[PATCH] pager: set LV=-c alongside LESS=FRSX

[PATCH] pager: set LV=-c alongside LESS=FRSX

[Jonathan Nieder]

On systems with lv configured as the preferred pager (i.e.,
DEFAULT_PAGER=lv at build time, or PAGER=lv exported in the
environment) git commands that use color show control codes instead of
color in the pager:

	$ git diff
	^[[1mdiff --git a/.mailfilter b/.mailfilter^[[m
	^[[1mindex aa4f0b2..17e113e 100644^[[m
	^[[1m--- a/.mailfilter^[[m
	^[[1m+++ b/.mailfilter^[[m
	^[[36m@@ -1,11 +1,58 @@^[[m

"less" avoids this problem because git uses the LESS environment
variable to pass the -R option ('output ANSI color escapes in raw
form') by default.  Use the LV environment variable to pass 'lv' the
-c option ('allow ANSI escape sequences for text decoration / color')
to fix it for lv, too.

Noticed when the default value for color.ui flipped to 'auto' in
v1.8.4-rc0~36^2~1 (2013-06-10).

Reported-by: Olaf Meeuwissen <olaf.meeuwissen@avasys.jp>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Olaf Meeuwissen wrote[1]:

> Yes, it's called LV and documented in the lv(1) manual page.  Simply
> search for 'env' ;-)

Ah, thanks.  How about this patch?

[1] http://bugs.debian.org/730527

 Documentation/config.txt |  4 ++++
 git-sh-setup.sh          |  3 ++-
 pager.c                  | 11 +++++++++--
 perl/Git/SVN/Log.pm      |  1 +
 t/t7006-pager.sh         | 12 ++++++++++++
 5 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index a405806..ed59853 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -567,6 +567,10 @@ be passed to the shell by Git, which will translate the final
 command to `LESS=FRSX less -+S`. The environment tells the command
 to set the `S` option to chop long lines but the command line
 resets it to the default to fold long lines.
++
+Likewise, when the `LV` environment variable is unset, Git sets it
+to `-c`.  You can override this setting by exporting `LV` with
+another value or setting `core.pager` to `lv +c`.
 
 core.whitespace::
 	A comma separated list of common whitespace problems to
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 190a539..fffa3c7 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -159,7 +159,8 @@ git_pager() {
 		GIT_PAGER=cat
 	fi
 	: ${LESS=-FRSX}
-	export LESS
+	: ${LV=-c}
+	export LESS LV
 
 	eval "$GIT_PAGER" '"$@"'
 }
diff --git a/pager.c b/pager.c
index 345b0bc..0cc75a8 100644
--- a/pager.c
+++ b/pager.c
@@ -80,8 +80,15 @@ void setup_pager(void)
 	pager_process.use_shell = 1;
 	pager_process.argv = pager_argv;
 	pager_process.in = -1;
-	if (!getenv("LESS")) {
-		static const char *env[] = { "LESS=FRSX", NULL };
+	if (!getenv("LESS") || !getenv("LV")) {
+		static const char *env[3];
+		int i = 0;
+
+		if (!getenv("LESS"))
+			env[i++] = "LESS=FRSX";
+		if (!getenv("LV"))
+			env[i++] = "LV=-c";
+		env[i] = NULL;
 		pager_process.env = env;
 	}
 	if (start_command(&pager_process))
diff --git a/perl/Git/SVN/Log.pm b/perl/Git/SVN/Log.pm
index 3f8350a..34f2869 100644
--- a/perl/Git/SVN/Log.pm
+++ b/perl/Git/SVN/Log.pm
@@ -117,6 +117,7 @@ sub run_pager {
 	}
 	open STDIN, '<&', $rfd or fatal "Can't redirect stdin: $!";
 	$ENV{LESS} ||= 'FRSX';
+	$ENV{LV} ||= '-c';
 	exec $pager or fatal "Can't run pager: $! ($pager)";
 }
 
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index ff25908..7fe3367 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -37,6 +37,18 @@ test_expect_failure TTY 'pager runs from subdir' '
 	test_cmp expected actual
 '
 
