On Tue, Mar 11, 2008 at 09:11:28PM -0700, Junio C Hamano wrote:
> Besides tests, I think we have invocations of "tr" that Solaris people
> might want to audit in the real scripts. POSIX does not require [] around
> the strings, but when from-string and to-string are of the same length,
> having [] around them would not hurt (they transliterate to themselves)
> and that is the only reason why we tend to use [] form to help potential
> porters to ancient System V systems ;-)
I'm not sure that it is always OK to just put in extra brackets, at
least in the case of multiple ranges. Consider the patch I just posted:
$ uname -a
SunOS tokyo 5.8 Generic_117350-47 sun4u sparc SUNW,Ultra-4
# what we have now, ok with bsd
$ echo foo | /usr/ucb/tr '[A-Za-z]' '[N-ZA-Mn-za-m]'
sbb
# what we have now, broken with SysV because of multiple ranges
echo foo | /usr/bin/tr '[A-Za-z]' '[N-ZA-Mn-za-m]'
Bad string
# potential fix, break multiple ranges. works with SysV
echo foo | /usr/bin/tr '[A-Z][a-z]' '[N-Z][A-M][n-z][a-m]'
sbb
# but here it breaks bsd
echo foo | /usr/ucb/tr '[A-Z][a-z]' '[N-Z][A-M][n-z][a-m]'
qzz
which makes no sense to me at all. If it were ignoring the duplicated
'[' on input, then I could understand a shift of one character. But
there is a shift of two characters.
> bisect has "tr '[\012]' ' '" which I think we can get rid of by rewriting
> the users of the resulting string.
This one is just being overzealous with the brackets. There is no need
for them unless there is a character sequence. This works correctly as
tr '\012' ' '
at least using the Solaris SysV tr.
Below is a patch that fixes all of the problematic sites I found. Each
fix type was hand-tested with the Solaris SysV and UCB versions of tr,
and the tests ran successfully on Linux. On Solaris, I tried the tests
using /usr/bin/tr. However, I ran into problems with t1300, which tries:
tr '\000' 'Q'
It seems that /usr/bin/tr silently removes NULs from the input stream:
$ printf 'foo\000bar' | xxd
0000000: 666f 6f00 6261 72 foo.bar
$ printf 'foo\000bar' | /usr/bin/tr '\000' 'Q' | xxd
0000000: 666f 6f62 6172 foobar
I don't think there is an easy way around this; we might have to switch
to using perl.
-- >8 --
tr portability fixes
Specifying character ranges in tr differs between System V
and POSIX. In System V, brackets are required (e.g.,
'[A-Z]'), whereas in POSIX they are not.
We can mostly get around this by just using the bracket form
for both sets, as in:
tr '[A-Z] '[a-z]'
in which case POSIX interpets this as "'[' becomes '['",
which is OK.
However, this doesn't work with multiple sequences, like:
# rot13
tr '[A-Z][a-z]' '[N-Z][A-M][n-z][a-m]'
where the POSIX version does not behave the same as the
System V version. In this case, we must simply enumerate the
sequence.
This patch fixes problematic uses of tr in git scripts and
test scripts in one of three ways:
- if a single sequence, make sure it uses brackets
- if multiple sequences, enumerate
- if extra brackets (e.g., tr '[A]' 'a'), eliminate
brackets
---
git-bisect.sh | 4 ++--
git-filter-branch.sh | 4 ++--
t/t4022-diff-rewrite.sh | 5 ++++-
t/t7003-filter-branch.sh | 2 +-
4 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/git-bisect.sh b/git-bisect.sh
index 2c32d0b..48fb92d 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -293,14 +293,14 @@ bisect_next() {
bisect_next_check good
skip=$(git for-each-ref --format='%(objectname)' \
- "refs/bisect/skip-*" | tr '[\012]' ' ') || exit
+ "refs/bisect/skip-*" | tr '\012' ' ') || exit
BISECT_OPT=''
test -n "$skip" && BISECT_OPT='--bisect-all'
bad=$(git rev-parse --verify refs/bisect/bad) &&
good=$(git for-each-ref --format='^%(objectname)' \
- "refs/bisect/good-*" | tr '[\012]' ' ') &&
+ "refs/bisect/good-*" | tr '\012' ' ') &&
eval="git rev-list --bisect-vars $BISECT_OPT $good $bad --" &&
eval="$eval $(cat "$GIT_DIR/BISECT_NAMES")" &&
eval=$(filter_skipped "$eval" "$skip") &&
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 010353a..59cf023 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -58,8 +58,8 @@ eval "$functions"
# "author" or "committer
set_ident () {
- lid="$(echo "$1" | tr "A-Z" "a-z")"
- uid="$(echo "$1" | tr "a-z" "A-Z")"
+ lid="$(echo "$1" | tr "[A-Z]" "[a-z]")"
+ uid="$(echo "$1" | tr "[a-z]" "[A-Z]")"
pick_id_script='
/^'$lid' /{
s/'\''/'\''\\'\'\''/g
diff --git a/t/t4022-diff-rewrite.sh b/t/t4022-diff-rewrite.sh
index 6de4acb..bf996fc 100755
--- a/t/t4022-diff-rewrite.sh
+++ b/t/t4022-diff-rewrite.sh
@@ -8,7 +8,10 @@ test_expect_success setup '
cat ../../COPYING >test &&
git add test &&
- tr 'a-zA-Z' 'n-za-mN-ZA-M' <../../COPYING >test
+ tr \
+ "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+ "nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM" \
+ <../../COPYING >test
'
diff --git a/t/t7003-filter-branch.sh b/t/t7003-filter-branch.sh
index 6e14bf1..553131f 100755
--- a/t/t7003-filter-branch.sh
+++ b/t/t7003-filter-branch.sh
@@ -4,7 +4,7 @@ test_description='git-filter-branch'
. ./test-lib.sh
make_commit () {
- lower=$(echo $1 | tr A-Z a-z)
+ lower=$(echo $1 | tr '[A-Z]' '[a-z]')
echo $lower > $lower
git add $lower
test_tick
--
1.5.4.3.613.gdd757
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