threads / patch / 56685

patchhttp-backend: remove a duplicated code branch

Subject: [PATCH] http-backend: remove a duplicated code branch

## tl;dr

9 messages between Oct 11, 2021 and Oct 26, 2021. Diffs are folded; open one to read it.

replies: 8people: 4as markdown or json

Robin Dupret· Oct 11, 2021, 19:25 UTC · lore
---
Hello,
This patch simply factorize two code paths into a single one.

Just wanted to say thanks for this piece of software and all the work you are doing on it ; thank you very much !

I hope I properly followed the contributing guidelines ; if not, sorry.

Have a nice day.
Robin Dupret· Oct 11, 2021, 19:25 UTC · re: Robin Dupret · lore
Signed-off-by: Robin Dupret <robin.dupret@hey.com>
---
 http-backend.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
Show changes to http-backend.c +1 −3
diff --git a/http-backend.c b/http-backend.c
index e7c0eeab23..3d6e2ff17f 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
 	struct child_process cld = CHILD_PROCESS_INIT;
 	ssize_t req_len = get_content_length();
 
-	if (encoding && !strcmp(encoding, "gzip"))
-		gzipped_request = 1;
-	else if (encoding && !strcmp(encoding, "x-gzip"))
+	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
 		gzipped_request = 1;
 
 	if (!user || !*user)

-- 
2.30.1 (Apple Git-130)
Jeff King· Oct 12, 2021, 02:27 UTC · re: Robin Dupret · lore

Re: [PATCH] http-backend: remove a duplicated code branch

On Mon, Oct 11, 2021 at 09:25:46PM +0200, Robin Dupret wrote:
> Signed-off-by: Robin Dupret <robin.dupret@hey.com>

You signed-off, which is good (and necessary for contributing a patch). This is a good place to say "why". Even if it is "because it makes the code more readable", it is good to say that rather than leave readers guessing (though of course people won't necessarily agree ;) ).

Show 17 quoted lines
> ---
>  http-backend.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/http-backend.c b/http-backend.c
> index e7c0eeab23..3d6e2ff17f 100644
> --- a/http-backend.c
> +++ b/http-backend.c
> @@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
>  	struct child_process cld = CHILD_PROCESS_INIT;
>  	ssize_t req_len = get_content_length();
>  
> -	if (encoding && !strcmp(encoding, "gzip"))
> -		gzipped_request = 1;
> -	else if (encoding && !strcmp(encoding, "x-gzip"))
> +	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
>  		gzipped_request = 1;

I think this conversion is correct, and I do find the resulting slightly easier to read. I wondered if the two conditions might have come separately, but no, they were both there in the initial 556cfa3b6d (Smart fetch and push over HTTP: server side, 2009-10-30).

We do frown a bit on making small style changes like this. This kind of churn isn't dramatically improving the quality of the code, and it carries the risk of regression (if there is something subtle that you or the reviewers missed) and creates a maintenance burden (it may conflict with other patches, though I doubt it in this case, and it creates work for reviewers and the maintainer to apply).

So...I dunno. I don't mind it, but it is not a pattern we like to encourage in general. Let's see what Junio thinks.

-Peff
Ævar Arnfjörð Bjarmason· Oct 12, 2021, 09:07 UTC · re: Jeff King · lore

Re: [PATCH] http-backend: remove a duplicated code branch

On Mon, Oct 11 2021, Jeff King wrote:
Show 41 quoted lines
> On Mon, Oct 11, 2021 at 09:25:46PM +0200, Robin Dupret wrote:
>
>> Signed-off-by: Robin Dupret <robin.dupret@hey.com>
>
> You signed-off, which is good (and necessary for contributing a patch).
> This is a good place to say "why". Even if it is "because it makes the
> code more readable", it is good to say that rather than leave readers
> guessing (though of course people won't necessarily agree ;) ).
>
>> ---
>>  http-backend.c | 4 +---
>>  1 file changed, 1 insertion(+), 3 deletions(-)
>> 
>> diff --git a/http-backend.c b/http-backend.c
>> index e7c0eeab23..3d6e2ff17f 100644
>> --- a/http-backend.c
>> +++ b/http-backend.c
>> @@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
>>  	struct child_process cld = CHILD_PROCESS_INIT;
>>  	ssize_t req_len = get_content_length();
>>  
>> -	if (encoding && !strcmp(encoding, "gzip"))
>> -		gzipped_request = 1;
>> -	else if (encoding && !strcmp(encoding, "x-gzip"))
>> +	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
>>  		gzipped_request = 1;
>
> I think this conversion is correct, and I do find the resulting slightly
> easier to read. I wondered if the two conditions might have come
> separately, but no, they were both there in the initial 556cfa3b6d
> (Smart fetch and push over HTTP: server side, 2009-10-30).
>
> We do frown a bit on making small style changes like this. This kind of
> churn isn't dramatically improving the quality of the code, and it
> carries the risk of regression (if there is something subtle that you or
> the reviewers missed) and creates a maintenance burden (it may conflict
> with other patches, though I doubt it in this case, and it creates work
> for reviewers and the maintainer to apply).
>
> So...I dunno. I don't mind it, but it is not a pattern we like to
> encourage in general. Let's see what Junio thinks.