+test_expect_success TTY 'LESS and LV envvars are set for pagination' '
+	(
+		sane_unset LESS LV &&
+		PAGER="env >pager-env.out" &&
+		export PAGER &&
+
+		test_terminal git log
+	) &&
+	grep ^LESS= pager-env.out &&
+	grep ^LV= pager-env.out
+'
+
 test_expect_success TTY 'some commands do not use a pager' '
 	rm -f paginated.out &&
 	test_terminal git rev-list HEAD &&
-- 
1.8.5.1

Re: [PATCH] pager: set LV=-c alongside LESS=FRSX

[Olaf Meeuwissen]

Jonathan Nieder writes:

> On systems with lv configured as the preferred pager (i.e.,
> DEFAULT_PAGER=lv at build time, or PAGER=lv exported in the
> environment) git commands that use color show control codes instead of
> color in the pager:
>
> 	$ git diff
> 	^[[1mdiff --git a/.mailfilter b/.mailfilter^[[m
> 	^[[1mindex aa4f0b2..17e113e 100644^[[m
> 	^[[1m--- a/.mailfilter^[[m
> 	^[[1m+++ b/.mailfilter^[[m
> 	^[[36m@@ -1,11 +1,58 @@^[[m
>
> "less" avoids this problem because git uses the LESS environment
> variable to pass the -R option ('output ANSI color escapes in raw
> form') by default.  Use the LV environment variable to pass 'lv' the
> -c option ('allow ANSI escape sequences for text decoration / color')
> to fix it for lv, too.
>
> Noticed when the default value for color.ui flipped to 'auto' in
> v1.8.4-rc0~36^2~1 (2013-06-10).
>
> Reported-by: Olaf Meeuwissen <olaf.meeuwissen@avasys.jp>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
> Olaf Meeuwissen wrote[1]:
>
>> Yes, it's called LV and documented in the lv(1) manual page.  Simply
>> search for 'env' ;-)
>
> Ah, thanks.  How about this patch?

I'm not qualified to judge the appropriateness of your patch, but if it
achieves activating the -c option of lv when that is the pager in effect
then that should work for the bulk of the use cases, I'd think.

> [1] http://bugs.debian.org/730527
>
>  Documentation/config.txt |  4 ++++
>  git-sh-setup.sh          |  3 ++-
>  pager.c                  | 11 +++++++++--
>  perl/Git/SVN/Log.pm      |  1 +
>  t/t7006-pager.sh         | 12 ++++++++++++
>  5 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index a405806..ed59853 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -567,6 +567,10 @@ be passed to the shell by Git, which will translate the final
>  command to `LESS=FRSX less -+S`. The environment tells the command
>  to set the `S` option to chop long lines but the command line
>  resets it to the default to fold long lines.
> ++
> +Likewise, when the `LV` environment variable is unset, Git sets it
> +to `-c`.  You can override this setting by exporting `LV` with
> +another value or setting `core.pager` to `lv +c`.
>  
>  core.whitespace::
>  	A comma separated list of common whitespace problems to
> diff --git a/git-sh-setup.sh b/git-sh-setup.sh
> index 190a539..fffa3c7 100644
> --- a/git-sh-setup.sh
> +++ b/git-sh-setup.sh
> @@ -159,7 +159,8 @@ git_pager() {
>  		GIT_PAGER=cat
>  	fi
>  	: ${LESS=-FRSX}
> -	export LESS
> +	: ${LV=-c}
> +	export LESS LV
>  
>  	eval "$GIT_PAGER" '"$@"'
>  }
> diff --git a/pager.c b/pager.c
> index 345b0bc..0cc75a8 100644
> --- a/pager.c
> +++ b/pager.c
> @@ -80,8 +80,15 @@ void setup_pager(void)
>  	pager_process.use_shell = 1;
>  	pager_process.argv = pager_argv;
>  	pager_process.in = -1;
> -	if (!getenv("LESS")) {
> -		static const char *env[] = { "LESS=FRSX", NULL };
> +	if (!getenv("LESS") || !getenv("LV")) {
> +		static const char *env[3];
> +		int i = 0;
> +
> +		if (!getenv("LESS"))
> +			env[i++] = "LESS=FRSX";
> +		if (!getenv("LV"))
> +			env[i++] = "LV=-c";
> +		env[i] = NULL;
>  		pager_process.env = env;
>  	}
>  	if (start_command(&pager_process))
> diff --git a/perl/Git/SVN/Log.pm b/perl/Git/SVN/Log.pm
> index 3f8350a..34f2869 100644
> --- a/perl/Git/SVN/Log.pm
> +++ b/perl/Git/SVN/Log.pm
> @@ -117,6 +117,7 @@ sub run_pager {
>  	}
>  	open STDIN, '<&', $rfd or fatal "Can't redirect stdin: $!";
>  	$ENV{LESS} ||= 'FRSX';
> +	$ENV{LV} ||= '-c';
>  	exec $pager or fatal "Can't run pager: $! ($pager)";
>  }
>  
> diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
> index ff25908..7fe3367 100755
> --- a/t/t7006-pager.sh
> +++ b/t/t7006-pager.sh
> @@ -37,6 +37,18 @@ test_expect_failure TTY 'pager runs from subdir' '
>  	test_cmp expected actual
>  '
>  
> +test_expect_success TTY 'LESS and LV envvars are set for pagination' '
> +	(
> +		sane_unset LESS LV &&
> +		PAGER="env >pager-env.out" &&
> +		export PAGER &&
> +
> +		test_terminal git log
> +	) &&
> +	grep ^LESS= pager-env.out &&
> +	grep ^LV= pager-env.out
> +'
> +
>  test_expect_success TTY 'some commands do not use a pager' '
>  	rm -f paginated.out &&
>  	test_terminal git rev-list HEAD &&

