Issue #22364: Improved some re error messages using regex for hints.
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index e6f1f1d..0bce71e 100644
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -79,7 +79,7 @@
gid = self.groups
self.subpatterns.append(None)
if self.groups > MAXGROUPS:
- raise error("groups number is too large")
+ raise error("too many groups")
if name is not None:
ogid = self.groupdict.get(name, None)
if ogid is not None:
@@ -235,7 +235,7 @@
try:
char += self.decoded_string[index]
except IndexError:
- raise error("bogus escape (end of line)",
+ raise error("bad escape (end of pattern)",
self.string, len(self.string) - 1) from None
self.index = index + 1
self.next = char
@@ -263,8 +263,13 @@
c = self.next
self.__next()
if c is None:
- raise self.error("unterminated name")
+ if not result:
+ raise self.error("missing group name")
+ raise self.error("missing %s, unterminated name" % terminator,
+ len(result))
if c == terminator:
+ if not result:
+ raise self.error("missing group name", 1)
break
result += c
return result
@@ -318,19 +323,19 @@
# hexadecimal escape (exactly two digits)
escape += source.getwhile(2, HEXDIGITS)
if len(escape) != 4:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
return LITERAL, int(escape[2:], 16)
elif c == "u" and source.istext:
# unicode escape (exactly four digits)
escape += source.getwhile(4, HEXDIGITS)
if len(escape) != 6:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
return LITERAL, int(escape[2:], 16)
elif c == "U" and source.istext:
# unicode escape (exactly eight digits)
escape += source.getwhile(8, HEXDIGITS)
if len(escape) != 10:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
c = int(escape[2:], 16)
chr(c) # raise ValueError for invalid code
return LITERAL, c
@@ -339,7 +344,7 @@
escape += source.getwhile(2, OCTDIGITS)
c = int(escape[1:], 8)
if c > 0o377:
- raise source.error('octal escape value %r outside of '
+ raise source.error('octal escape value %s outside of '
'range 0-0o377' % escape, len(escape))
return LITERAL, c
elif c in DIGITS:
@@ -352,7 +357,7 @@
return LITERAL, ord(escape[1])
except ValueError:
pass
- raise source.error("bogus escape: %r" % escape, len(escape))
+ raise source.error("bad escape %s" % escape, len(escape))
def _escape(source, escape, state):
# handle escape code in expression
@@ -368,19 +373,19 @@
# hexadecimal escape
escape += source.getwhile(2, HEXDIGITS)
if len(escape) != 4:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
return LITERAL, int(escape[2:], 16)
elif c == "u" and source.istext:
# unicode escape (exactly four digits)
escape += source.getwhile(4, HEXDIGITS)
if len(escape) != 6:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
return LITERAL, int(escape[2:], 16)
elif c == "U" and source.istext:
# unicode escape (exactly eight digits)
escape += source.getwhile(8, HEXDIGITS)
if len(escape) != 10:
- raise ValueError
+ raise source.error("incomplete escape %s" % escape, len(escape))
c = int(escape[2:], 16)
chr(c) # raise ValueError for invalid code
return LITERAL, c
@@ -398,7 +403,7 @@
escape += source.get()
c = int(escape[1:], 8)
if c > 0o377:
- raise source.error('octal escape value %r outside of '
+ raise source.error('octal escape value %s outside of '
'range 0-0o377' % escape,
len(escape))
return LITERAL, c
@@ -406,11 +411,11 @@
group = int(escape[1:])
if group < state.groups:
if not state.checkgroup(group):
- raise source.error("cannot refer to open group",
+ raise source.error("cannot refer to an open group",
len(escape))
state.checklookbehindgroup(group, source)
return GROUPREF, group
- raise ValueError
+ raise source.error("invalid group reference", len(escape))
if len(escape) == 2:
if c in ASCIILETTERS:
import warnings
@@ -419,7 +424,7 @@
return LITERAL, ord(escape[1])
except ValueError:
pass
- raise source.error("bogus escape: %r" % escape, len(escape))
+ raise source.error("bad escape %s" % escape, len(escape))
def _parse_sub(source, state, nested=True):
# parse an alternation: a|b|c
@@ -427,12 +432,11 @@
items = []
itemsappend = items.append
sourcematch = source.match
+ start = source.tell()
while True:
itemsappend(_parse(source, state))
if not sourcematch("|"):
break
- if nested and source.next is not None and source.next != ")":
- raise source.error("pattern not properly closed")
if len(items) == 1:
return items[0]
@@ -480,8 +484,6 @@
raise source.error("conditional backref with more than two branches")
else:
item_no = None
- if source.next is not None and source.next != ")":
- raise source.error("pattern not properly closed")
subpattern = SubPattern(state)
subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
return subpattern
@@ -526,6 +528,7 @@
