Issue #25953: re.sub() now raises an error for invalid numerical group
reference in replacement template even if the pattern is not found in
the string. Error message for invalid group reference now includes the
group index and the position of the reference.
Based on patch by SilentGhost.
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index 3d38673..ab37fd3 100644
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -395,7 +395,7 @@
len(escape))
state.checklookbehindgroup(group, source)
return GROUPREF, group
- raise source.error("invalid group reference", len(escape))
+ raise source.error("invalid group reference %d" % group, len(escape) - 1)
if len(escape) == 2:
if c in ASCIILETTERS:
raise source.error("bad escape %s" % escape, len(escape))
@@ -725,8 +725,8 @@
raise source.error("bad group number",
len(condname) + 1)
if condgroup >= MAXGROUPS:
- raise source.error("invalid group reference",
- len(condname) + 1)
+ msg = "invalid group reference %d" % condgroup
+ raise source.error(msg, len(condname) + 1)
state.checklookbehindgroup(condgroup, source)
elif char in FLAGS or char == "-":
# flags
@@ -883,7 +883,9 @@
literals = []
literal = []
lappend = literal.append
- def addgroup(index):
+ def addgroup(index, pos):
+ if index > pattern.groups:
+ raise s.error("invalid group reference %d" % index, pos)
if literal:
literals.append(''.join(literal))
del literal[:]
@@ -916,9 +918,9 @@
raise s.error("bad character in group name %r" % name,
len(name) + 1) from None
if index >= MAXGROUPS:
- raise s.error("invalid group reference",
+ raise s.error("invalid group reference %d" % index,
len(name) + 1)
- addgroup(index)
+ addgroup(index, len(name) + 1)
elif c == "0":
if s.next in OCTDIGITS:
this += sget()
@@ -939,7 +941,7 @@
'range 0-0o377' % this, len(this))
lappend(chr(c))
if not isoctal:
- addgroup(int(this[1:]))
+ addgroup(int(this[1:]), len(this) - 1)
else:
try:
this = chr(ESCAPES[this][1])
@@ -966,5 +968,5 @@
for index, group in groups:
literals[index] = g(group) or empty
except IndexError:
- raise error("invalid group reference")
+ raise error("invalid group reference %d" % index)
return empty.join(literals)