Hope this helps,
-- 
Olaf Meeuwissen, LPIC-2           FLOSS Engineer -- AVASYS CORPORATION
FSF Associate Member #1962               Help support software freedom
                 http://www.fsf.org/jf?referrer=1962

Re: [PATCH] pager: set LV=-c alongside LESS=FRSX

[Junio C Hamano]

Jonathan Nieder <jrnieder@gmail.com> writes:

> On systems with lv configured as the preferred pager (i.e.,
> DEFAULT_PAGER=lv at build time, or PAGER=lv exported in the
> environment) git commands that use color show control codes instead of
> color in the pager:
>
> 	$ git diff
> 	^[[1mdiff --git a/.mailfilter b/.mailfilter^[[m
> 	^[[1mindex aa4f0b2..17e113e 100644^[[m
> 	^[[1m--- a/.mailfilter^[[m
> 	^[[1m+++ b/.mailfilter^[[m
> 	^[[36m@@ -1,11 +1,58 @@^[[m
>
> "less" avoids this problem because git uses the LESS environment
> variable to pass the -R option ('output ANSI color escapes in raw
> form') by default.  Use the LV environment variable to pass 'lv' the
> -c option ('allow ANSI escape sequences for text decoration / color')
> to fix it for lv, too.
>
> Noticed when the default value for color.ui flipped to 'auto' in
> v1.8.4-rc0~36^2~1 (2013-06-10).
>
> Reported-by: Olaf Meeuwissen <olaf.meeuwissen@avasys.jp>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
> Olaf Meeuwissen wrote[1]:
>
>> Yes, it's called LV and documented in the lv(1) manual page.  Simply
>> search for 'env' ;-)
>
> Ah, thanks.  How about this patch?
>
> [1] http://bugs.debian.org/730527

Looks good; though I have to wonder two (and a half) things:

 - Scripted Porcelains get LESS=-FRSX while C Porcelains get
   LESS=FRSX as the default (the leading dash being the
   difference), which looks somewhat inconsistent.  Not a new
   problem, though.

 - Can we generalize this a bit so that a builder can pass a list
   of var=val pairs and demote the existing LESS=FRSX to just a
   canned setting of such a mechanism?

 - Can such a code be reused to make this into a runtime setting,
   even?  Would it be worth the complexity?

Thanks.

