Re: [PATCH] test-lib.sh: use printf instead of echo
Jonathan Nieder writes: > Junio C Hamano wrote: > ... >> I am a bit reluctant to name the helper "sane_echo" to declare "echo >> that interprets backslashes in the string is insane", though. For >> these "print a single line" uses, we are only interested in using a >> subset of the features offered by 'echo', but that does not mean the >> other features we do not want to trigger in our use is of no use to >> any sane person. > > In a portable script, uncareful use of 'echo' is always insane. I agree that makes sense and I actually think that it is a bit stronger than that. If a script is meant to be portable, there is no way to use "echo" on a string whose contents is unknown sanely. There is no "careful use is OK". > In a script tailored to an environment where echo behaves consistently > it is perfectly reasonable to use 'echo', but that's a different > story. In the context of git, saying "Here is the thing you should > always use instead of echo" is a good thing, in my opinion. That is true in my opinion, but that thing is also what you should always use instead of "printf '%s\n'". A guideline more useful for the users is "Here is the thing you should always use when literally emitting a single line.", isn't it? -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] test-lib.sh: use printf instead of echo
Junio C Hamano wrote: > Jonathan Nieder writes: >> We currently use "echo" all over the place (e.g., 'echo "$path"' in >> git-sh-setup), and every time we fix it there is a chance of making >> mistakes. I wonder if it would make sense to add a helper to make the >> echo calls easier to replace: > > I agree that we would benefit from having a helper to print a single > line, which we very often do, without having to worry about the > boilerplate '%s\n' of printf or the portability gotcha of echo. > > I am a bit reluctant to name the helper "sane_echo" to declare "echo > that interprets backslashes in the string is insane", though. For > these "print a single line" uses, we are only interested in using a > subset of the features offered by 'echo', but that does not mean the > other features we do not want to trigger in our use is of no use to > any sane person. In a portable script, uncareful use of 'echo' is always insane. In a script tailored to an environment where echo behaves consistently it is perfectly reasonable to use 'echo', but that's a different story. In the context of git, saying "Here is the thing you should always use instead of echo" is a good thing, in my opinion. Hoping that clarifies, Jonathan -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] test-lib.sh: use printf instead of echo
David Kastrup writes: > Junio C Hamano writes: > >> Jonathan Nieder writes: >> >>> Junio C Hamano wrote: > Uwe Storbeck wrote: >>> >> +printf '%s\n' "$@" | sed -e 's/^/# /' This is wrong, isn't it? Why do we want one line per item here? >>> >>> Yes, Hannes caught the same, too. Sorry for the sloppiness. >>> >>> We currently use "echo" all over the place (e.g., 'echo "$path"' in >>> git-sh-setup), and every time we fix it there is a chance of making >>> mistakes. I wonder if it would make sense to add a helper to make the >>> echo calls easier to replace: >> >> I agree that we would benefit from having a helper to print a single >> line, which we very often do, without having to worry about the >> boilerplate '%s\n' of printf or the portability gotcha of echo. >> >> I am a bit reluctant to name the helper "sane_echo" to declare "echo >> that interprets backslashes in the string is insane", though. > > raw_echo Yeah, but the thing is, this is not even "raw" if you view it from the direction of knowing what "echo" does. That is why I repeated "helper to print a single line", which is a viewpoint from the user side. "We do not care how it is implemented, we just want a single line printed" is what we want to express, which "say" is perfectly in line with. "We use a subset semantics of 'echo' to implement it" is of secondary concern. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] test-lib.sh: use printf instead of echo
Jonathan Nieder writes:
> Junio C Hamano wrote:
>>> Uwe Storbeck wrote:
>
+ printf '%s\n' "$@" | sed -e 's/^/# /'
>>
>> This is wrong, isn't it? Why do we want one line per item here?
>
> Yes, Hannes caught the same, too. Sorry for the sloppiness.
>
> We currently use "echo" all over the place (e.g., 'echo "$path"' in
> git-sh-setup), and every time we fix it there is a chance of making
> mistakes. I wonder if it would make sense to add a helper to make the
> echo calls easier to replace:
I agree that we would benefit from having a helper to print a single
line, which we very often do, without having to worry about the
boilerplate '%s\n' of printf or the portability gotcha of echo.
I am a bit reluctant to name the helper "sane_echo" to declare "echo
that interprets backslashes in the string is insane", though. For
these "print a single line" uses, we are only interested in using a
subset of the features offered by 'echo', but that does not mean the
other features we do not want to trigger in our use is of no use to
any sane person. It very different from "sane_unset" that works
around "unset" on an unset variable that can trigger an error when
nobody sane is interested in that error condition. If somebody is
interested if a variable is not yet set and behave differently,
there are more direct ways to see the "set-ness" of a variable, and
asking "unset" for that information is insane, hence I think the
name "sane_unset" is justified. I do not feel the same way for
"sane_echo".
I would have called it "say" if the name weren't taken.
