| Message ID | 20190101231949.8184-1-szeder.dev@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | test-lib: check Bash version for '-x' without using shell arrays | expand |
Am 02.01.19 um 00:19 schrieb SZEDER Gábor: > Alas, it has been reported that NetBSD's /bin/sh does complain about > them: > > ./test-lib.sh: 327: Syntax error: Bad substitution > > where line 327 contains the first ${BASH_VERSINFO[0]} array access. > diff --git a/t/test-lib.sh b/t/test-lib.sh > index 0f1faa24b2..f47a191e3b 100644 > --- a/t/test-lib.sh > +++ b/t/test-lib.sh > @@ -324,9 +324,12 @@ do > # isn't executed with a suitable Bash version. > if test -z "$test_untraceable" || { > test -n "$BASH_VERSION" && { > - test ${BASH_VERSINFO[0]} -gt 4 || { > - test ${BASH_VERSINFO[0]} -eq 4 && > - test ${BASH_VERSINFO[1]} -ge 1 > + bash_major=${BASH_VERSION%%.*} > + bash_minor=${BASH_VERSION#*.} > + bash_minor=${bash_minor%%.*} > + test $bash_major -gt 4 || { > + test $bash_major -eq 4 && > + test $bash_minor -ge 1 > } > } > } > Would it perhaps be simpler to just hide the syntax behind eval? Like if test -z "$test_untraceable" || { test -n "$BASH_VERSION" && eval ' test ${BASH_VERSINFO[0]} -gt 4 || { test ${BASH_VERSINFO[0]} -eq 4 && test ${BASH_VERSINFO[1]} -ge 1 } ' -- Hannes
Johannes Sixt <j6t@kdbg.org> writes: > Would it perhaps be simpler to just hide the syntax behind eval? Like > > if test -z "$test_untraceable" || { > test -n "$BASH_VERSION" && eval ' > test ${BASH_VERSINFO[0]} -gt 4 || { > test ${BASH_VERSINFO[0]} -eq 4 && > test ${BASH_VERSINFO[1]} -ge 1 > } > ' It indeed is somewhat easier to see that your version does exactly the same as the original than the posted patch, but the pattern substitutions are not all that bad, either.
On Tue, Jan 1, 2019 at 6:20 PM SZEDER Gábor <szeder.dev@gmail.com> wrote: > [...] > To my understanding both shells are right and conform to POSIX, > because the standard allows both behavior by stating the following s/behavior/behaviors/ > under '2.8.1 Consequences of Shell Errors': > > Reported-by: Max Kirillov <max@max630.net> > Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Tested-By: Carlo Marcelo Arenas Belón <carenas@gmail.com>
On Wed, Jan 02, 2019 at 01:20:47AM +0100, Johannes Sixt wrote: > > diff --git a/t/test-lib.sh b/t/test-lib.sh > > index 0f1faa24b2..f47a191e3b 100644 > > --- a/t/test-lib.sh > > +++ b/t/test-lib.sh > > @@ -324,9 +324,12 @@ do > > # isn't executed with a suitable Bash version. > > if test -z "$test_untraceable" || { > > test -n "$BASH_VERSION" && { > > - test ${BASH_VERSINFO[0]} -gt 4 || { > > - test ${BASH_VERSINFO[0]} -eq 4 && > > - test ${BASH_VERSINFO[1]} -ge 1 > > + bash_major=${BASH_VERSION%%.*} > > + bash_minor=${BASH_VERSION#*.} > > + bash_minor=${bash_minor%%.*} > > + test $bash_major -gt 4 || { > > + test $bash_major -eq 4 && > > + test $bash_minor -ge 1 > > } > > } > > } > > > > Would it perhaps be simpler to just hide the syntax behind eval? Like > > if test -z "$test_untraceable" || { > test -n "$BASH_VERSION" && eval ' > test ${BASH_VERSINFO[0]} -gt 4 || { > test ${BASH_VERSINFO[0]} -eq 4 && > test ${BASH_VERSINFO[1]} -ge 1 > } > ' That was my first thought, too. :) The parsing here is simple enough that I'd be fine either with the original patch, or an eval-based version (and otherwise, the goal and description seem quite good to me). -Peff
On Wed, Jan 02, 2019 at 12:19:49AM +0100, SZEDER Gábor wrote: > To my understanding both shells are right and conform to POSIX, > because the standard allows both behavior by stating the following > under '2.8.1 Consequences of Shell Errors': > > "An expansion error is one that occurs when the shell expansions > define in wordexp are carried out (for example, "${x!y}", because That "define" above always stops my (non-native) English parser for a moment or two... shouldn't it be s/define/defined/ ? It's not a copy-paste error, POSIX does indeed write "define" there, see: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_08_01 (First paragraph below the table and the Notes.) > '!' is not a valid operator); an implementation may treat these as > syntax errors if it is able to detect them during tokenization, > rather than during expansion." >
diff --git a/t/test-lib.sh b/t/test-lib.sh index 0f1faa24b2..f47a191e3b 100644 --- a/t/test-lib.sh +++ b/t/test-lib.sh @@ -324,9 +324,12 @@ do # isn't executed with a suitable Bash version. if test -z "$test_untraceable" || { test -n "$BASH_VERSION" && { - test ${BASH_VERSINFO[0]} -gt 4 || { - test ${BASH_VERSINFO[0]} -eq 4 && - test ${BASH_VERSINFO[1]} -ge 1 + bash_major=${BASH_VERSION%%.*} + bash_minor=${BASH_VERSION#*.} + bash_minor=${bash_minor%%.*} + test $bash_major -gt 4 || { + test $bash_major -eq 4 && + test $bash_minor -ge 1 } } }
One of our test scripts, 't1510-repo-setup.sh' [1], still can't be reliably run with '-x' tracing enabled, unless it's executed with a Bash version supporting BASH_XTRACEFD (since v4.1). We have a lengthy condition to check the version of the shell running the test script, and disable tracing if it's not executed with a suitable Bash version [2]. This condition uses non-portable shell array accesses to easily get Bash's major and minor version number. This didn't seem to be problematic, because the simple commands expanding those array accesses are only executed when the test script is actually run with Bash. When run with Dash, the only shell I have at hand that doesn't support shell arrays, there are no issues, as it apparently skips right over the non-executed simple commands without noticing the non-supported constructs. Alas, it has been reported that NetBSD's /bin/sh does complain about them: ./test-lib.sh: 327: Syntax error: Bad substitution where line 327 contains the first ${BASH_VERSINFO[0]} array access. To my understanding both shells are right and conform to POSIX, because the standard allows both behavior by stating the following under '2.8.1 Consequences of Shell Errors': "An expansion error is one that occurs when the shell expansions define in wordexp are carried out (for example, "${x!y}", because '!' is not a valid operator); an implementation may treat these as syntax errors if it is able to detect them during tokenization, rather than during expansion." Avoid this issue with NetBSD's /bin/sh (and potentially with other, less common shells) by using a couple of parameter expansions to extract the major and minor version numbers from $BASH_VERSION. [1] 5827506928 (t1510-repo-setup: mark as untraceable with '-x', 2018-02-24) [2] 5fc98e79fc (t: add means to disable '-x' tracing for individual test scripts, 2018-02-24) Reported-by: Max Kirillov <max@max630.net> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> --- This will certainly conflict with patches 3 and 6 in my stress testing patch series at https://public-inbox.org/git/20181230191629.3232-1-szeder.dev@gmail.com/T/#u t/test-lib.sh | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)