Release Manager · Release Manager · commit 8e204dde3b36 · 2025-02-21T02:00:21.000+01:00
sagemathgh-39479: Fixed crash when exp(0) of p-adic numbers is called Fixes sagemath#38037. Fixes crash when exp(0) is called when using p-adic numbers. Since the unit part of 0 does not exist it was causing a crash. Therefore, to fix this bug we check if our exponent is exactly 0 and if it is return 1 immediately. Also added a doctest to verify that the issue has been fixed. ### 📝 Checklist  - [X] The title is concise and informative. - [X] The description explains in detail what this PR is about. - [X] I have linked a relevant issue or discussion. - [X] I have created tests covering the changes. - [X] I have updated the documentation and checked the documentation preview. ### ⌛ Dependencies URL: sagemath#39479 Reported by: Noel-Roemmele Reviewer(s):
diff --git a/src/sage/rings/padics/padic_generic_element.pyx b/src/sage/rings/padics/padic_generic_element.pyx
@@ -2959,6 +2959,14 @@ cdef class pAdicGenericElement(LocalGenericElement):
             sage: x.exp(algorithm='generic')   # indirect doctest                       # needs sage.libs.ntl
             1 + w*7 + (4*w + 2)*7^2 + (w + 6)*7^3 + 5*7^4 + O(7^5)
 
+        TESTS:
+
+        Verify that :issue:`38037` is fixed::
+
+            sage: R.<a> = Zq(9)
+            sage: exp(R.zero())
+            1 + O(3^20)
+
         AUTHORS:
 
         - Genya Zaytman (2007-02-15)
@@ -2973,6 +2981,8 @@ cdef class pAdicGenericElement(LocalGenericElement):
         R=self.parent()
         p=self.parent().prime()
         e=self.parent().absolute_e()
+        if self._is_exact_zero():
+            return R.one()
         x_unit=self.unit_part()
         p_unit=R(p).unit_part().lift_to_precision()
         x_val=self.valuation()
