Re: [PATCH v2 6/7] wt-status.c: handle worktree renames

> Before 425a28e0a4 (diff-lib: allow ita entries treated as "not yet exist
> in index" - 2016-10-24) there are never "new files" in the index, which
> essentially disables rename detection because we only detect renames
> when a new file appears in a diff pair.
> 
> After that commit, an i-t-a entry can appear as a new file in "git
> diff-files". But the diff callback function in wt-status.c does not
> handle this case and produces incorrect status output.
> 
> PS. The reader may notice that this patch adds a new xstrdup() but not
> a free(). Yes we leak memory (the same for head_path). But wt_status
> so far has been short lived, this leak should not matter in
> practice.
> 
> Noticed-by: Alex Vandiver <alexmv@dropbox.com>
> Helped-by: Igor Djordjevic <igor.d.djordjevic@gmail.com>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  t/t2203-add-intent.sh | 28 ++++++++++++++++++++
>  wt-status.c           | 72 +++++++++++++++++++++++++++++++++++++++------------
>  wt-status.h           |  4 +--
>  3 files changed, 85 insertions(+), 19 deletions(-)
> 
> diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
> index 878e73fe98..e5bfda1853 100755
> --- a/t/t2203-add-intent.sh
> +++ b/t/t2203-add-intent.sh
> @@ -162,5 +162,33 @@ test_expect_success 'commit: ita entries ignored in empty commit check' '
>  	)
>  '
>  
> +test_expect_success 'rename detection finds the right names' '
> +	git init rename-detection &&
> +	(
> +		cd rename-detection &&
> +		echo contents > first &&
> +		git add first &&
> +		git commit -m first &&
> +		mv first third &&
> +		git add -N third &&
> +
> +		git status | grep -v "^?" >actual.1 &&
> +		test_i18ngrep "renamed: *first -> third" actual.1 &&
> +
> +		git status --porcelain | grep -v "^?" >actual.2 &&
> +		cat >expected.2 <<-\EOF &&
> +		 R first -> third
> +		EOF
> +		test_cmp expected.2 actual.2 &&
> +
> +		oid=12f00e90b6ef79117ce6e650416b8cf517099b78 &&
> +		git status --porcelain=v2 | grep -v "^?" >actual.3 &&
> +		cat >expected.3 <<-EOF &&
> +		2 .R N... 100644 100644 100644 $oid $oid R100 first	third
> +		EOF
> +		test_cmp expected.3 actual.3
> +	)
> +'
> +
>  test_done

> diff --git a/wt-status.c b/wt-status.c
> index c124d7589c..d5bdf4c2e9 100644
> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -376,6 +376,8 @@ static void wt_longstatus_print_change_data(struct wt_status *s,
>  			strbuf_addch(&extra, ')');
>  		}
>  		status = d->worktree_status;
> +		if (d->worktree_path)
> +			two_name = d->worktree_path;
>  		break;
>  	default:
>  		die("BUG: unhandled change_type %d in wt_longstatus_print_change_data",
> @@ -460,6 +462,12 @@ static void wt_status_collect_changed_cb(struct diff_queue_struct *q,
>  			/* mode_worktree is zero for a delete. */
>  			break;
>  
> +		case DIFF_STATUS_COPIED:
> +		case DIFF_STATUS_RENAMED:
> +			d->worktree_path = xstrdup(p->two->path);

