gh-35310: Fix radius and diameter for digraphs with non-comparable vertices

Fixes #35300.

### 📚 Description

We specify an ordering of the vertices in the call to `eccentricity`.
This way we fix both `radius` and `diameter`.

### 📝 Checklist

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### ⌛ Dependencies
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URL: #35310
Reported by: David Coudert
Reviewer(s): Frédéric Chapoton

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=c9dfa61ff70a2dceec85ad01fc37ee42232402c0
-md5=7479fb53c1b9fd56aea37f83a34cdac3
-cksum=3525422540
+sha1=a2e3104800baa46c2b8a8f85d7c27c4e46f8de3d
+md5=948e0a3542ef1e0a42dd275d183c5478
+cksum=1690902157

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-4452928a1a41758883e2f0e3a445b015dfa0e593
+4f29240074c53ae1e439b4a02b1be86b2e80aa68

src/sage/graphs/digraph.py

@@ -2259,7 +2259,7 @@ def eccentricity(self, v=None, by_weight=False, algorithm=None,
                 if with_labels:
                     return dict(zip(v, eccentricity(self, algorithm=algo, vertex_list=v)))
                 else:
-                    return eccentricity(self, algorithm=algo)
+                    return eccentricity(self, algorithm=algo, vertex_list=v)
 
             if algorithm in ['Floyd-Warshall-Python', 'Floyd-Warshall-Cython', 'Johnson_Boost']:
                 dist_dict = self.shortest_path_all_pairs(by_weight=by_weight, algorithm=algorithm,
@@ -2353,11 +2353,17 @@ def radius(self, by_weight=False, algorithm=None, weight_function=None,
             Traceback (most recent call last):
             ...
             ValueError: radius is not defined for the empty DiGraph
+
+        Check that :trac:`35300` is fixed::
+
+            sage: H = DiGraph([[42, 'John'], [(42, 'John')]])
+            sage: H.radius()
+            1
         """
         if not self.order():
             raise ValueError("radius is not defined for the empty DiGraph")
 
-        return min(self.eccentricity(v=None, by_weight=by_weight,
+        return min(self.eccentricity(v=list(self), by_weight=by_weight,
                                      weight_function=weight_function,
                                      check_weight=check_weight,
                                      algorithm=algorithm))
@@ -2486,6 +2492,15 @@ def diameter(self, by_weight=False, algorithm=None, weight_function=None,
             3
             sage: G.diameter(algorithm='DiFUB', by_weight=True)
             3.0
+
+        Check that :trac:`35300` is fixed::
+
+            sage: H = DiGraph([[42, 'John'], [(42, 'John')]])
+            sage: H.diameter()
+            +Infinity
+            sage: H.add_edge('John', 42)
+            sage: H.diameter()
+            1
         """
         if not self.order():
             raise ValueError("diameter is not defined for the empty DiGraph")
@@ -2517,7 +2532,7 @@ def diameter(self, by_weight=False, algorithm=None, weight_function=None,
             from sage.graphs.distances_all_pairs import diameter
             return diameter(self, algorithm='standard')
 
-        return max(self.eccentricity(v=None, by_weight=by_weight,
+        return max(self.eccentricity(v=list(self), by_weight=by_weight,
                                      weight_function=weight_function,
                                      check_weight=False,
                                      algorithm=algorithm))