>  Documentation/config.txt |  4 ++++
>  git-sh-setup.sh          |  3 ++-
>  pager.c                  | 11 +++++++++--
>  perl/Git/SVN/Log.pm      |  1 +
>  t/t7006-pager.sh         | 12 ++++++++++++
>  5 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index a405806..ed59853 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -567,6 +567,10 @@ be passed to the shell by Git, which will translate the final
>  command to `LESS=FRSX less -+S`. The environment tells the command
>  to set the `S` option to chop long lines but the command line
>  resets it to the default to fold long lines.
> ++
> +Likewise, when the `LV` environment variable is unset, Git sets it
> +to `-c`.  You can override this setting by exporting `LV` with
> +another value or setting `core.pager` to `lv +c`.
>  
>  core.whitespace::
>  	A comma separated list of common whitespace problems to
> diff --git a/git-sh-setup.sh b/git-sh-setup.sh
> index 190a539..fffa3c7 100644
> --- a/git-sh-setup.sh
> +++ b/git-sh-setup.sh
> @@ -159,7 +159,8 @@ git_pager() {
>  		GIT_PAGER=cat
>  	fi
>  	: ${LESS=-FRSX}
> -	export LESS
> +	: ${LV=-c}
> +	export LESS LV
>  
>  	eval "$GIT_PAGER" '"$@"'
>  }
> diff --git a/pager.c b/pager.c
> index 345b0bc..0cc75a8 100644
> --- a/pager.c
> +++ b/pager.c
> @@ -80,8 +80,15 @@ void setup_pager(void)
>  	pager_process.use_shell = 1;
>  	pager_process.argv = pager_argv;
>  	pager_process.in = -1;
> -	if (!getenv("LESS")) {
> -		static const char *env[] = { "LESS=FRSX", NULL };
> +	if (!getenv("LESS") || !getenv("LV")) {
> +		static const char *env[3];
> +		int i = 0;
> +
> +		if (!getenv("LESS"))
> +			env[i++] = "LESS=FRSX";
> +		if (!getenv("LV"))
> +			env[i++] = "LV=-c";
> +		env[i] = NULL;
>  		pager_process.env = env;
>  	}
>  	if (start_command(&pager_process))
> diff --git a/perl/Git/SVN/Log.pm b/perl/Git/SVN/Log.pm
> index 3f8350a..34f2869 100644
> --- a/perl/Git/SVN/Log.pm
> +++ b/perl/Git/SVN/Log.pm
> @@ -117,6 +117,7 @@ sub run_pager {
>  	}
>  	open STDIN, '<&', $rfd or fatal "Can't redirect stdin: $!";
>  	$ENV{LESS} ||= 'FRSX';
> +	$ENV{LV} ||= '-c';
>  	exec $pager or fatal "Can't run pager: $! ($pager)";
>  }
>  
> diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
> index ff25908..7fe3367 100755
> --- a/t/t7006-pager.sh
> +++ b/t/t7006-pager.sh
> @@ -37,6 +37,18 @@ test_expect_failure TTY 'pager runs from subdir' '
>  	test_cmp expected actual
>  '
>  
> +test_expect_success TTY 'LESS and LV envvars are set for pagination' '
> +	(
> +		sane_unset LESS LV &&
> +		PAGER="env >pager-env.out" &&
> +		export PAGER &&
> +
> +		test_terminal git log
> +	) &&
> +	grep ^LESS= pager-env.out &&
> +	grep ^LV= pager-env.out
> +'
> +
>  test_expect_success TTY 'some commands do not use a pager' '
>  	rm -f paginated.out &&
>  	test_terminal git rev-list HEAD &&

Re: [PATCH] pager: set LV=-c alongside LESS=FRSX

[Andreas Schwab]

Junio C Hamano <gitster@pobox.com> writes:

>  - Scripted Porcelains get LESS=-FRSX while C Porcelains get
>    LESS=FRSX as the default (the leading dash being the
>    difference), which looks somewhat inconsistent.  Not a new
>    problem, though.

Even the less manpage is inconsistent about whether $LESS should start
with a dash (there are examples with and without it).
Implementation-wise, less uses the same function to process an option
argument (including the leading dash) and the value of $LESS, so the
form with the leading dash is probably preferred.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [PATCH] pager: set LV=-c alongside LESS=FRSX

[Anders Kaseorg]

On 01/06/2014 09:14 PM, Jonathan Nieder wrote:
> +test_expect_success TTY 'LESS and LV envvars are set for pagination' '
> +	(
> +		sane_unset LESS LV &&
> +		PAGER="env >pager-env.out" &&
> +		export PAGER &&
> +
> +		test_terminal git log
> +	) &&
> +	grep ^LESS= pager-env.out &&
> +	grep ^LV= pager-env.out
> +'
> +

On the Ubuntu PPA builders, I’m seeing this new test fail with SIGPIPE 
about half the time:

died of signal 13 at /build/buildd/git-1.9~rc1/t/test-terminal.perl line 33.
not ok 6 - LESS and LV envvars are set for pagination

Although the test seems to work locally for me, I can reproduce a 
similar failure just by running

$ GIT_PAGER='env >pager-env.out' ./test-terminal.perl git log
died of signal 13 at ./test-terminal.perl line 33.

Anders

[PATCH jn/pager-lv-default-env] pager test: make fake pager consume all its input

[Jonathan Nieder]

Otherwise there is a race: if 'git log' finishes writing before the
pager terminates and closes the pipe, all is well, and if the pager
finishes quickly enough then 'git log' terminates with SIGPIPE.

 died of signal 13 at /build/buildd/git-1.9~rc1/t/test-terminal.perl line 33.
 not ok 6 - LESS and LV envvars are set for pagination

Noticed on Ubuntu PPA builders, where the race was lost about half the
time.  Compare v1.7.0.2~6^2 (tests: Fix race condition in t7006-pager,
2010-02-22).

Reported-by: Anders Kaseorg <andersk@MIT.EDU>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Anders Kaseorg wrote:
> On 01/06/2014 09:14 PM, Jonathan Nieder wrote:

>> +		PAGER="env >pager-env.out" &&
>> +		export PAGER &&
>> +
>> +		test_terminal git log
[...]
> On the Ubuntu PPA builders, I’m seeing this new test fail with
> SIGPIPE about half the time:
>
> died of signal 13 at /build/buildd/git-1.9~rc1/t/test-terminal.perl line 33.
> not ok 6 - LESS and LV envvars are set for pagination

Good catch.  Sorry for the trouble.

 t/t7006-pager.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 7fe3367..b9365b4 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -40,7 +40,7 @@ test_expect_failure TTY 'pager runs from subdir' '
 test_expect_success TTY 'LESS and LV envvars are set for pagination' '
 	(
 		sane_unset LESS LV &&
-		PAGER="env >pager-env.out" &&
+		PAGER="env >pager-env.out; wc" &&
 		export PAGER &&
 
 		test_terminal git log
-- 
1.9.rc1.175.g0b1dcb5

Re: [PATCH jn/pager-lv-default-env] pager test: make fake pager consume all its input

[Junio C Hamano]

Jonathan Nieder <jrnieder@gmail.com> writes:

> Otherwise there is a race: if 'git log' finishes writing before the
> pager terminates and closes the pipe, all is well, and if the pager
> finishes quickly enough then 'git log' terminates with SIGPIPE.
>
>  died of signal 13 at /build/buildd/git-1.9~rc1/t/test-terminal.perl line 33.
>  not ok 6 - LESS and LV envvars are set for pagination
>
> Noticed on Ubuntu PPA builders, where the race was lost about half the
> time.  Compare v1.7.0.2~6^2 (tests: Fix race condition in t7006-pager,
> 2010-02-22).
>
> Reported-by: Anders Kaseorg <andersk@MIT.EDU>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---

Thanks.  The use of "wc" looks cute (I would have used "cat").

> Anders Kaseorg wrote:
>> On 01/06/2014 09:14 PM, Jonathan Nieder wrote:
>
>>> +		PAGER="env >pager-env.out" &&
>>> +		export PAGER &&
>>> +
>>> +		test_terminal git log
> [...]
>> On the Ubuntu PPA builders, I’m seeing this new test fail with
>> SIGPIPE about half the time:
>>
>> died of signal 13 at /build/buildd/git-1.9~rc1/t/test-terminal.perl line 33.
>> not ok 6 - LESS and LV envvars are set for pagination
>
> Good catch.  Sorry for the trouble.
>
>  t/t7006-pager.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
> index 7fe3367..b9365b4 100755
> --- a/t/t7006-pager.sh
> +++ b/t/t7006-pager.sh
> @@ -40,7 +40,7 @@ test_expect_failure TTY 'pager runs from subdir' '
>  test_expect_success TTY 'LESS and LV envvars are set for pagination' '
>  	(
>  		sane_unset LESS LV &&
> -		PAGER="env >pager-env.out" &&
> +		PAGER="env >pager-env.out; wc" &&
>  		export PAGER &&
>  
>  		test_terminal git log