wasm: fix rounding mode

Same as in topdown, we should have this be true in wasm: round(1.5) == 2 round(2.5) == 3 The default rounding mode for libmpdec's maxcontext was MPD_ROUND_HALF_EVEN, would would round 2.5 to 2. See https://www.bytereef.org/mpdecimal/doc/libmpdec/context.html#rounding Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
open-policy-agent · Dec 14, 2020 · f465b22 · f465b22
1 parent 9e52194
commit f465b22
Show file tree

Hide file tree

Showing 4 changed files with 12 additions and 81 deletions.
diff --git a/test/cases/testdata/arithmetic/test-arithmetic-0813.yaml b/test/cases/testdata/arithmetic/test-arithmetic-0813.yaml
@@ -5,95 +5,17 @@ cases:
     - 2
     - 3
     - 4
-    b:
-      v1: hello
-      v2: goodbye
-    c:
-    - x:
-      - true
-      - false
-      - foo
-      "y":
-      - null
-      - 3.14159
-      z:
-        p: true
-        q: false
-    d:
-      e:
-      - bar
-      - baz
-    f:
-    - xs:
-      - 1
-      ys:
-      - 2
-    - xs:
-      - 2
-      ys:
-      - 3
-    g:
-      a:
-      - 1
-      - 0
-      - 0
-      - 0
-      b:
-      - 0
-      - 2
-      - 0
-      - 0
-      c:
-      - 0
-      - 0
-      - 0
-      - 4
-    h:
-    - - 1
-      - 2
-      - 3
-    - - 2
-      - 3
-      - 4
-    l:
-    - a: bob
-      b: -1
-      c:
-      - 1
-      - 2
-      - 3
-      - 4
-    - a: alice
-      b: 1
-      c:
-      - 2
-      - 3
-      - 4
-      - 5
-      d: null
-    m: []
-    numbers:
-    - "1"
-    - "2"
-    - "3"
-    - "4"
-    strings:
-      bar: 2
-      baz: 3
-      foo: 1
-    three: 3
   modules:
   - |
-    package generated
+    package test
 
     p[z] {
       data.a[i] = x
-      __local0__ = i / x
-      y = __local0__
+      y = i / x
       round(y, z)
     }
   note: arithmetic/divide+round
-  query: data.generated.p = x
+  query: data.test.p = x
   sort_bindings: true
   want_result:
   - x:

diff --git a/test/wasm/assets/018_builtins.yaml b/test/wasm/assets/018_builtins.yaml
@@ -5,6 +5,12 @@ cases:
   - note: round built-in
     query: round(1.4,x)
     want_result: [{'x': 1}]
+  - note: round built-in ("halfs up")
+    query: round(1.5,x)
+    want_result: [{'x': 2}]
+  - note: round built-in ("halfs up not to even")
+    query: round(2.5,x)
+    want_result: [{'x': 3}]
   - note: plus built-in
     query: plus(1,1,x)
     want_result: [{'x': 2}]

diff --git a/wasm/src/mpd.c b/wasm/src/mpd.c
@@ -17,6 +17,7 @@ static void init(void)
 
         mpd_maxcontext(&max_ctx);
         max_ctx.traps = 0;
+        max_ctx.round = MPD_ROUND_HALF_UP; // .5 always rounded up
 
         one = mpd_qnew();
 

diff --git a/wasm/tests/test.c b/wasm/tests/test.c
@@ -1268,6 +1268,8 @@ void test_arithmetic(void)
     test("round -1.4 (float)", opa_number_as_float(opa_cast_number(opa_arith_round(opa_number_float(-1.4)))) == -1);
     test("round 1.5 (float)", opa_number_as_float(opa_cast_number(opa_arith_round(opa_number_float(1.5)))) == 2);
     test("round -1.5 (float)", opa_number_as_float(opa_cast_number(opa_arith_round(opa_number_float(-1.5)))) == -2);
+    test("round 2.5 (float)", opa_number_as_float(opa_cast_number(opa_arith_round(opa_number_float(2.5)))) == 3);
+    test("round -2.5 (float)", opa_number_as_float(opa_cast_number(opa_arith_round(opa_number_float(-2.5)))) == -3);
     test("plus 1+2", opa_number_as_float(opa_cast_number(opa_arith_plus(opa_number_float(1), opa_number_float(2)))) == 3);
     test("minus 3-2", opa_number_as_float(opa_cast_number(opa_arith_minus(opa_number_float(3), opa_number_float(2)))) == 1);