subpatternappend((LITERAL, _ord(this)))
elif this == "[":
+ here = source.tell() - 1
# character set
set = []
setappend = set.append
@@ -538,7 +541,8 @@
while True:
this = sourceget()
if this is None:
- raise source.error("unexpected end of regular expression")
+ raise source.error("unterminated character set",
+ source.tell() - here)
if this == "]" and set != start:
break
elif this[0] == "\\":
@@ -547,25 +551,28 @@
code1 = LITERAL, _ord(this)
if sourcematch("-"):
# potential range
- this = sourceget()
- if this is None:
- raise source.error("unexpected end of regular expression")
- if this == "]":
+ that = sourceget()
+ if that is None:
+ raise source.error("unterminated character set",
+ source.tell() - here)
+ if that == "]":
if code1[0] is IN:
code1 = code1[1][0]
setappend(code1)
setappend((LITERAL, _ord("-")))
break
- if this[0] == "\\":
- code2 = _class_escape(source, this)
+ if that[0] == "\\":
+ code2 = _class_escape(source, that)
else:
- code2 = LITERAL, _ord(this)
+ code2 = LITERAL, _ord(that)
if code1[0] != LITERAL or code2[0] != LITERAL:
- raise source.error("bad character range", len(this))
+ msg = "bad character range %s-%s" % (this, that)
+ raise source.error(msg, len(this) + 1 + len(that))
lo = code1[1]
hi = code2[1]
if hi < lo:
- raise source.error("bad character range", len(this))
+ msg = "bad character range %s-%s" % (this, that)
+ raise source.error(msg, len(this) + 1 + len(that))
setappend((RANGE, (lo, hi)))
else:
if code1[0] is IN:
@@ -617,10 +624,10 @@
if max >= MAXREPEAT:
raise OverflowError("the repetition number is too large")
if max < min:
- raise source.error("bad repeat interval",
+ raise source.error("min repeat greater than max repeat",
source.tell() - here)
else:
- raise source.error("not supported", len(this))
+ raise AssertionError("unsupported quantifier %r" % (char,))
# figure out which item to repeat
if subpattern:
item = subpattern[-1:]
@@ -641,39 +648,32 @@
subpatternappend((ANY, None))
elif this == "(":
- group = 1
+ start = source.tell() - 1
+ group = True
name = None
condgroup = None
if sourcematch("?"):
- group = 0
# options
char = sourceget()
if char is None:
- raise self.error("unexpected end of pattern")
+ raise source.error("unexpected end of pattern")
if char == "P":
# python extensions
if sourcematch("<"):
# named group: skip forward to end of name
name = source.getuntil(">")
- group = 1
- if not name:
- raise source.error("missing group name", 1)
if not name.isidentifier():
- raise source.error("bad character in group name "
- "%r" % name,
- len(name) + 1)
+ msg = "bad character in group name %r" % name
+ raise source.error(msg, len(name) + 1)
elif sourcematch("="):
# named backreference
name = source.getuntil(")")
- if not name:
- raise source.error("missing group name", 1)
if not name.isidentifier():
- raise source.error("bad character in backref "
- "group name %r" % name,
- len(name) + 1)
+ msg = "bad character in group name %r" % name
+ raise source.error(msg, len(name) + 1)
gid = state.groupdict.get(name)
if gid is None:
- msg = "unknown group name: {0!r}".format(name)
+ msg = "unknown group name %r" % name
raise source.error(msg, len(name) + 1)
state.checklookbehindgroup(gid, source)
subpatternappend((GROUPREF, gid))
@@ -682,16 +682,17 @@
char = sourceget()
if char is None:
raise source.error("unexpected end of pattern")
- raise source.error("unknown specifier: ?P%s" % char,
- len(char))
+ raise source.error("unknown extension ?P" + char,
+ len(char) + 2)
elif char == ":":
# non-capturing group
- group = 2
+ group = None
elif char == "#":
# comment
while True:
if source.next is None:
- raise source.error("unbalanced parenthesis")
+ raise source.error("missing ), unterminated comment",
+ source.tell() - start)
if sourceget() == ")":
break
continue
@@ -700,8 +701,11 @@
dir = 1
if char == "<":
char = sourceget()
- if char is None or char not in "=!":
- raise source.error("syntax error")
+ if char is None:
+ raise source.error("unexpected end of pattern")
+ if char not in "=!":
+ raise source.error("unknown extension ?<" + char,
+ len(char) + 2)
dir = -1 # lookbehind
lookbehindgroups = state.lookbehindgroups
if lookbehindgroups is None:
@@ -711,7 +715,8 @@
if lookbehindgroups is None:
state.lookbehindgroups = None
if not sourcematch(")"):
- raise source.error("unbalanced parenthesis")
+ raise source.error("missing ), unterminated subpattern",
+ source.tell() - start)
if char == "=":
subpatternappend((ASSERT, (dir, p)))
else:
@@ -720,13 +725,11 @@
elif char == "(":
# conditional backreference group
condname = source.getuntil(")")
- group = 2
- if not condname:
- raise source.error("missing group name", 1)
+ group = None
if condname.isidentifier():
