threads / patch / 44176

patch, 2 partsuse strbuf_addstr() instead of strbuf_addf() with "%s", part 2

Subject: [PATCH 1/2] use strbuf_addstr() instead of strbuf_addf() with "%s", part 2

## tl;dr

6 messages between Sep 27, 2016 and Oct 7, 2016. Diffs are folded; open one to read it.

replies: 5people: 3as markdown or json

René Scharfe· Sep 27, 2016, 19:08 UTC · lore

Replace uses of strbuf_addf() for adding strings with more lightweight strbuf_addstr() calls. This is shorter and makes the intent clearer.

bc57b9c0cc5a123365a922fa1831177e3fd607ed already converted three cases, this patch covers two more.

A semantic patch for Coccinelle is included for easier checking for new cases that might be introduced in the future.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 builtin/submodule--helper.c     | 2 +-
 contrib/coccinelle/strbuf.cocci | 6 ++++++
 submodule.c                     | 2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)
Show changes to 3 files +8 −2

builtin/submodule--helper.c, contrib/coccinelle/strbuf.cocci, submodule.c

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e3fdc0a..444ec06 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -753,7 +753,7 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		if (suc->recursive_prefix)
 			strbuf_addf(&sb, "%s/%s", suc->recursive_prefix, ce->name);
 		else
-			strbuf_addf(&sb, "%s", ce->name);
+			strbuf_addstr(&sb, ce->name);
 		strbuf_addf(out, _("Skipping unmerged submodule %s"), sb.buf);
 		strbuf_addch(out, '\n');
 		goto cleanup;
diff --git a/contrib/coccinelle/strbuf.cocci b/contrib/coccinelle/strbuf.cocci
index 7932d48..4b7553f 100644
--- a/contrib/coccinelle/strbuf.cocci
+++ b/contrib/coccinelle/strbuf.cocci
@@ -3,3 +3,9 @@ expression E1, E2;
 @@
 - strbuf_addf(E1, E2);
 + strbuf_addstr(E1, E2);
+
+@@
+expression E1, E2;
+@@
+- strbuf_addf(E1, "%s", E2);
++ strbuf_addstr(E1, E2);
diff --git a/submodule.c b/submodule.c
index 0ef2ff4..dcc5ce3 100644
--- a/submodule.c
+++ b/submodule.c
@@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
 			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
 	if (!fast_backward && !fast_forward)
 		strbuf_addch(&sb, '.');
-	strbuf_addf(&sb, "%s", find_unique_abbrev(two->hash, DEFAULT_ABBREV));
+	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
 	if (message)
 		strbuf_addf(&sb, " %s%s\n", message, reset);
 	else

-- 
2.10.0
René Scharfe· Sep 27, 2016, 19:11 UTC · re: René Scharfe · lore

[PATCH 2/2] use strbuf_add_unique_abbrev() for adding short hashes, part 2

Call strbuf_add_unique_abbrev() to add abbreviated hashes to strbufs instead of taking detours through find_unique_abbrev() and its static buffer. This is shorter and a bit more efficient.

1eb47f167d65d1d305b9c196a1bb40eb96117cb1 already converted six cases, this patch covers three more.

A semantic patch for Coccinelle is included for easier checking for new cases that might be introduced in the future.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 contrib/coccinelle/strbuf.cocci | 6 ++++++
 diff.c                          | 2 +-
 submodule.c                     | 2 +-
 wt-status.c                     | 3 +--
 4 files changed, 9 insertions(+), 4 deletions(-)
Show changes to 4 files +9 −4

contrib/coccinelle/strbuf.cocci, diff.c, submodule.c, wt-status.c

diff --git a/contrib/coccinelle/strbuf.cocci b/contrib/coccinelle/strbuf.cocci
index 4b7553f..1e24298 100644
--- a/contrib/coccinelle/strbuf.cocci
+++ b/contrib/coccinelle/strbuf.cocci
@@ -9,3 +9,9 @@ expression E1, E2;
 @@
 - strbuf_addf(E1, "%s", E2);
 + strbuf_addstr(E1, E2);
+
+@@
+expression E1, E2, E3;
+@@
+- strbuf_addstr(E1, find_unique_abbrev(E2, E3));
++ strbuf_add_unique_abbrev(E1, E2, E3);
diff --git a/diff.c b/diff.c
index a178ed3..be11e4e 100644
--- a/diff.c
+++ b/diff.c
@@ -3109,7 +3109,7 @@ static void fill_metainfo(struct strbuf *msg,
 		}
 		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
 			    find_unique_abbrev(one->oid.hash, abbrev));
-		strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
+		strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
 		if (one->mode == two->mode)
 			strbuf_addf(msg, " %06o", one->mode);
 		strbuf_addf(msg, "%s\n", reset);
diff --git a/submodule.c b/submodule.c
index dcc5ce3..8cf40ea 100644
--- a/submodule.c
+++ b/submodule.c
@@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
 			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
 	if (!fast_backward && !fast_forward)
 		strbuf_addch(&sb, '.');
-	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
+	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
 	if (message)
 		strbuf_addf(&sb, " %s%s\n", message, reset);
 	else
diff --git a/wt-status.c b/wt-status.c
index 9628c1d..99d1b0a 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -1383,8 +1383,7 @@ static int grab_1st_switch(unsigned char *osha1, unsigned char *nsha1,
 	if (!strcmp(cb->buf.buf, "HEAD")) {
 		/* HEAD is relative. Resolve it to the right reflog entry. */
 		strbuf_reset(&cb->buf);
-		strbuf_addstr(&cb->buf,
-			      find_unique_abbrev(nsha1, DEFAULT_ABBREV));
+		strbuf_add_unique_abbrev(&cb->buf, nsha1, DEFAULT_ABBREV);
 	}
 	return 1;
 }

