From 933d3241eb23d6857716810bedfaf56123111a6a Mon Sep 17 00:00:00 2001
From: Dan Schult <dschult@colgate.edu>
Date: Sat, 7 Jul 2018 14:07:58 -0400
Subject: [PATCH] Fix StopIteration handling which breaks in python 3.7
See #3046
---
rebase against stable release
.../algorithms/connectivity/edge_augmentation.py | 12 +++++++++---
networkx/algorithms/connectivity/edge_kcomponents.py | 2 +-
networkx/algorithms/traversal/edgedfs.py | 2 +-
networkx/generators/classic.py | 2 ++
networkx/readwrite/sparse6.py | 10 ++++++++--
5 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/networkx/algorithms/connectivity/edge_augmentation.py b/networkx/algorithms/connectivity/edge_augmentation.py
index cd8c748f..21512d7c 100644
--- a/networkx/algorithms/connectivity/edge_augmentation.py
+++ b/networkx/algorithms/connectivity/edge_augmentation.py
@@ -813,7 +813,10 @@ def unconstrained_bridge_augmentation(G):
A2 = [tuple(leafs)]
else:
# Choose an arbitrary non-leaf root
- root = next(n for n, d in T.degree() if d > 1)
+ try:
+ root = next(n for n, d in T.degree() if d > 1)
+ except StopIteration: # no nodes found with degree > 1
+ return
# order the leaves of C by (induced directed) preorder
v2 = [n for n in nx.dfs_preorder_nodes(T, root) if T.degree(n) == 1]
# connecting first half of the leafs in pre-order to the second
@@ -954,7 +957,10 @@ def weighted_bridge_augmentation(G, avail, weight=None):
# nx.least_common_ancestor on the reversed Tree.
# Pick an arbitrary leaf from C as the root
- root = next(n for n in C.nodes() if C.degree(n) == 1)
+ try:
+ root = next(n for n, d in C.degree() if d == 1)
+ except StopIteration: # no nodes found with degree == 1
+ return
# Root C into a tree TR by directing all edges away from the root
# Note in their paper T directs edges towards the root
TR = nx.dfs_tree(C, root)
@@ -1230,7 +1236,7 @@ def greedy_k_edge_augmentation(G, k, avail=None, weight=None, seed=None):
done = is_k_edge_connected(G, k)
if done:
- raise StopIteration()
+ return
if avail is None:
# all edges are available
avail_uv = list(complement_edges(G))
diff --git a/networkx/algorithms/connectivity/edge_kcomponents.py b/networkx/algorithms/connectivity/edge_kcomponents.py
index 37bf61dc..f9b4364c 100644
--- a/networkx/algorithms/connectivity/edge_kcomponents.py
+++ b/networkx/algorithms/connectivity/edge_kcomponents.py
@@ -573,7 +573,7 @@ def general_k_edge_subgraphs(G, k):
if G.number_of_nodes() < k:
for node in G.nodes():
yield G.subgraph([node]).copy()
- raise StopIteration()
+ return
# Intermediate results
R0 = {G.subgraph(cc).copy() for cc in find_ccs(G)}
diff --git a/networkx/algorithms/traversal/edgedfs.py b/networkx/algorithms/traversal/edgedfs.py
index 5434057d..b9d442b6 100644
--- a/networkx/algorithms/traversal/edgedfs.py
+++ b/networkx/algorithms/traversal/edgedfs.py
@@ -152,7 +152,7 @@ def edge_dfs(G, source=None, orientation='original'):
"""
nodes = list(G.nbunch_iter(source))
if not nodes:
- raise StopIteration
+ return
kwds = {'data': False}
if G.is_multigraph():
diff --git a/networkx/generators/classic.py b/networkx/generators/classic.py
index 22741a37..10710db4 100644
--- a/networkx/generators/classic.py
+++ b/networkx/generators/classic.py
@@ -54,6 +54,8 @@ __all__ = ['balanced_tree',
# -------------------------------------------------------------------
def _tree_edges(n, r):
+ if n == 0:
+ return
# helper function for trees
# yields edges in rooted tree at 0 with n nodes and branching ratio r
nodes = iter(range(n))
diff --git a/networkx/readwrite/sparse6.py b/networkx/readwrite/sparse6.py
index 00ccae60..6f404ca3 100644
--- a/networkx/readwrite/sparse6.py
+++ b/networkx/readwrite/sparse6.py
@@ -163,7 +163,10 @@ def from_sparse6_bytes(string):
while 1:
if dLen < 1:
- d = next(chunks)
+ try:
+ d = next(chunks)
+ except StopIteration:
+ return
dLen = 6
dLen -= 1
b = (d >> dLen) & 1 # grab top remaining bit
@@ -171,7 +174,10 @@ def from_sparse6_bytes(string):
x = d & ((1 << dLen) - 1) # partially built up value of x
xLen = dLen # how many bits included so far in x
while xLen < k: # now grab full chunks until we have enough
- d = next(chunks)
+ try:
+ d = next(chunks)
+ except StopIteration:
+ return
dLen = 6
x = (x << 6) + d
xLen += 6
--
2.18.0