[PATCH v2] branch -v: align even when branch names are in UTF-8

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Branch names are usually in ASCII so they are not the problem. The
problem most likely comes from "(no branch)" translation, which is in
UTF-8 and makes length calculation just wrong.

Update document to mention the fact that we may want ref names in
UTF-8. Encodings that produce invalid UTF-8 are safe as utf8_strwidth()
falls back to strlen(). The ones that incidentally produce valid UTF-8
sequences will cause misalignment.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 On Sat, Aug 25, 2012 at 12:25 AM, Junio C Hamano <gitster@pobox.com> wrote:
 > I agree with all of the above, but shouldn't you be computing the
 > "maxwidth" based on the strwidth in the first place?  The use of
 > maxwidth in strbuf_addf() here clearly wants "we know N columns is
 > sufficient to show all output items, so pad the string to N columns"
 > here.  Looking for assignment "item.len = xxx" in the same file
 > shows these are computed as byte length, so you are offsetting off
 > of an incorrectly computed value.
 >
 > Giving fewer padding bytes when showing a string that will occupy
 > fewer columns than it has bytes is independently necessary, once we
 > have the correct maxwidth that is computed in terms of the strwidth,
 > so this patch is not wrong per-se, but it is incomplete without a
 > correct maxwidth, no?

 Yes. This fixes that and also mentions about ref names in utf-8.

 Documentation/revisions.txt |  2 ++
 builtin/branch.c            | 12 +++++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index dc0070b..175d397 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -55,6 +55,8 @@ when you run `git cherry-pick`.
 +
 Note that any of the 'refs/*' cases above may come either from
 the '$GIT_DIR/refs' directory or from the '$GIT_DIR/packed-refs' file.
+While the ref name encoding is unspecified, UTF-8 is prefered as
+some output processing may assume ref names in UTF-8.
 
 '<refname>@\{<date>\}', e.g. 'master@\{yesterday\}', 'HEAD@\{5 minutes ago\}'::
   A ref followed by the suffix '@' with a date specification
diff --git a/builtin/branch.c b/builtin/branch.c
index 0e060f2..73ff7e7 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -17,6 +17,7 @@
 #include "revision.h"
 #include "string-list.h"
 #include "column.h"
+#include "utf8.h"
 
 static const char * const builtin_branch_usage[] = {
 	"git branch [options] [-r | -a] [--merged | --no-merged]",
@@ -354,7 +355,7 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	newitem->name = xstrdup(refname);
 	newitem->kind = kind;
 	newitem->commit = commit;
-	newitem->len = strlen(refname);
+	newitem->len = utf8_strwidth(refname);
 	newitem->dest = resolve_symref(orig_refname, prefix);
 	/* adjust for "remotes/" */
 	if (newitem->kind == REF_REMOTE_BRANCH &&
@@ -490,11 +491,12 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 	}
 
 	strbuf_addf(&name, "%s%s", prefix, item->name);
-	if (verbose)
+	if (verbose) {
+		int utf8_compensation = strlen(name.buf) - utf8_strwidth(name.buf);
 		strbuf_addf(&out, "%c %s%-*s%s", c, branch_get_color(color),
-			    maxwidth, name.buf,
+			    maxwidth + utf8_compensation, name.buf,
 			    branch_get_color(BRANCH_COLOR_RESET));
-	else
+	} else
 		strbuf_addf(&out, "%c %s%s%s", c, branch_get_color(color),
 			    name.buf, branch_get_color(BRANCH_COLOR_RESET));
 
@@ -533,7 +535,7 @@ static void show_detached(struct ref_list *ref_list)
 	if (head_commit && is_descendant_of(head_commit, ref_list->with_commit)) {
 		struct ref_item item;
 		item.name = xstrdup(_("(no branch)"));
-		item.len = strlen(item.name);
+		item.len = utf8_strwidth(item.name);
 		item.kind = REF_LOCAL_BRANCH;
 		item.dest = NULL;
 		item.commit = head_commit;
-- 
1.7.12.rc2.18.g61b472e