condgroup = state.groupdict.get(condname)
if condgroup is None:
- msg = "unknown group name: {0!r}".format(condname)
+ msg = "unknown group name %r" % condname
raise source.error(msg, len(condname) + 1)
else:
try:
@@ -734,50 +737,48 @@
if condgroup < 0:
raise ValueError
except ValueError:
- raise source.error("bad character in group name",
- len(condname) + 1)
+ msg = "bad character in group name %r" % condname
+ raise source.error(msg, len(condname) + 1) from None
if not condgroup:
raise source.error("bad group number",
len(condname) + 1)
if condgroup >= MAXGROUPS:
- raise source.error("the group number is too large",
+ raise source.error("invalid group reference",
len(condname) + 1)
state.checklookbehindgroup(condgroup, source)
elif char in FLAGS:
# flags
- state.flags |= FLAGS[char]
- while source.next in FLAGS:
- state.flags |= FLAGS[sourceget()]
+ while True:
+ state.flags |= FLAGS[char]
+ char = sourceget()
+ if char is None:
+ raise source.error("missing )")
+ if char == ")":
+ break
+ if char not in FLAGS:
+ raise source.error("unknown flag", len(char))
verbose = state.flags & SRE_FLAG_VERBOSE
+ continue
else:
- raise source.error("unexpected end of pattern")
- if group:
- # parse group contents
- if group == 2:
- # anonymous group
- group = None
- else:
- try:
- group = state.opengroup(name)
- except error as err:
- raise source.error(err.msg, len(name) + 1)
- if condgroup:
- p = _parse_sub_cond(source, state, condgroup)
- else:
- p = _parse_sub(source, state)
- if not sourcematch(")"):
- raise source.error("unbalanced parenthesis")
- if group is not None:
- state.closegroup(group, p)
- subpatternappend((SUBPATTERN, (group, p)))
+ raise source.error("unknown extension ?" + char,
+ len(char) + 1)
+
+ # parse group contents
+ if group is not None:
+ try:
+ group = state.opengroup(name)
+ except error as err:
+ raise source.error(err.msg, len(name) + 1) from None
+ if condgroup:
+ p = _parse_sub_cond(source, state, condgroup)
else:
- while True:
- char = sourceget()
- if char is None:
- raise source.error("unexpected end of pattern")
- if char == ")":
- break
- raise source.error("unknown extension", len(char))
+ p = _parse_sub(source, state)
+ if not source.match(")"):
+ raise source.error("missing ), unterminated subpattern",
+ source.tell() - start)
+ if group is not None:
+ state.closegroup(group, p)
+ subpatternappend((SUBPATTERN, (group, p)))
elif this == "^":
subpatternappend((AT, AT_BEGINNING))
@@ -786,7 +787,7 @@
subpattern.append((AT, AT_END))
else:
- raise source.error("parser error", len(this))
+ raise AssertionError("unsupported special character %r" % (char,))
return subpattern
@@ -804,7 +805,7 @@
raise ValueError("ASCII and UNICODE flags are incompatible")
else:
if flags & SRE_FLAG_UNICODE:
- raise ValueError("can't use UNICODE flag with a bytes pattern")
+ raise ValueError("cannot use UNICODE flag with a bytes pattern")
if flags & SRE_FLAG_LOCALE and flags & SRE_FLAG_ASCII:
import warnings
warnings.warn("ASCII and LOCALE flags are incompatible. "
@@ -826,11 +827,8 @@
p.pattern.flags = fix_flags(str, p.pattern.flags)
if source.next is not None:
- if source.next == ")":
- raise source.error("unbalanced parenthesis")
- else:
- raise source.error("bogus characters at end of regular expression",
- len(tail))
+ assert source.next == ")"
+ raise source.error("unbalanced parenthesis")
if flags & SRE_FLAG_DEBUG:
p.dump()
@@ -866,26 +864,25 @@
c = this[1]
if c == "g":
name = ""
- if s.match("<"):
- name = s.getuntil(">")
- if not name:
- raise s.error("missing group name", 1)
- try:
- index = int(name)
- if index < 0:
- raise s.error("negative group number", len(name) + 1)
- if index >= MAXGROUPS:
- raise s.error("the group number is too large",
- len(name) + 1)
- except ValueError:
- if not name.isidentifier():
- raise s.error("bad character in group name",
- len(name) + 1)
+ if not s.match("<"):
+ raise s.error("missing <")
+ name = s.getuntil(">")
+ if name.isidentifier():
try:
index = pattern.groupindex[name]
except KeyError:
- msg = "unknown group name: {0!r}".format(name)
- raise IndexError(msg)
+ raise IndexError("unknown group name %r" % name)
+ else:
+ try:
+ index = int(name)
+ if index < 0:
+ raise ValueError
+ except ValueError:
+ raise s.error("bad character in group name %r" % name,
+ len(name) + 1) from None
+ if index >= MAXGROUPS:
+ raise s.error("invalid group reference",
+ len(name) + 1)
addgroup(index)
elif c == "0":
if s.next in OCTDIGITS:
@@ -903,7 +900,7 @@
isoctal = True
c = int(this[1:], 8)
if c > 0o377:
- raise s.error('octal escape value %r outside of '
+ raise s.error('octal escape value %s outside of '
'range 0-0o377' % this, len(this))
lappend(chr(c))
if not isoctal: