Merge branch 'es/format-patch-rangediff'

"git format-patch" learned a new "--range-diff" option to explain
the difference between this version and the previous attempt in
the cover letter (or after the tree-dashes as a comment).

* es/format-patch-rangediff:
  format-patch: allow --range-diff to apply to a lone-patch
  format-patch: add --creation-factor tweak for --range-diff
  format-patch: teach --range-diff to respect -v/--reroll-count
  format-patch: extend --range-diff to accept revision range
  format-patch: add --range-diff option to embed diff in cover letter
  range-diff: relieve callers of low-level configuration burden
  range-diff: publish default creation factor
  range-diff: respect diff_option.file rather than assuming 'stdout'

Documentation/git-format-patch.txt

@@ -24,6 +24,7 @@ SYNOPSIS
 		   [--to=<email>] [--cc=<email>]
 		   [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
 		   [--interdiff=<previous>]
+		   [--range-diff=<previous> [--creation-factor=<percent>]]
 		   [--progress]
 		   [<common diff options>]
 		   [ <since> | <revision range> ]
@@ -238,6 +239,24 @@ feeding the result to `git send-email`.
 	the series being formatted (for example `git format-patch
 	--cover-letter --interdiff=feature/v1 -3 feature/v2`).
 
+--range-diff=<previous>::
+	As a reviewer aid, insert a range-diff (see linkgit:git-range-diff[1])
+	into the cover letter, or as commentary of the lone patch of a
+	1-patch series, showing the differences between the previous
+	version of the patch series and the series currently being formatted.
+	`previous` can be a single revision naming the tip of the previous
+	series if it shares a common base with the series being formatted (for
+	example `git format-patch --cover-letter --range-diff=feature/v1 -3
+	feature/v2`), or a revision range if the two versions of the series are
+	disjoint (for example `git format-patch --cover-letter
+	--range-diff=feature/v1~3..feature/v1 -3 feature/v2`).
+
+--creation-factor=<percent>::
+	Used with `--range-diff`, tweak the heuristic which matches up commits
+	between the previous and current series of patches by adjusting the
+	creation/deletion cost fudge factor. See linkgit:git-range-diff[1])
+	for details.
+
 --notes[=<ref>]::
 	Append the notes (see linkgit:git-notes[1]) for the commit
 	after the three-dash line.

builtin/log.c

@@ -33,6 +33,7 @@
 #include "repository.h"
 #include "commit-reach.h"
 #include "interdiff.h"
+#include "range-diff.h"
 
 #define MAIL_DEFAULT_WRAP 72
 
@@ -1090,6 +1091,12 @@ static void make_cover_letter(struct rev_info *rev, int use_stdout,
 		fprintf_ln(rev->diffopt.file, "%s", rev->idiff_title);
 		show_interdiff(rev, 0);
 	}
+
+	if (rev->rdiff1) {
+		fprintf_ln(rev->diffopt.file, "%s", rev->rdiff_title);
+		show_range_diff(rev->rdiff1, rev->rdiff2,
+				rev->creation_factor, 1, &rev->diffopt);
+	}
 }
 
 static const char *clean_message_id(const char *msg_id)
@@ -1439,6 +1446,26 @@ static const char *diff_title(struct strbuf *sb, int reroll_count,
 	return sb->buf;
 }
 
+static void infer_range_diff_ranges(struct strbuf *r1,
+				    struct strbuf *r2,
+				    const char *prev,
+				    struct commit *origin,
+				    struct commit *head)
+{
+	const char *head_oid = oid_to_hex(&head->object.oid);
+
+	if (!strstr(prev, "..")) {
+		strbuf_addf(r1, "%s..%s", head_oid, prev);
+		strbuf_addf(r2, "%s..%s", prev, head_oid);
+	} else if (!origin) {
+		die(_("failed to infer range-diff ranges"));
+	} else {
+		strbuf_addstr(r1, prev);
+		strbuf_addf(r2, "%s..%s",
+			    oid_to_hex(&origin->object.oid), head_oid);
+	}
+}
+
 int cmd_format_patch(int argc, const char **argv, const char *prefix)
 {
 	struct commit *commit;
@@ -1468,6 +1495,11 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	struct progress *progress = NULL;
 	struct oid_array idiff_prev = OID_ARRAY_INIT;
 	struct strbuf idiff_title = STRBUF_INIT;
+	const char *rdiff_prev = NULL;
+	struct strbuf rdiff1 = STRBUF_INIT;
+	struct strbuf rdiff2 = STRBUF_INIT;
+	struct strbuf rdiff_title = STRBUF_INIT;
+	int creation_factor = -1;
 
 	const struct option builtin_format_patch_options[] = {
 		{ OPTION_CALLBACK, 'n', "numbered", &numbered, NULL,
@@ -1544,6 +1576,10 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK(0, "interdiff", &idiff_prev, N_("rev"),
 			     N_("show changes against <rev> in cover letter or single patch"),
 			     parse_opt_object_name),
+		OPT_STRING(0, "range-diff", &rdiff_prev, N_("refspec"),
+			   N_("show changes against <refspec> in cover letter or single patch")),
+		OPT_INTEGER(0, "creation-factor", &creation_factor,
+			    N_("percentage by which creation is weighted")),
 		OPT_END()
 	};
 
@@ -1776,6 +1812,25 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 					     _("Interdiff against v%d:"));
 	}
 
+	if (creation_factor < 0)
+		creation_factor = RANGE_DIFF_CREATION_FACTOR_DEFAULT;
+	else if (!rdiff_prev)
+		die(_("--creation-factor requires --range-diff"));
+
+	if (rdiff_prev) {
+		if (!cover_letter && total != 1)
+			die(_("--range-diff requires --cover-letter or single patch"));
+
+		infer_range_diff_ranges(&rdiff1, &rdiff2, rdiff_prev,
+					origin, list[0]);
+		rev.rdiff1 = rdiff1.buf;
+		rev.rdiff2 = rdiff2.buf;
+		rev.creation_factor = creation_factor;
+		rev.rdiff_title = diff_title(&rdiff_title, reroll_count,
+					     _("Range-diff:"),
+					     _("Range-diff against v%d:"));
+	}
+
 	if (!signature) {
 		; /* --no-signature inhibits all signatures */
 	} else if (signature && signature != git_version_string) {
@@ -1813,8 +1868,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		print_signature(rev.diffopt.file);
 		total++;
 		start_number--;
-		/* interdiff in cover-letter; omit from patches */
+		/* interdiff/range-diff in cover-letter; omit from patches */
 		rev.idiff_oid1 = NULL;
+		rev.rdiff1 = NULL;
 	}
 	rev.add_signoff = do_signoff;
 
@@ -1899,6 +1955,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 done:
 	oid_array_clear(&idiff_prev);
 	strbuf_release(&idiff_title);
+	strbuf_release(&rdiff1);
+	strbuf_release(&rdiff2);
+	strbuf_release(&rdiff_title);
 	return 0;
 }
 

builtin/range-diff.c

@@ -11,14 +11,9 @@ N_("git range-diff [<options>] <base> <old-tip> <new-tip>"),
 NULL
 };
 
-static struct strbuf *output_prefix_cb(struct diff_options *opt, void *data)
-{
-	return data;
-}
-
 int cmd_range_diff(int argc, const char **argv, const char *prefix)
 {
-	int creation_factor = 60;
+	int creation_factor = RANGE_DIFF_CREATION_FACTOR_DEFAULT;
 	struct diff_options diffopt = { NULL };
 	int simple_color = -1;
 	struct option options[] = {
@@ -29,17 +24,11 @@ int cmd_range_diff(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 	int i, j, res = 0;
-	struct strbuf four_spaces = STRBUF_INIT;
 	struct strbuf range1 = STRBUF_INIT, range2 = STRBUF_INIT;
 
 	git_config(git_diff_ui_config, NULL);
 
 	diff_setup(&diffopt);
-	diffopt.output_format = DIFF_FORMAT_PATCH;
-	diffopt.flags.suppress_diff_headers = 1;
-	diffopt.output_prefix = output_prefix_cb;
-	strbuf_addstr(&four_spaces, "    ");
-	diffopt.output_prefix_data = &four_spaces;
 
 	argc = parse_options(argc, argv, NULL, options,
 			     builtin_range_diff_usage, PARSE_OPT_KEEP_UNKNOWN |
@@ -63,12 +52,9 @@ int cmd_range_diff(int argc, const char **argv, const char *prefix)
 			     options + ARRAY_SIZE(options) - 1, /* OPT_END */
 			     builtin_range_diff_usage, 0);
 
-	if (simple_color < 1) {
-		if (!simple_color)
 	/* force color when --dual-color was used */
+	if (!simple_color)
 		diffopt.use_color = 1;
-		diffopt.flags.dual_color_diffed_diffs = 1;
-	}
 
 	if (argc == 2) {
 		if (!strstr(argv[0], ".."))
@@ -106,11 +92,10 @@ int cmd_range_diff(int argc, const char **argv, const char *prefix)
 	}
 
 	res = show_range_diff(range1.buf, range2.buf, creation_factor,
-			      &diffopt);
+			      simple_color < 1, &diffopt);
 
 	strbuf_release(&range1);
 	strbuf_release(&range2);
-	strbuf_release(&four_spaces);
 
 	return res;
 }

log-tree.c

@@ -16,6 +16,7 @@
 #include "line-log.h"
 #include "help.h"
 #include "interdiff.h"
+#include "range-diff.h"
 
 static struct decoration name_decoration = { "object names" };
 static int decoration_loaded;
@@ -751,6 +752,20 @@ void show_log(struct rev_info *opt)
 
 		memcpy(&diff_queued_diff, &dq, sizeof(diff_queued_diff));
 	}
+
+	if (cmit_fmt_is_mail(ctx.fmt) && opt->rdiff1) {
+		struct diff_queue_struct dq;
+
+		memcpy(&dq, &diff_queued_diff, sizeof(diff_queued_diff));
+		DIFF_QUEUE_CLEAR(&diff_queued_diff);
+
+		next_commentary_block(opt, NULL);
+		fprintf_ln(opt->diffopt.file, "%s", opt->rdiff_title);
+		show_range_diff(opt->rdiff1, opt->rdiff2,
+				opt->creation_factor, 1, &opt->diffopt);
+
+		memcpy(&diff_queued_diff, &dq, sizeof(diff_queued_diff));
+	}
 }
 
 int log_tree_diff_flush(struct rev_info *opt)

range-diff.c

@@ -343,7 +343,7 @@ static void output_pair_header(struct diff_options *diffopt,
 	}
 	strbuf_addf(buf, "%s\n", color_reset);
 
-	fwrite(buf->buf, buf->len, 1, stdout);
+	fwrite(buf->buf, buf->len, 1, diffopt->file);
 }
 
 static struct userdiff_driver no_func_name = {
@@ -429,8 +429,14 @@ static void output(struct string_list *a, struct string_list *b,
 	strbuf_release(&dashes);
 }
 
+static struct strbuf *output_prefix_cb(struct diff_options *opt, void *data)
+{
+	return data;
+}
+
 int show_range_diff(const char *range1, const char *range2,
-		    int creation_factor, struct diff_options *diffopt)
+		    int creation_factor, int dual_color,
+		    struct diff_options *diffopt)
 {
 	int res = 0;
 
@@ -443,9 +449,23 @@ int show_range_diff(const char *range1, const char *range2,
 		res = error(_("could not parse log for '%s'"), range2);
 
 	if (!res) {
+		struct diff_options opts;
+		struct strbuf indent = STRBUF_INIT;
+
+		memcpy(&opts, diffopt, sizeof(opts));
+		opts.output_format = DIFF_FORMAT_PATCH;
+		opts.flags.suppress_diff_headers = 1;
+		opts.flags.dual_color_diffed_diffs = dual_color;
+		opts.output_prefix = output_prefix_cb;
+		strbuf_addstr(&indent, "    ");
+		opts.output_prefix_data = &indent;
+		diff_setup_done(&opts);
+
 		find_exact_matches(&branch1, &branch2);
 		get_correspondences(&branch1, &branch2, creation_factor);
-		output(&branch1, &branch2, diffopt);
+		output(&branch1, &branch2, &opts);
+
+		strbuf_release(&indent);
 	}
 
 	string_list_clear(&branch1, 1);

range-diff.h

@@ -3,7 +3,10 @@
 
 #include "diff.h"
 
+#define RANGE_DIFF_CREATION_FACTOR_DEFAULT 60
+
 int show_range_diff(const char *range1, const char *range2,
-		    int creation_factor, struct diff_options *diffopt);
+		    int creation_factor, int dual_color,
+		    struct diff_options *diffopt);
 
 #endif

revision.h

@@ -224,6 +224,12 @@ struct rev_info {
 	const struct object_id *idiff_oid2;
 	const char *idiff_title;
 
+	/* range-diff */
+	const char *rdiff1;
+	const char *rdiff2;
+	int creation_factor;
+	const char *rdiff_title;
+
 	/* commit counts */
 	int count_left;
 	int count_right;

t/t3206-range-diff.sh

@@ -181,4 +181,16 @@ test_expect_success 'dual-coloring' '
 	test_cmp expect actual
 '
 
+for prev in topic master..topic
+do
+	test_expect_success "format-patch --range-diff=$prev" '
+		git format-patch --stdout --cover-letter --range-diff=$prev \
+			master..unmodified >actual &&
+		grep "= 1: .* s/5/A" actual &&
+		grep "= 2: .* s/4/A" actual &&
+		grep "= 3: .* s/11/B" actual &&
+		grep "= 4: .* s/12/B" actual
+	'
+done
+
 test_done