Maybe the existence of this discussion is also why we frown on churn :) But not being able to resist: FWIW I think if this were refactored the below makes more sense (untested etc.):

Because the pattern in that function is to:
 1. Get params via getenv
 2. Provide defaults in case those are NULL
 3. Set resulting structs/variables, use them

The "encoding" and "gzipped_request" are the odd ones out there, this makes them consistent with the rest.

It also has the effect of column-aligning the two strcmps, which along with avoiding indentation is why I general is why I've sometimes used this pattern of:

    if (a && b)
        ;
    else if (a && c)
        ;
Over the obvious simplification of:
    if (a && (b || c))
        ;

Although due to the "if" / "else if" in the pre-image that didn't apply here...

Show changes to http-backend.c +6 −6
diff --git a/http-backend.c b/http-backend.c
index e7c0eeab230..13bc421b4e8 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -462,19 +462,19 @@ static void run_service(const char **argv, int buffer_input)
 	const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 	const char *user = getenv("REMOTE_USER");
 	const char *host = getenv("REMOTE_ADDR");
-	int gzipped_request = 0;
+	int gzipped_request;
 	struct child_process cld = CHILD_PROCESS_INIT;
 	ssize_t req_len = get_content_length();
 
-	if (encoding && !strcmp(encoding, "gzip"))
-		gzipped_request = 1;
-	else if (encoding && !strcmp(encoding, "x-gzip"))
-		gzipped_request = 1;
-
 	if (!user || !*user)
 		user = "anonymous";
 	if (!host || !*host)
 		host = "(none)";
+	if (!encoding)
+		encoding = "";
+
+	gzipped_request = (!strcmp(encoding, "gzip") ||
+			   !strcmp(encoding, "x-gzip"))
 
 	if (!getenv("GIT_COMMITTER_NAME"))
 		strvec_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
Junio C Hamano· Oct 12, 2021, 17:18 UTC · re: Ævar Arnfjörð Bjarmason · lore

Re: [PATCH] http-backend: remove a duplicated code branch

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
Show 27 quoted lines
> diff --git a/http-backend.c b/http-backend.c
> index e7c0eeab230..13bc421b4e8 100644
> --- a/http-backend.c
> +++ b/http-backend.c
> @@ -462,19 +462,19 @@ static void run_service(const char **argv, int buffer_input)
>  	const char *encoding = getenv("HTTP_CONTENT_ENCODING");
>  	const char *user = getenv("REMOTE_USER");
>  	const char *host = getenv("REMOTE_ADDR");
> -	int gzipped_request = 0;
> +	int gzipped_request;
>  	struct child_process cld = CHILD_PROCESS_INIT;
>  	ssize_t req_len = get_content_length();
>  
> -	if (encoding && !strcmp(encoding, "gzip"))
> -		gzipped_request = 1;
> -	else if (encoding && !strcmp(encoding, "x-gzip"))
> -		gzipped_request = 1;
> -
>  	if (!user || !*user)
>  		user = "anonymous";
>  	if (!host || !*host)
>  		host = "(none)";
> +	if (!encoding)
> +		encoding = "";
> +
> +	gzipped_request = (!strcmp(encoding, "gzip") ||
> +			   !strcmp(encoding, "x-gzip"))

In general, I'd frown upon such a conversion. In the the current code, "encoding" might go dead after this point, but we are losing information for no good reason by making !encoding and !*encoding indistinguisable after this point. Compared to that, the rewrite in the patch that started this discussion would be more preferrable.

Thanks.
Junio C Hamano· Oct 12, 2021, 17:15 UTC · re: Jeff King · lore

Re: [PATCH] http-backend: remove a duplicated code branch

Jeff King <peff@peff.net> writes:
Show 28 quoted lines
>> diff --git a/http-backend.c b/http-backend.c
>> index e7c0eeab23..3d6e2ff17f 100644
>> --- a/http-backend.c
>> +++ b/http-backend.c
>> @@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
>>  	struct child_process cld = CHILD_PROCESS_INIT;
>>  	ssize_t req_len = get_content_length();
>>  
>> -	if (encoding && !strcmp(encoding, "gzip"))
>> -		gzipped_request = 1;
>> -	else if (encoding && !strcmp(encoding, "x-gzip"))
>> +	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
>>  		gzipped_request = 1;
>
> I think this conversion is correct, and I do find the resulting slightly
> easier to read. I wondered if the two conditions might have come
> separately, but no, they were both there in the initial 556cfa3b6d
> (Smart fetch and push over HTTP: server side, 2009-10-30).
>
> We do frown a bit on making small style changes like this. This kind of
> churn isn't dramatically improving the quality of the code, and it
> carries the risk of regression (if there is something subtle that you or
> the reviewers missed) and creates a maintenance burden (it may conflict
> with other patches, though I doubt it in this case, and it creates work
> for reviewers and the maintainer to apply).
>
> So...I dunno. I don't mind it, but it is not a pattern we like to
> encourage in general. Let's see what Junio thinks.