> -- >8 --
> Subject: git-sh-setup: introduce sane_echo helper
>
> Using 'echo' with arguments that might contain backslashes or "-e" or
> "-n" can produce confusing results that vary from platform to platform
> (e.g., dash always interprets \ escape sequences and echoes "-e"
> verbatim, whereas bash does not interpret \ escapes unless "-e" is
> passed as an argument to echo and suppresses the "-e" from its
> output).
>
> Instead, we should use printf, which is more predictable:
>
> printf '%s\n' "$foo"; # Just prints $foo, on all platforms.
>
> Blindly replacing echo with "printf '%s\n'" would not be good enough
> because that printf prints each argument on its own line. Provide a
> sane_echo helper that prints its arguments, space-delimited, on a
> single line, to make this easier to remember, and tweak 'say'
> and 'die_with_status' to illustrate how it is used.
>
> No functional change intended.
>
> Signed-off-by: Jonathan Nieder
> ---
> git-sh-setup.sh | 8 ++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git i/git-sh-setup.sh w/git-sh-setup.sh
> index 256c89a..f35b5b9 100644
> --- i/git-sh-setup.sh
> +++ w/git-sh-setup.sh
> @@ -43,6 +43,10 @@ git_broken_path_fix () {
>
> # @@BROKEN_PATH_FIX@@
>
> +sane_echo () {
> + printf '%s\n' "$*"
> +}
> +
> die () {
> die_with_status 1 "$@"
> }
> @@ -50,7 +54,7 @@ die () {
> die_with_status () {
> status=$1
> shift
> - printf >&2 '%s\n' "$*"
> + sane_echo >&2 "$*"
> exit "$status"
> }
>
> @@ -59,7 +63,7 @@ GIT_QUIET=
> say () {
> if test -z "$GIT_QUIET"
> then
> - printf '%s\n' "$*"
> + sane_echo "$*"
> fi
> }
>
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Re: [PATCH] test-lib.sh: use printf instead of echo
Junio C Hamano writes: > Jonathan Nieder writes: > >> Junio C Hamano wrote: Uwe Storbeck wrote: >> > + printf '%s\n' "$@" | sed -e 's/^/# /' >>> >>> This is wrong, isn't it? Why do we want one line per item here? >> >> Yes, Hannes caught the same, too. Sorry for the sloppiness. >> >> We currently use "echo" all over the place (e.g., 'echo "$path"' in >> git-sh-setup), and every time we fix it there is a chance of making >> mistakes. I wonder if it would make sense to add a helper to make the >> echo calls easier to replace: > > I agree that we would benefit from having a helper to print a single > line, which we very often do, without having to worry about the > boilerplate '%s\n' of printf or the portability gotcha of echo. > > I am a bit reluctant to name the helper "sane_echo" to declare "echo > that interprets backslashes in the string is insane", though. raw_echo -- David Kastrup -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] test-lib.sh: use printf instead of echo
Junio C Hamano wrote:
>> Uwe Storbeck wrote:
>>> + printf '%s\n' "$@" | sed -e 's/^/# /'
>
> This is wrong, isn't it? Why do we want one line per item here?
Yes, Hannes caught the same, too. Sorry for the sloppiness.
We currently use "echo" all over the place (e.g., 'echo "$path"' in
git-sh-setup), and every time we fix it there is a chance of making
mistakes. I wonder if it would make sense to add a helper to make the
echo calls easier to replace:
-- >8 --
Subject: git-sh-setup: introduce sane_echo helper
Using 'echo' with arguments that might contain backslashes or "-e" or
"-n" can produce confusing results that vary from platform to platform
(e.g., dash always interprets \ escape sequences and echoes "-e"
verbatim, whereas bash does not interpret \ escapes unless "-e" is
passed as an argument to echo and suppresses the "-e" from its
output).
Instead, we should use printf, which is more predictable:
printf '%s\n' "$foo"; # Just prints $foo, on all platforms.
Blindly replacing echo with "printf '%s\n'" would not be good enough
because that printf prints each argument on its own line. Provide a
sane_echo helper that prints its arguments, space-delimited, on a
single line, to make this easier to remember, and tweak 'say'
and 'die_with_status' to illustrate how it is used.
No functional change intended.
Signed-off-by: Jonathan Nieder
---
git-sh-setup.sh | 8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git i/git-sh-setup.sh w/git-sh-setup.sh
index 256c89a..f35b5b9 100644
--- i/git-sh-setup.sh
+++ w/git-sh-setup.sh
@@ -43,6 +43,10 @@ git_broken_path_fix () {
# @@BROKEN_PATH_FIX@@
+sane_echo () {
+ printf '%s\n' "$*"
+}
+
die () {
die_with_status 1 "$@"
}
@@ -50,7 +54,7 @@ die () {
die_with_status () {
status=$1
shift
- printf >&2 '%s\n' "$*"
+ sane_echo >&2 "$*"
exit "$status"
}
@@ -59,7 +63,7 @@ GIT_QUIET=
say () {
if test -z "$GIT_QUIET"
then
- printf '%s\n' "$*"
+ sane_echo "$*"
fi
}
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Re: [PATCH] test-lib.sh: use printf instead of echo
Jonathan Nieder writes:
> Uwe Storbeck wrote:
>
>> Backslash sequences are interpreted as control characters
>> by the echo command of some shells (e.g. dash).