> +			d->worktree_score = p->score * 100 / MAX_SCORE;
> +			/* fallthru */
> +
>  		case DIFF_STATUS_MODIFIED:
>  		case DIFF_STATUS_TYPE_CHANGED:
>  		case DIFF_STATUS_UNMERGED:
> @@ -1712,6 +1720,7 @@ static void wt_shortstatus_status(struct string_list_item *it,
>  			 struct wt_status *s)
>  {
>  	struct wt_status_change_data *d = it->util;
> +	const char *from, *to;
>  
>  	if (d->index_status)
>  		color_fprintf(s->fp, color(WT_STATUS_UPDATED, s), "%c", d->index_status);
> @@ -1722,15 +1731,30 @@ static void wt_shortstatus_status(struct string_list_item *it,
>  	else
>  		putchar(' ');
>  	putchar(' ');
> +
> +	if (d->head_path && d->worktree_path)
> +		die("BUG: to be addressed in the next patch");
> +
> +	if (d->head_path) {
> +		from = d->head_path;
> +		to = it->string;
> +	} else if (d->worktree_path) {
> +		from = it->string;
> +		to = d->worktree_path;
> +	} else {
> +		from = it->string;
> +		to = NULL;
> +	}
>  	if (s->null_termination) {
> -		fprintf(stdout, "%s%c", it->string, 0);
> -		if (d->head_path)
> -			fprintf(stdout, "%s%c", d->head_path, 0);
> +		fprintf(stdout, "%s%c", from, 0);
> +		if (to)
> +			fprintf(stdout, "%s%c", to, 0);
>  	} else {
>  		struct strbuf onebuf = STRBUF_INIT;
>  		const char *one;
> -		if (d->head_path) {
> -			one = quote_path(d->head_path, s->prefix, &onebuf);
> +
> +		if (to) {
> +			one = quote_path(from, s->prefix, &onebuf);
>  			if (*one != '"' && strchr(one, ' ') != NULL) {
>  				putchar('"');
>  				strbuf_addch(&onebuf, '"');
> @@ -1738,8 +1762,9 @@ static void wt_shortstatus_status(struct string_list_item *it,
>  			}
>  			printf("%s -> ", one);
>  			strbuf_release(&onebuf);
> -		}
> -		one = quote_path(it->string, s->prefix, &onebuf);
> +			one = quote_path(to, s->prefix, &onebuf);
> +		} else
> +			one = quote_path(from, s->prefix, &onebuf);
>  		if (*one != '"' && strchr(one, ' ') != NULL) {
>  			putchar('"');
>  			strbuf_addch(&onebuf, '"');
> @@ -2036,12 +2061,13 @@ static void wt_porcelain_v2_print_changed_entry(
>  {
>  	struct wt_status_change_data *d = it->util;
>  	struct strbuf buf_index = STRBUF_INIT;
> -	struct strbuf buf_head = STRBUF_INIT;
> +	struct strbuf buf_other = STRBUF_INIT;
>  	const char *path_index = NULL;
> -	const char *path_head = NULL;
> -	char key[3];
> +	const char *path_other = NULL;
> +	char key[3], status_other;
>  	char submodule_token[5];
>  	char sep_char, eol_char;
> +	int score;
>  
>  	wt_porcelain_v2_fix_up_changed(it, s);
>  	wt_porcelain_v2_submodule_state(d, submodule_token);
> @@ -2050,6 +2076,19 @@ static void wt_porcelain_v2_print_changed_entry(
>  	key[1] = d->worktree_status ? d->worktree_status : '.';
>  	key[2] = 0;
>  
> +	if (d->head_path && d->worktree_path)
> +		die("BUG: to be addressed in the next patch");
> +
> +	if (d->head_path) {
> +		path_other = d->head_path;
> +		status_other = d->index_status;
> +		score = d->head_score;
> +	} else if (d->worktree_path) {
> +		path_other = d->worktree_path;
> +		status_other = d->worktree_status;
> +		score = d->worktree_score;
> +	}
> +

>  	if (s->null_termination) {
>  		/*
>  		 * In -z mode, we DO NOT C-quote pathnames.  Current path is ALWAYS first.
> @@ -2058,7 +2097,6 @@ static void wt_porcelain_v2_print_changed_entry(
>  		sep_char = '\0';
>  		eol_char = '\0';
>  		path_index = it->string;
> -		path_head = d->head_path;
>  	} else {
>  		/*
>  		 * Path(s) are C-quoted if necessary. Current path is ALWAYS first.
> @@ -2069,17 +2107,17 @@ static void wt_porcelain_v2_print_changed_entry(
>  		sep_char = '\t';
>  		eol_char = '\n';
>  		path_index = quote_path(it->string, s->prefix, &buf_index);
> -		if (d->head_path)
> -			path_head = quote_path(d->head_path, s->prefix, &buf_head);
> +		if (path_other)
> +			path_other = quote_path(path_other, s->prefix, &buf_other);
>  	}
>  
> -	if (path_head)
> +	if (path_other)
>  		fprintf(s->fp, "2 %s %s %06o %06o %06o %s %s %c%d %s%c%s%c",
>  				key, submodule_token,
>  				d->mode_head, d->mode_index, d->mode_worktree,
>  				oid_to_hex(&d->oid_head), oid_to_hex(&d->oid_index),
> -				key[0], d->head_score,
> -				path_index, sep_char, path_head, eol_char);
> +				status_other, score,
> +				path_index, sep_char, path_other, eol_char);

>  	else
>  		fprintf(s->fp, "1 %s %s %06o %06o %06o %s %s %s%c",
>  				key, submodule_token,
> @@ -2088,7 +2126,7 @@ static void wt_porcelain_v2_print_changed_entry(
>  				path_index, eol_char);
>  
>  	strbuf_release(&buf_index);
> -	strbuf_release(&buf_head);
> +	strbuf_release(&buf_other);
>  }
>  
>  /*
> diff --git a/wt-status.h b/wt-status.h
> index f9330982ac..332ff545aa 100644
> --- a/wt-status.h
> +++ b/wt-status.h
> @@ -44,10 +44,10 @@ struct wt_status_change_data {
>  	int worktree_status;
>  	int index_status;
>  	int stagemask;
> -	int head_score;
> +	int head_score, worktree_score;
>  	int mode_head, mode_index, mode_worktree;
>  	struct object_id oid_head, oid_index;
> -	char *head_path;
> +	char *head_path, *worktree_path;
>  	unsigned dirty_submodule       : 2;
>  	unsigned new_submodule_commits : 1;
>  };
>