This particular conversion is mostly "Meh", although if it were done in this way:

	if (encoding) {
		if (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip"))
			gzipped_request = 1;
	}

the result may be a bit less "meh" by making it easier to adjust the code for other kinds of encoding in the future.

My usual rule of thumb for such a single-hunk clean-up patch that is "obviously not incorrect" is to take it only once or twice per new contributor. At some point, new contributors gain enough experience to know better, at which point I'd start frowning at them.

Thanks.
Robin Dupret· Oct 24, 2021, 16:28 UTC · lore

Try to make reading the computation of the gzipped flag a bit more natural.

Signed-off-by: Robin Dupret <robin.dupret@hey.com>
---
 http-backend.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
Show changes to http-backend.c +1 −3
diff --git a/http-backend.c b/http-backend.c
index e7c0eeab23..3d6e2ff17f 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
 	struct child_process cld = CHILD_PROCESS_INIT;
 	ssize_t req_len = get_content_length();
 
-	if (encoding && !strcmp(encoding, "gzip"))
-		gzipped_request = 1;
-	else if (encoding && !strcmp(encoding, "x-gzip"))
+	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
 		gzipped_request = 1;
 
 	if (!user || !*user)

-- 
2.30.1 (Apple Git-130)
Junio C Hamano· Oct 25, 2021, 15:55 UTC · re: Robin Dupret · lore

Re: [PATCH] http-backend: remove a duplicated code branch

Robin Dupret <robin.dupret@gmail.com> writes:
> Try to make reading the computation of the gzipped flag a bit more
> natural.
... and did you succeed? ;-)

We are all imperfect human and anything we do is merely "trying to", so let's not say "try to", unless the change is so involved that it is hard to judge if the result has succeeded in trying.

Did you mean to send the same patch text (but with an updated log message)? Just making sure.

Thanks; will queue.
Show 20 quoted lines
> Signed-off-by: Robin Dupret <robin.dupret@hey.com>
> ---
>  http-backend.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/http-backend.c b/http-backend.c
> index e7c0eeab23..3d6e2ff17f 100644
> --- a/http-backend.c
> +++ b/http-backend.c
> @@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
>  	struct child_process cld = CHILD_PROCESS_INIT;
>  	ssize_t req_len = get_content_length();
>  
> -	if (encoding && !strcmp(encoding, "gzip"))
> -		gzipped_request = 1;
> -	else if (encoding && !strcmp(encoding, "x-gzip"))
> +	if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
>  		gzipped_request = 1;
>  
>  	if (!user || !*user)
Robin Dupret· Oct 26, 2021, 19:04 UTC · re: Junio C Hamano · lore

Re: [PATCH] http-backend: remove a duplicated code branch

> Did you mean to send the same patch text (but with an updated log
> message)?  Just making sure.
Yes, exactly.
> We are all imperfect human and anything we do is merely "trying to"

Fair point. :-) Do you want me to resend the patch without this part or is it ok ?

Thank you !
Le lun. 25 oct. 2021 à 17:55, Junio C Hamano <gitster@pobox.com> a écrit :
Show 37 quoted lines
>
> Robin Dupret <robin.dupret@gmail.com> writes:
>
> > Try to make reading the computation of the gzipped flag a bit more
> > natural.
>
> ... and did you succeed? ;-)
>
> We are all imperfect human and anything we do is merely "trying to",
> so let's not say "try to", unless the change is so involved that it
> is hard to judge if the result has succeeded in trying.
>
> Did you mean to send the same patch text (but with an updated log
> message)?  Just making sure.
>
> Thanks; will queue.
>
> > Signed-off-by: Robin Dupret <robin.dupret@hey.com>
> > ---
> >  http-backend.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/http-backend.c b/http-backend.c
> > index e7c0eeab23..3d6e2ff17f 100644
> > --- a/http-backend.c
> > +++ b/http-backend.c
> > @@ -466,9 +466,7 @@ static void run_service(const char **argv, int buffer_input)
> >       struct child_process cld = CHILD_PROCESS_INIT;
> >       ssize_t req_len = get_content_length();
> >
> > -     if (encoding && !strcmp(encoding, "gzip"))
> > -             gzipped_request = 1;
> > -     else if (encoding && !strcmp(encoding, "x-gzip"))
> > +     if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
> >               gzipped_request = 1;
> >
> >       if (!user || !*user)

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