Regular expressions involving a (x){0} term are
simplified by removing this term from the
expression, just before the expression is compiled.
The number of subexpressions is evaluated before
the simplification. The number of capture instructions
in the compiled expressions is not necessarily in line
with the number of subexpressions.
When the ReplaceAll(String) methods are used, a number
of capture slots (nmatch) is evaluated as 2*(s+1)
(s being the number of subexpressions).
In some case, it can be higher than the number of capture
instructions evaluated at compile time, resulting in a
panic when the internal slices of regexp.machine
are resized to this value.
Fixed by capping the number of capture slots to the number
of capture instructions.
I must say I do not really see the benefits of setting
nmatch lower than re.prog.NumCap using this 2*(s+1) formula,
so perhaps this can be further simplified.
Fixes#11178Fixes#11176
Change-Id: I21415e8ef2dd5f2721218e9a679f7f6bfb76ae9b
Reviewed-on: https://go-review.googlesource.com/14013
Reviewed-by: Russ Cox <rsc@golang.org>
The existing comment for regex.Split contains a plain text example,
while many of the other regex functions have runnable examples. This
change provides a runnable example for Split.
Change-Id: I5373f57f532fe843d7d0adcf4b513061ec797047
Reviewed-on: https://go-review.googlesource.com/14737
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In 1.6, go doc is more likely to be available.
Change-Id: I970ad1d3317b35273f5c8d830f75713d3570c473
Reviewed-on: https://go-review.googlesource.com/10518
Reviewed-by: Andrew Gerrand <adg@golang.org>
Replaced code.google.com/p/re2/ with github.com/google/re2/ and
updated the file names (re2-exhaustive.txt.bz2 not re2.txt.gz)
as well as the re2 make command (make log).
Change-Id: I15937b0b8a898d78d45366857ed86421c8d69960
Reviewed-on: https://go-review.googlesource.com/9372
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This update makes maxBacktrackLen return 0 if
len(prog.Inst) > maxBacktrackProg. This prevents an attempt to
backtrack against a nil bitstate.
Fixes#10319
Change-Id: Icdbeb2392782ccf66f9d0a70ea57af22fb93f01b
Reviewed-on: https://go-review.googlesource.com/8473
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The stack blowout can no longer happen,
but we can still test that too-complex regexps
are rejected.
Replacement for CL 162770043.
LGTM=iant, r
R=r, iant
CC=bradfitz, golang-codereviews
https://golang.org/cl/162860043
This is already tested by TestRE2Exhaustive, but the build has
not broken because that test is not run when using -test.short.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/155580043
Didier Spezia
Seth Hoenig
Michael Matloob
Rob Pike
Dmitry Savintsev
Matthew Brennan
Brad Fitzpatrick
Josh Bleecher Snyder
Shenghou Ma
Robin Eklind
Russ Cox
Ian Lance Taylor