Fix handling of zero precision

include/fmt/format-inl.h

@@ -610,7 +610,7 @@ struct fixed_handler {
                           uint64_t error, int, bool integral) {
     FMT_ASSERT(remainder < divisor, "");
     buf[size++] = digit;
-    if (size != precision) return digits::more;
+    if (size < precision) return digits::more;
     if (!integral) {
       // Check if error * 2 < divisor with overflow prevention.
       // The check is not needed for the integral part because error = 1

test/grisu-test.cc

@@ -52,3 +52,7 @@ TEST(GrisuTest, Prettify) {
   EXPECT_EQ("12.34", fmt::format("{}", 1234e-2));
   EXPECT_EQ("0.001234", fmt::format("{}", 1234e-6));
 }
+
+TEST(GrisuTest, ZeroPrecision) {
+  EXPECT_EQ("1", fmt::format("{:.0}", 1.0));
+}