[SCM] PostGIS branch master updated. 3.6.0rc2-164-g59d2f3dc7

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- Log -----------------------------------------------------------------
commit 59d2f3dc7f7bc15f1bb924c71610fbdee61a6ef3
Author: Darafei Praliaskouski <me at komzpa.net>
Date:   Thu Oct 30 03:46:26 2025 +0400

    Guard against histogram axis dimension underflow
    
    References #5959
    References #5984

diff --git a/postgis/cunit/cu_tester.c b/postgis/cunit/cu_tester.c
index b4dd46aa7..eb6ba5b0d 100644
--- a/postgis/cunit/cu_tester.c
+++ b/postgis/cunit/cu_tester.c
@@ -28,6 +28,7 @@
 
 #include <CUnit/Basic.h>
 #include <limits.h>
+#include <math.h>
 #include <string.h>
 
 #include "../gserialized_estimate_support.h"
@@ -82,6 +83,23 @@ histogram_budget_clamps(void)
 	CU_ASSERT_EQUAL(histogram_cell_budget((double)INT_MAX, 50000, INT_MAX), INT_MAX);
 }
 
+static void
+histogram_axis_allocation_guards(void)
+{
+	/* Baseline: evenly split a 10k target over two varying dimensions. */
+	CU_ASSERT_EQUAL(histogram_axis_cells(10000, 2, 0.5), 100);
+
+	/* Skewed axis ratios that collapse to tiny powers still return one cell. */
+	CU_ASSERT_EQUAL(histogram_axis_cells(10000, 2, 1e-9), 1);
+
+	/* Denormals, NaNs and negative ratios should not leak to the histogram. */
+	CU_ASSERT_EQUAL(histogram_axis_cells(10000, 2, NAN), 1);
+	CU_ASSERT_EQUAL(histogram_axis_cells(10000, 2, -0.5), 1);
+
+	/* Extremely aggressive ratios remain bounded by the square root of the budget. */
+	CU_ASSERT_EQUAL(histogram_axis_cells(INT_MAX, 2, 1.0), (int)sqrt((double)INT_MAX * 2.0));
+}
+
 static void
 nd_stats_indexing_behaviour(void)
 {
@@ -138,6 +156,7 @@ main(void)
 		goto cleanup;
 
 	if (!CU_add_test(suite, "histogram budget clamps", histogram_budget_clamps) ||
+	    !CU_add_test(suite, "histogram axis guards", histogram_axis_allocation_guards) ||
 	    !CU_add_test(suite, "nd_stats value index guards", nd_stats_indexing_behaviour) ||
 	    !CU_add_test(suite, "nd_box ratio edge cases", nd_box_ratio_cases))
 	{
diff --git a/postgis/gserialized_estimate.c b/postgis/gserialized_estimate.c
index 5c4b4387b..d616cbeba 100644
--- a/postgis/gserialized_estimate.c
+++ b/postgis/gserialized_estimate.c
@@ -1516,11 +1516,10 @@ compute_gserialized_stats_mode(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfu
 				 * Scale the target cells number by the # of dims and ratio,
 				 * then take the appropriate root to get the estimated number of cells
 				 * on this axis (eg, pow(0.5) for 2d, pow(0.333) for 3d, pow(0.25) for 4d)
-				*/
-				histo_size[d] = (int)pow((double)histo_cells_target * histo_ndims * edge_ratio, 1/(double)histo_ndims);
-				/* If something goes awry, just give this dim one slot */
-				if ( ! histo_size[d] )
-					histo_size[d] = 1;
+				 * The dedicated helper clamps pathological floating point inputs so we
+				 * do not resurrect the NaN propagation reported in #5959 on amd64.
+				 */
+				histo_size[d] = histogram_axis_cells(histo_cells_target, histo_ndims, edge_ratio);
 			}
 			histo_cells_new *= histo_size[d];
 		}
diff --git a/postgis/gserialized_estimate_support.h b/postgis/gserialized_estimate_support.h
index 0d3a23d75..6b372a43e 100644
--- a/postgis/gserialized_estimate_support.h
+++ b/postgis/gserialized_estimate_support.h
@@ -151,6 +151,46 @@ histogram_cell_budget(double total_rows, int ndims, int attstattarget)
 	return (int)budget;
 }
 
+/*
+ * Allocate histogram buckets along a single axis in proportion to the observed
+ * density variation.  The caller passes in the global histogram target along
+ * with the number of axes that exhibited variation in the sampled data and the
+ * relative contribution of the current axis (edge_ratio).  Earlier versions
+ * evaluated the pow() call directly in the caller, which exposed the planner to
+ * NaN propagation on some amd64 builds when the ratio was denormal or negative
+ * (see #5959).  Keeping the calculation in one place allows us to clamp the
+ * inputs and provide a predictable fallback for problematic floating point
+ * combinations.
+ */
+static inline int
+histogram_axis_cells(int histo_cells_target, int histo_ndims, double edge_ratio)
+{
+	double scaled;
+	double axis_cells;
+
+	if (histo_cells_target <= 0 || histo_ndims <= 0)
+		return 1;
+
+	if (!(edge_ratio > 0.0) || !isfinite(edge_ratio))
+		return 1;
+
+	scaled = (double)histo_cells_target * (double)histo_ndims * edge_ratio;
+	if (!(scaled > 0.0) || !isfinite(scaled))
+		return 1;
+
+	axis_cells = pow(scaled, 1.0 / (double)histo_ndims);
+	if (!(axis_cells > 0.0) || !isfinite(axis_cells))
+		return 1;
+
+	if (axis_cells >= (double)INT_MAX)
+		return INT_MAX;
+
+	if (axis_cells <= 1.0)
+		return 1;
+
+	return (int)axis_cells;
+}
+
 /*
  * Compute the portion of 'target' covered by 'cover'.  The caller supplies the
  * dimensionality because ND_BOX always carries four slots.  Degenerate volumes

-----------------------------------------------------------------------

Summary of changes:
 postgis/cunit/cu_tester.c              | 19 ++++++++++++++++
 postgis/gserialized_estimate.c         |  9 ++++----
 postgis/gserialized_estimate_support.h | 40 ++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 5 deletions(-)


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