1 files changed, 74 insertions, 69 deletions
diff --git a/spec/ruby/library/zlib/crc_table_spec.rb b/spec/ruby/library/zlib/crc_table_spec.rb
index f7fc2749fa..de8876086b 100644
--- a/spec/ruby/library/zlib/crc_table_spec.rb
+++ b/spec/ruby/library/zlib/crc_table_spec.rb
@@ -2,74 +2,79 @@ require_relative '../../spec_helper'
 require "zlib"
 
 describe "Zlib.crc_table" do
-
-  it "returns the same value as zlib's get_crc_table()" do
-    Zlib.crc_table.should == [
-      0, 1996959894, 3993919788, 2567524794,
-      124634137, 1886057615, 3915621685, 2657392035,
-      249268274, 2044508324, 3772115230, 2547177864,
-      162941995, 2125561021, 3887607047, 2428444049,
-      498536548, 1789927666, 4089016648, 2227061214,
-      450548861, 1843258603, 4107580753, 2211677639,
-      325883990, 1684777152, 4251122042, 2321926636,
-      335633487, 1661365465, 4195302755, 2366115317,
-      997073096, 1281953886, 3579855332, 2724688242,
-      1006888145, 1258607687, 3524101629, 2768942443,
-      901097722, 1119000684, 3686517206, 2898065728,
-      853044451, 1172266101, 3705015759, 2882616665,
-      651767980, 1373503546, 3369554304, 3218104598,
-      565507253, 1454621731, 3485111705, 3099436303,
-      671266974, 1594198024, 3322730930, 2970347812,
-      795835527, 1483230225, 3244367275, 3060149565,
-      1994146192, 31158534, 2563907772, 4023717930,
-      1907459465, 112637215, 2680153253, 3904427059,
-      2013776290, 251722036, 2517215374, 3775830040,
-      2137656763, 141376813, 2439277719, 3865271297,
-      1802195444, 476864866, 2238001368, 4066508878,
-      1812370925, 453092731, 2181625025, 4111451223,
-      1706088902, 314042704, 2344532202, 4240017532,
-      1658658271, 366619977, 2362670323, 4224994405,
-      1303535960, 984961486, 2747007092, 3569037538,
-      1256170817, 1037604311, 2765210733, 3554079995,
-      1131014506, 879679996, 2909243462, 3663771856,
-      1141124467, 855842277, 2852801631, 3708648649,
-      1342533948, 654459306, 3188396048, 3373015174,
-      1466479909, 544179635, 3110523913, 3462522015,
-      1591671054, 702138776, 2966460450, 3352799412,
-      1504918807, 783551873, 3082640443, 3233442989,
-      3988292384, 2596254646, 62317068, 1957810842,
-      3939845945, 2647816111, 81470997, 1943803523,
-      3814918930, 2489596804, 225274430, 2053790376,
-      3826175755, 2466906013, 167816743, 2097651377,
-      4027552580, 2265490386, 503444072, 1762050814,
-      4150417245, 2154129355, 426522225, 1852507879,
-      4275313526, 2312317920, 282753626, 1742555852,
-      4189708143, 2394877945, 397917763, 1622183637,
-      3604390888, 2714866558, 953729732, 1340076626,
-      3518719985, 2797360999, 1068828381, 1219638859,
-      3624741850, 2936675148, 906185462, 1090812512,
-      3747672003, 2825379669, 829329135, 1181335161,
-      3412177804, 3160834842, 628085408, 1382605366,
-      3423369109, 3138078467, 570562233, 1426400815,
-      3317316542, 2998733608, 733239954, 1555261956,
-      3268935591, 3050360625, 752459403, 1541320221,
-      2607071920, 3965973030, 1969922972, 40735498,
-      2617837225, 3943577151, 1913087877, 83908371,
-      2512341634, 3803740692, 2075208622, 213261112,
-      2463272603, 3855990285, 2094854071, 198958881,
-      2262029012, 4057260610, 1759359992, 534414190,
-      2176718541, 4139329115, 1873836001, 414664567,
-      2282248934, 4279200368, 1711684554, 285281116,
-      2405801727, 4167216745, 1634467795, 376229701,
-      2685067896, 3608007406, 1308918612, 956543938,
-      2808555105, 3495958263, 1231636301, 1047427035,
-      2932959818, 3654703836, 1088359270, 936918000,
-      2847714899, 3736837829, 1202900863, 817233897,
-      3183342108, 3401237130, 1404277552, 615818150,
-      3134207493, 3453421203, 1423857449, 601450431,
-      3009837614, 3294710456, 1567103746, 711928724,
-      3020668471, 3272380065, 1510334235, 755167117,
-    ]
+  # This spec fails when zlib.h and libz.so are not from the same version.