-- 
2.10.0
Junio C Hamano· Sep 27, 2016, 20:28 UTC · re: René Scharfe · lore

Re: [PATCH 2/2] use strbuf_add_unique_abbrev() for adding short hashes, part 2

René Scharfe <l.s.r@web.de> writes:
Show 10 quoted lines
> diff --git a/diff.c b/diff.c
> index a178ed3..be11e4e 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -3109,7 +3109,7 @@ static void fill_metainfo(struct strbuf *msg,
>  		}
>  		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
>  			    find_unique_abbrev(one->oid.hash, abbrev));
> -		strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
> +		strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
OK.
Show 10 quoted lines
> diff --git a/submodule.c b/submodule.c
> index dcc5ce3..8cf40ea 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
>  			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
>  	if (!fast_backward && !fast_forward)
>  		strbuf_addch(&sb, '.');
> -	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
> +	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
I wonder how could this change come out of this definition:
    @@
    expression E1, E2, E3;
    @@
    - strbuf_addstr(E1, find_unique_abbrev(E2, E3));
    + strbuf_add_unique_abbrev(E1, E2, E3);
René Scharfe· Sep 27, 2016, 20:59 UTC · re: Junio C Hamano · lore

Re: [PATCH 2/2] use strbuf_add_unique_abbrev() for adding short hashes, part 2

Am 27.09.2016 um 22:28 schrieb Junio C Hamano:
Show 19 quoted lines
> René Scharfe <l.s.r@web.de> writes:
>> diff --git a/submodule.c b/submodule.c
>> index dcc5ce3..8cf40ea 100644
>> --- a/submodule.c
>> +++ b/submodule.c
>> @@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
>>  			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
>>  	if (!fast_backward && !fast_forward)
>>  		strbuf_addch(&sb, '.');
>> -	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
>> +	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
> 
> I wonder how could this change come out of this definition:
> 
>     @@
>     expression E1, E2, E3;
>     @@
>     - strbuf_addstr(E1, find_unique_abbrev(E2, E3));
>     + strbuf_add_unique_abbrev(E1, E2, E3);

Impossible. I added "->hash" manually during a rebase (merging a0d12c44, wrongly). Good catch, thanks!

Seeing proof of skipping compile-testing I wonder what else I do forget in my daily life. :-| I'll better go to sleep now..

Fixup patch, generated by reverting the diff, re-adding the
semantic patch and using coccicheck; compiles and survives make
test:
---
 submodule.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to submodule.c +1 −1
diff --git a/submodule.c b/submodule.c
index 8cf40ea..bb06b60 100644
--- a/submodule.c
+++ b/submodule.c
@@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
 			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
 	if (!fast_backward && !fast_forward)
 		strbuf_addch(&sb, '.');
-	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
+	strbuf_add_unique_abbrev(&sb, two->hash, DEFAULT_ABBREV);
 	if (message)
 		strbuf_addf(&sb, " %s%s\n", message, reset);
 	else

-- 
2.10.0
Jeff King· Oct 7, 2016, 00:46 UTC · re: René Scharfe · lore

Re: [PATCH 2/2] use strbuf_add_unique_abbrev() for adding short hashes, part 2

On Tue, Sep 27, 2016 at 09:11:58PM +0200, René Scharfe wrote:
Show 17 quoted lines
> Call strbuf_add_unique_abbrev() to add abbreviated hashes to strbufs
> instead of taking detours through find_unique_abbrev() and its static
> buffer.  This is shorter and a bit more efficient.
> [...]
> diff --git a/diff.c b/diff.c
> index a178ed3..be11e4e 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -3109,7 +3109,7 @@ static void fill_metainfo(struct strbuf *msg,
>  		}
>  		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
>  			    find_unique_abbrev(one->oid.hash, abbrev));
> -		strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
> +		strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
>  		if (one->mode == two->mode)
>  			strbuf_addf(msg, " %06o", one->mode);
>  		strbuf_addf(msg, "%s\n", reset);

This one is an interesting case, and maybe a good example of why blind coccinelle usage can have some pitfalls. :)

We get rid of the strbuf_addstr(), but notice that we leave untouched the find_unique_abbrev() call immediately above. There was a symmetry to the two that has been lost.

