filer: keep S3 list order byte-lexicographic regardless of SQL name column collation (#9824)

* mysql: keep S3 list order byte-lexicographic regardless of name column collation

ORDER BY name and the name > ? pagination predicate follow the column
collation, so a case-insensitive filemeta.name (e.g. utf8mb3_general_ci)
returns S3 keys out of byte order and breaks clients that merge two sorted
listings.

Detect the live name collation at startup; only when it isn't binary, wrap
the list comparison, prefix, and ORDER BY in BINARY name so order and
pagination stay consistent. Correctly configured utf8mb4_bin tables keep
their indexed range scan unchanged, and the operator gets a warning to
convert the column.

* postgres: keep S3 list order byte-lexicographic regardless of name column collation

ORDER BY name and the name > $n pagination predicate follow the column or
database collation, so a locale-aware filemeta.name (e.g. the en_US.UTF-8
database default) returns S3 keys out of byte order and breaks clients that
merge two sorted listings.

Detect the live name collation at startup; only when it isn't byte-ordered,
wrap the list comparison, prefix, and ORDER BY in COLLATE "C" so order and
pagination stay consistent. A byte-ordered (C/POSIX/C.UTF-8) column keeps its
indexed range scan unchanged, and the operator gets a warning to declare the
column COLLATE "C".

weed/filer/postgres/postgres_sql_gen_test.go

@@ -23,3 +23,45 @@ func TestEmptyUpsertTemplateFallsBackToPlainInsert(t *testing.T) {
 		t.Fatalf("plain INSERT path should not contain ON CONFLICT, got: %s", got)
 	}
 }
+
+func TestListSqlDefaultOrderingFollowsColumn(t *testing.T) {
+	gen := &SqlGenPostgres{}
+	for _, got := range []string{gen.GetSqlListExclusive("filemeta"), gen.GetSqlListInclusive("filemeta")} {
+		if strings.Contains(got, "COLLATE") {
+			t.Fatalf("default list query should not force a collation, got: %s", got)
+		}
+		if !strings.Contains(got, "ORDER BY name ASC") {
+			t.Fatalf("expected plain name ordering, got: %s", got)
+		}
+	}
+}
+
+func TestListSqlBinaryOrderingOnNonBinaryColumn(t *testing.T) {
+	gen := &SqlGenPostgres{ForceBinaryCollation: true}
+	for _, got := range []string{gen.GetSqlListExclusive("filemeta"), gen.GetSqlListInclusive("filemeta")} {
+		if !strings.Contains(got, `ORDER BY name COLLATE "C" ASC`) {
+			t.Fatalf(`expected COLLATE "C" ordering, got: %s`, got)
+		}
+		if !strings.Contains(got, `name COLLATE "C" like $4`) {
+			t.Fatalf(`expected COLLATE "C" prefix filter, got: %s`, got)
+		}
+		if strings.Contains(got, "AND name>$2") || strings.Contains(got, "AND name>=$2") {
+			t.Fatalf("pagination comparison must also be byte-ordered, got: %s", got)
+		}
+	}
+}
+
+func TestIsByteOrderedCollation(t *testing.T) {
+	byteOrdered := []string{"C", "POSIX", "c", "C.UTF-8", "C.utf8"}
+	for _, c := range byteOrdered {
+		if !isByteOrderedCollation(c) {
+			t.Fatalf("expected %q to be treated as byte-ordered", c)
+		}
+	}
+	locale := []string{"en_US.UTF-8", "en_US.utf8", "en-US-x-icu", "und-x-icu", ""}
+	for _, c := range locale {
+		if isByteOrderedCollation(c) {
+			t.Fatalf("expected %q to be treated as locale-aware", c)
+		}
+	}
+}