+  # In older zlib (< 1.2.7 it seems), get_crc_table() is stored as u64[],
+  # but in newer zlib, get_crc_table() is stored as u32[].
+  # Technically, there is ABI breakage between those zlib versions,
+  # but get_crc_table() is an "undocumented function" according to zlib.h.
+  guard -> { ENV["RUBY_SPEC_TEST_ZLIB_CRC_TABLE"] != "false" } do
+    it "returns the same value as zlib's get_crc_table()" do
+      Zlib.crc_table.should == [
+        0, 1996959894, 3993919788, 2567524794,
+        124634137, 1886057615, 3915621685, 2657392035,
+        249268274, 2044508324, 3772115230, 2547177864,
+        162941995, 2125561021, 3887607047, 2428444049,
+        498536548, 1789927666, 4089016648, 2227061214,
+        450548861, 1843258603, 4107580753, 2211677639,
+        325883990, 1684777152, 4251122042, 2321926636,
+        335633487, 1661365465, 4195302755, 2366115317,
+        997073096, 1281953886, 3579855332, 2724688242,
+        1006888145, 1258607687, 3524101629, 2768942443,
+        901097722, 1119000684, 3686517206, 2898065728,
+        853044451, 1172266101, 3705015759, 2882616665,
+        651767980, 1373503546, 3369554304, 3218104598,
+        565507253, 1454621731, 3485111705, 3099436303,
+        671266974, 1594198024, 3322730930, 2970347812,
+        795835527, 1483230225, 3244367275, 3060149565,
+        1994146192, 31158534, 2563907772, 4023717930,
+        1907459465, 112637215, 2680153253, 3904427059,
+        2013776290, 251722036, 2517215374, 3775830040,
+        2137656763, 141376813, 2439277719, 3865271297,
+        1802195444, 476864866, 2238001368, 4066508878,
+        1812370925, 453092731, 2181625025, 4111451223,
+        1706088902, 314042704, 2344532202, 4240017532,
+        1658658271, 366619977, 2362670323, 4224994405,
+        1303535960, 984961486, 2747007092, 3569037538,
+        1256170817, 1037604311, 2765210733, 3554079995,
+        1131014506, 879679996, 2909243462, 3663771856,
+        1141124467, 855842277, 2852801631, 3708648649,
+        1342533948, 654459306, 3188396048, 3373015174,
+        1466479909, 544179635, 3110523913, 3462522015,
+        1591671054, 702138776, 2966460450, 3352799412,
+        1504918807, 783551873, 3082640443, 3233442989,
+        3988292384, 2596254646, 62317068, 1957810842,
+        3939845945, 2647816111, 81470997, 1943803523,
+        3814918930, 2489596804, 225274430, 2053790376,
+        3826175755, 2466906013, 167816743, 2097651377,
+        4027552580, 2265490386, 503444072, 1762050814,
+        4150417245, 2154129355, 426522225, 1852507879,
+        4275313526, 2312317920, 282753626, 1742555852,
+        4189708143, 2394877945, 397917763, 1622183637,
+        3604390888, 2714866558, 953729732, 1340076626,
+        3518719985, 2797360999, 1068828381, 1219638859,
+        3624741850, 2936675148, 906185462, 1090812512,
+        3747672003, 2825379669, 829329135, 1181335161,
+        3412177804, 3160834842, 628085408, 1382605366,
+        3423369109, 3138078467, 570562233, 1426400815,
+        3317316542, 2998733608, 733239954, 1555261956,
+        3268935591, 3050360625, 752459403, 1541320221,
+        2607071920, 3965973030, 1969922972, 40735498,
+        2617837225, 3943577151, 1913087877, 83908371,
+        2512341634, 3803740692, 2075208622, 213261112,
+        2463272603, 3855990285, 2094854071, 198958881,
+        2262029012, 4057260610, 1759359992, 534414190,
+        2176718541, 4139329115, 1873836001, 414664567,
+        2282248934, 4279200368, 1711684554, 285281116,
+        2405801727, 4167216745, 1634467795, 376229701,
+        2685067896, 3608007406, 1308918612, 956543938,
+        2808555105, 3495958263, 1231636301, 1047427035,
+        2932959818, 3654703836, 1088359270, 936918000,
+        2847714899, 3736837829, 1202900863, 817233897,
+        3183342108, 3401237130, 1404277552, 615818150,
+        3134207493, 3453421203, 1423857449, 601450431,
+        3009837614, 3294710456, 1567103746, 711928724,
+        3020668471, 3272380065, 1510334235, 755167117,
+      ]
+    end
   end
-
 end