>
> This has bothered me for a while but never enough to do anything about
> it. Thanks for fixing it.
>
>> Signed-off-by: Uwe Storbeck
>
> Reviewed-by: Jonathan Nieder
>
> (patch left unsnipped for reference)
>> ---
>> t/test-lib.sh | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/t/test-lib.sh b/t/test-lib.sh
>> index 1531c24..8209204 100644
>> --- a/t/test-lib.sh
>> +++ b/t/test-lib.sh
>> @@ -277,7 +277,7 @@ error "Test script did not set test_description."
>>
>> if test "$help" = "t"
>> then
>> -echo "$test_description"
>> +printf '%s\n' "$test_description"
>> exit 0
>> fi
>>
>> @@ -328,7 +328,7 @@ test_failure_ () {
>> test_failure=$(($test_failure + 1))
>> say_color error "not ok $test_count - $1"
>> shift
>> -echo "$@" | sed -e 's/^/# /'
>> +printf '%s\n' "$@" | sed -e 's/^/# /'
This is wrong, isn't it? Why do we want one line per item here?
>> test "$immediate" = "" || { GIT_EXIT_OK=t; exit 1; }
>> }
>>
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Re: [PATCH] test-lib.sh: use printf instead of echo
On Mar 15, Johannes Sixt wrote: > > - echo "$@" | sed -e 's/^/# /' > > + printf '%s\n' "$@" | sed -e 's/^/# /' > > This should be > > printf '%s\n' "$*" | sed -e 's/^/# /' Right, that should be $* to always be one argument for the format pattern. Thanks Uwe -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] test-lib.sh: use printf instead of echo
Am 15.03.2014 00:57, schrieb Uwe Storbeck:
> when variables may contain backslash sequences.
>
> Backslash sequences are interpreted as control characters
> by the echo command of some shells (e.g. dash).
>
> Signed-off-by: Uwe Storbeck
> ---
> t/test-lib.sh | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 1531c24..8209204 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -277,7 +277,7 @@ error "Test script did not set test_description."
>
> if test "$help" = "t"
> then
> - echo "$test_description"
> + printf '%s\n' "$test_description"
> exit 0
> fi
>
> @@ -328,7 +328,7 @@ test_failure_ () {
> test_failure=$(($test_failure + 1))
> say_color error "not ok $test_count - $1"
> shift
> - echo "$@" | sed -e 's/^/# /'
> + printf '%s\n' "$@" | sed -e 's/^/# /'
This should be
printf '%s\n' "$*" | sed -e 's/^/# /'
> test "$immediate" = "" || { GIT_EXIT_OK=t; exit 1; }
> }
>
>
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Re: [PATCH] test-lib.sh: use printf instead of echo
Uwe Storbeck wrote:
> Backslash sequences are interpreted as control characters
> by the echo command of some shells (e.g. dash).
This has bothered me for a while but never enough to do anything about
it. Thanks for fixing it.
> Signed-off-by: Uwe Storbeck
Reviewed-by: Jonathan Nieder
(patch left unsnipped for reference)
> ---
> t/test-lib.sh | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 1531c24..8209204 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -277,7 +277,7 @@ error "Test script did not set test_description."
>
> if test "$help" = "t"
> then
> - echo "$test_description"
> + printf '%s\n' "$test_description"
> exit 0
> fi
>
> @@ -328,7 +328,7 @@ test_failure_ () {
> test_failure=$(($test_failure + 1))
> say_color error "not ok $test_count - $1"
> shift
> - echo "$@" | sed -e 's/^/# /'
> + printf '%s\n' "$@" | sed -e 's/^/# /'
> test "$immediate" = "" || { GIT_EXIT_OK=t; exit 1; }
> }
>
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[PATCH] test-lib.sh: use printf instead of echo
when variables may contain backslash sequences.
Backslash sequences are interpreted as control characters
by the echo command of some shells (e.g. dash).
Signed-off-by: Uwe Storbeck
---
t/test-lib.sh | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 1531c24..8209204 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -277,7 +277,7 @@ error "Test script did not set test_description."
if test "$help" = "t"
then
- echo "$test_description"
+ printf '%s\n' "$test_description"
exit 0
fi
@@ -328,7 +328,7 @@ test_failure_ () {
test_failure=$(($test_failure + 1))
say_color error "not ok $test_count - $1"
shift
- echo "$@" | sed -e 's/^/# /'
+ printf '%s\n' "$@" | sed -e 's/^/# /'
test "$immediate" = "" || { GIT_EXIT_OK=t; exit 1; }
}
--
1.9.0
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