKERS) that
- *   cbm_mem_init() checks before computing g_budget from info.total_ram.
- *   If set to a valid integer N, cbm_mem_init() should set
- *   g_budget = N * 1024 * 1024, honouring it regardless of cgroup or host RAM.
- *
- * WHY THIS TEST IS RED:
- *   cbm_mem_init() (src/foundation/mem.c) reads cbm_system_info().total_ram
- *   and multiplies by ram_fraction.  It does NOT call cbm_safe_getenv for
- *   CBM_MEM_BUDGET_MB — the override path does not exist.  Setting
- *   CBM_MEM_BUDGET_MB=4096 has no effect; cbm_mem_budget() returns a value
- *   derived from host RAM (or cgroup RAM when inside a container), not from
- *   the env var.  The assertion ASSERT_EQ(cbm_mem_budget(), 4096*1024*1024)
- *   therefore fails on any host whose cgroup or physical RAM != exactly 4 GiB.
- *
- * ROOT CAUSE LOCATION:
- *   src/foundation/mem.c, cbm_mem_init(), after the mimalloc option block
- *   (currently around line 126):
- *     cbm_system_info_t info = cbm_system_info();
- *     g_budget = (size_t)((double)info.total_ram * ram_fraction);
- *   The fix is to insert a cbm_safe_getenv("CBM_MEM_BUDGET_MB", ...) lookup
- *   BEFORE this line and, if valid, set g_budget directly without involving
- *   info.total_ram — mirroring the CBM_WORKERS pattern in
- *   cbm_default_worker_count() (system_info.c:290).
- *
- * INTENDED FIX:
- *   1. In cbm_mem_init(): read CBM_MEM_BUDGET_MB; if set to a valid positive
- *      integer, use that value (in bytes) as g_budget and log it.
- *   2. Test: set CBM_MEM_BUDGET_MB=4096, call cbm_mem_init(0.5), assert
- *      cbm_mem_budget() == 4096 * 1024 * 1024.  This test goes GREEN when
- *      the override is wired.
- *   3. Complementary: on Linux, confirm cbm_system_info().total_ram is capped
- *      by the cgroup memory limit when present — already covered in
- *      test_platform.c via cbm_detect_cgroup_mem() unit tests, but an
- *      integration path via cbm_system_info() is untestable without a seam
- *      that lets callers override the hardcoded "/sys/fs/cgroup" root in
- *      detect_system_linux() (system_info.c:229).
+ * IMPORTANT — clamp semantics:
+ *   cbm_mem_resolve_budget() clamps the override to effective (cgroup/host) RAM
+ *   so it can never claim more than the box has. So a *large* override is NOT
+ *   honoured verbatim on a small host — it clamps to total_ram. This guard
+ *   therefore uses a small budget (REPRO363_BUDGET_MB) that is at/below any
+ *   realistic host's RAM, so it is honoured exactly and the assertion is stable
+ *   on every runner. The clamp behaviour itself is unit-tested separately in
+ *   tests/test_mem.c (resolve_budget_override_clamped_to_total).
  *
  * NOTE on cbm_mem_init() caching:
- *   g_budget is initialised once via atomic_compare_exchange_strong.
- *   The test must run in a process where cbm_mem_init() has NOT been called
- *   yet, OR the test must reset g_initialized — neither is supported today.
- *   The repro works as written because the repro runner does not call
- *   cbm_mem_init() before this suite.  If the initialisation guard is an
- *   issue, the fix also needs a cbm_mem_reset_for_test() hook (test-only,
- *   guarded by CBM_TEST_HOOKS or similar).
+ *   g_budget is initialised once via atomic_compare_exchange_strong, so this
+ *   guard relies on running before any suite that calls cbm_mem_init(); the
+ *   repro runner does not init the budget before this suite.
  */
 
 #include "test_framework.h"
@@ -77,39 +41,27 @@
 #include <stdint.h>
 #include <stdlib.h>
 
-#define REPRO363_BUDGET_MB 4096UL
+/* Deliberately small so the resolver honours it exactly (never clamps) on any
+ * host — see the clamp-semantics note above. */
+#define REPRO363_BUDGET_MB 128UL
 #define REPRO363_BUDGET_BYTES (REPRO363_BUDGET_MB * 1024UL * 1024UL)
 
 /*
  * repro_issue363_mem_budget_env_override
  *
- * Precondition: CBM_MEM_BUDGET_MB=4096 is set before cbm_mem_init() is
- * called.  The budget should be 4096 MiB regardless of host RAM or cgroup.
- *
- * RED condition (current code):
- *   cbm_mem_init() ignores CBM_MEM_BUDGET_MB entirely; cbm_mem_budget()
- *   returns host-RAM * fraction, not 4 GiB.  The assertion fires unless the
- *   test runner happens to be on a machine whose effective RAM is exactly
- *   8 GiB with fraction=0.5 — essentially never.
- *
- * GREEN condition (after fix):
- *   cbm_mem_init() reads CBM_MEM_BUDGET_MB, finds "4096", sets
- *   g_budget = 4096 * 1024 * 1024.  The assertion passes on any machine.
+ * Precondition: CBM_MEM_BUDGET_MB is set before the process's first
+ * cbm_mem_init(). The budget must equal the override (honoured exactly, since
+ * it is below any host's effective RAM), proving the env knob is wired.
  */
 TEST(repro_issue363_mem_budget_env_override) {
-    cbm_setenv("CBM_MEM_BUDGET_MB", "4096", 1);
+    cbm_setenv("CBM_MEM_BUDGET_MB", "128", 1);
 
     cbm_mem_init(0.5);
 
     size_t budget = cbm_mem_budget();
 
     cbm_unsetenv("CBM_MEM_BUDGET_MB");
 
-    /*
-     * RED on current code: budget derives from host/cgroup RAM, not the env
-     * var.  On any machine where effective RAM != 8192 MiB this fails.
-     * GREEN once CBM_MEM_BUDGET_MB is wired in cbm_mem_init().
-     */
     ASSERT_EQ((long long)budget, (long long)REPRO363_BUDGET_BYTES);
 
     PASS();