Probably either:
  strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set
	find_unique_abbrev(one->oid.hash, abbrev),
	find_unique_abbrev(two->oid.hash, abbrev));
or:
  strbuf_addf(msg, "%s%sindex ", line_prefix, set);
  strbuf_add_unique_abbrev(msg, one->oid.hash, abbrev);
  strbuf_addstr(msg, "..");
  strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);

would be a more appropriate refactoring. The problem is in the original patch (which also lacks symmetry; either this predates the multi-buffer find_unique_abbrev, or the original author didn't know about it), but I think your refactor makes it slightly worse.

I noticed because I have another series which touches these lines, and it wants to symmetrically swap out find_unique_abbrev for something else. :) I don't think it's a big enough deal to switch now (and I've already rebased my series which will touch these lines), but I wanted to mention it as a thing to watch out for as we do more of these kinds of automated transformations.

Show 8 quoted lines
> --- a/submodule.c
> +++ b/submodule.c
> @@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
>  			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
>  	if (!fast_backward && !fast_forward)
>  		strbuf_addch(&sb, '.');
> -	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
> +	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
This one is a similar situation, I think.
-Peff
René Scharfe· Oct 7, 2016, 20:45 UTC · re: Jeff King · lore

Re: [PATCH 2/2] use strbuf_add_unique_abbrev() for adding short hashes, part 2

Am 07.10.2016 um 02:46 schrieb Jeff King:
Show 22 quoted lines
> On Tue, Sep 27, 2016 at 09:11:58PM +0200, René Scharfe wrote:
>
>> Call strbuf_add_unique_abbrev() to add abbreviated hashes to strbufs
>> instead of taking detours through find_unique_abbrev() and its static
>> buffer.  This is shorter and a bit more efficient.
>> [...]
>> diff --git a/diff.c b/diff.c
>> index a178ed3..be11e4e 100644
>> --- a/diff.c
>> +++ b/diff.c
>> @@ -3109,7 +3109,7 @@ static void fill_metainfo(struct strbuf *msg,
>>  		}
>>  		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
>>  			    find_unique_abbrev(one->oid.hash, abbrev));
>> -		strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
>> +		strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
>>  		if (one->mode == two->mode)
>>  			strbuf_addf(msg, " %06o", one->mode);
>>  		strbuf_addf(msg, "%s\n", reset);
>
> This one is an interesting case, and maybe a good example of why blind
> coccinelle usage can have some pitfalls. :)

Thank you for paying attention. :) In general I agree that the surrounding code of such changes should be checked; the issue at hand could be part of a bigger problem.

Show 21 quoted lines
> We get rid of the strbuf_addstr(), but notice that we leave untouched
> the find_unique_abbrev() call immediately above. There was a symmetry to
> the two that has been lost.
>
> Probably either:
>
>   strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set
> 	find_unique_abbrev(one->oid.hash, abbrev),
> 	find_unique_abbrev(two->oid.hash, abbrev));
>
> or:
>
>   strbuf_addf(msg, "%s%sindex ", line_prefix, set);
>   strbuf_add_unique_abbrev(msg, one->oid.hash, abbrev);
>   strbuf_addstr(msg, "..");
>   strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
>
> would be a more appropriate refactoring. The problem is in the original
> patch (which also lacks symmetry; either this predates the multi-buffer
> find_unique_abbrev, or the original author didn't know about it), but I
> think your refactor makes it slightly worse.

I still think the automatically generated patch is a net win, but we shouldn't stop there.

Show 6 quoted lines
> I noticed because I have another series which touches these lines, and
> it wants to symmetrically swap out find_unique_abbrev for something
> else. :) I don't think it's a big enough deal to switch now (and I've
> already rebased my series which will touch these lines), but I wanted to
> mention it as a thing to watch out for as we do more of these kinds of
> automated transformations.
OK, then I'll wait for that series to land.
Show 10 quoted lines
>> --- a/submodule.c
>> +++ b/submodule.c
>> @@ -396,7 +396,7 @@ static void show_submodule_header(FILE *f, const char *path,
>>  			find_unique_abbrev(one->hash, DEFAULT_ABBREV));
>>  	if (!fast_backward && !fast_forward)
>>  		strbuf_addch(&sb, '.');
>> -	strbuf_addstr(&sb, find_unique_abbrev(two->hash, DEFAULT_ABBREV));
>> +	strbuf_add_unique_abbrev(&sb->hash, two, DEFAULT_ABBREV);
>
> This one is a similar situation, I think.
Yes, and there are some more.  Will take a look.

I don't know how to crack printf-style formats using semantic patches. It's easy for fixed formats (silly example):

	- strbuf_addf(sb, "%s%s", a, b);
	+ strbuf_addf(sb, "%s", a);
	+ strbuf_addf(sb, "%s", b);
But how to do that for arbitrary formats?  Probably not worth it..
René

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