line-log: route -L output through the standard diff pipeline

`git log -L` has always bypassed the standard diff pipeline.
`dump_diff_hacky()` in line-log.c hand-rolls its own diff headers and
hunk output, which means most diff formatting options are silently
ignored.  A NEEDSWORK comment has acknowledged this since the feature
was introduced:

    /*
     * NEEDSWORK: manually building a diff here is not the Right
     * Thing(tm).  log -L should be built into the diff pipeline.
     */

Remove `dump_diff_hacky()` and its helpers and route -L output through
`builtin_diff()` / `fn_out_consume()`, the same path used by `git diff`
and `git log -p`.  The mechanism is a pair of callback wrappers that sit
between `xdi_diff_outf()` and `fn_out_consume()`, filtering xdiff's
output to only the tracked line ranges.  To ensure xdiff emits all lines
within each range as context, the context length is inflated to span the
largest range.

Wire up the `-L` implies `--patch` default in revision setup rather
than forcing it at output time, so `line_log_print()` is just
`diffcore_std()` + `diff_flush()` with no format save/restore.
Rename detection is a no-op since pairs are already resolved during
the history walk in `queue_diffs()`, but running `diffcore_std()`
means `-S`/`-G` (pickaxe), `--orderfile`, and `--diff-filter` now
work with `-L`, and `diff_resolve_rename_copy()` sets pair statuses
correctly without manual assignment.

Switch `diff_filepair_dup()` from `xmalloc` to `xcalloc` so that new
fields (including `line_ranges`) are zero-initialized by default.

As a result, diff formatting options that were previously silently
ignored (e.g. --word-diff, --no-prefix, -w, --color-moved) now work
with -L, and output gains `index` lines, `new file mode` headers, and
funcname context in `@@` headers.  This is a user-visible output change:
tools that parse -L output may need to handle the additional header
lines.

The context-length inflation means xdiff may process more output than
needed for very wide line ranges, but benchmarks on files up to 7800
lines show no measurable regression.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -608,6 +608,52 @@ struct emit_callback {
 	struct strbuf *header;
 };
 
+/*
+ * State for the line-range callback wrappers that sit between
+ * xdi_diff_outf() and fn_out_consume().  xdiff produces a normal,
+ * unfiltered diff; the wrappers intercept each hunk header and line,
+ * track post-image position, and forward only lines that fall within
+ * the requested ranges.  Contiguous in-range lines are collected into
+ * range hunks and flushed with a synthetic @@ header so that
+ * fn_out_consume() sees well-formed unified-diff fragments.
+ *
+ * Removal lines ('-') cannot be classified by post-image position, so
+ * they are buffered in pending_rm until the next '+' or ' ' line
+ * reveals whether they precede an in-range line (flush into range hunk) or
+ * an out-of-range line (discard).
+ */
+struct line_range_callback {
+	xdiff_emit_line_fn orig_line_fn;
+	void *orig_cb_data;
+	const struct range_set *ranges;	/* 0-based [start, end) */
+	unsigned int cur_range;		/* index into the range_set */
+
+	/* Post/pre-image line counters (1-based, set from hunk headers) */
+	long lno_post;
+	long lno_pre;
+
+	/*
+	 * Function name from most recent xdiff hunk header;
+	 * size matches struct func_line.buf in xdiff/xemit.c.
+	 */
+	char func[80];
+	long funclen;
+
+	/* Range hunk being accumulated for the current range */
+	struct strbuf rhunk;
+	long rhunk_old_begin, rhunk_old_count;
+	long rhunk_new_begin, rhunk_new_count;
+	int rhunk_active;
+	int rhunk_has_changes;		/* any '+' or '-' lines? */
+
+	/* Removal lines not yet known to be in-range */
+	struct strbuf pending_rm;
+	int pending_rm_count;
+	long pending_rm_pre_begin;	/* pre-image line of first pending */
+
+	int ret;			/* latched error from orig_line_fn */
+};
+
 static int count_lines(const char *data, int size)
 {
 	int count, ch, completely_empty = 1, nl_just_seen = 0;
@@ -2493,6 +2539,188 @@ static int quick_consume(void *priv, char *line UNUSED, unsigned long len UNUSED
 	return 1;
 }
 
+static void discard_pending_rm(struct line_range_callback *s)
+{
+	strbuf_reset(&s->pending_rm);
+	s->pending_rm_count = 0;
+}
+
+static void flush_rhunk(struct line_range_callback *s)
+{
+	struct strbuf hdr = STRBUF_INIT;
+	const char *p, *end;
+
+	if (!s->rhunk_active || s->ret)
+		return;
+
+	/* Drain any pending removal lines into the range hunk */
+	if (s->pending_rm_count) {
+		strbuf_addbuf(&s->rhunk, &s->pending_rm);
+		s->rhunk_old_count += s->pending_rm_count;
+		s->rhunk_has_changes = 1;
+		discard_pending_rm(s);
+	}
+
+	/*
+	 * Suppress context-only hunks: they contain no actual changes
+	 * and would just be noise.  This can happen when the inflated
+	 * ctxlen causes xdiff to emit context covering a range that
+	 * has no changes in this commit.
+	 */
+	if (!s->rhunk_has_changes) {
+		s->rhunk_active = 0;
+		strbuf_reset(&s->rhunk);
+		return;
+	}
+
+	strbuf_addf(&hdr, "@@ -%ld,%ld +%ld,%ld @@",
+		    s->rhunk_old_begin, s->rhunk_old_count,
+		    s->rhunk_new_begin, s->rhunk_new_count);
+	if (s->funclen > 0) {
+		strbuf_addch(&hdr, ' ');
+		strbuf_add(&hdr, s->func, s->funclen);
+	}
+	strbuf_addch(&hdr, '\n');
+
+	s->ret = s->orig_line_fn(s->orig_cb_data, hdr.buf, hdr.len);
+	strbuf_release(&hdr);
+
+	/*
+	 * Replay buffered lines one at a time through fn_out_consume.
+	 * The cast discards const because xdiff_emit_line_fn takes
+	 * char *, though fn_out_consume does not modify the buffer.
+	 */
+	p = s->rhunk.buf;
+	end = p + s->rhunk.len;
+	while (!s->ret && p < end) {
+		const char *eol = memchr(p, '\n', end - p);
+		unsigned long line_len = eol ? (unsigned long)(eol - p + 1)
+					     : (unsigned long)(end - p);
+		s->ret = s->orig_line_fn(s->orig_cb_data, (char *)p, line_len);
+		p += line_len;
+	}
+
+	s->rhunk_active = 0;
+	strbuf_reset(&s->rhunk);
+}
+
+static void line_range_hunk_fn(void *data,
+			       long old_begin, long old_nr UNUSED,
+			       long new_begin, long new_nr UNUSED,
+			       const char *func, long funclen)
+{
+	struct line_range_callback *s = data;
+
+	/*
+	 * When count > 0, begin is 1-based.  When count == 0, begin is
+	 * adjusted down by 1 by xdl_emit_hunk_hdr(), but no lines of
+	 * that type will arrive, so the value is unused.
+	 *
+	 * Any pending removal lines from the previous xdiff hunk are
+	 * intentionally left in pending_rm: the line callback will
+	 * flush or discard them when the next content line reveals
+	 * whether the removals precede in-range content.
+	 */
+	s->lno_post = new_begin;
+	s->lno_pre = old_begin;
+
+	if (funclen > 0) {
+		if (funclen > (long)sizeof(s->func))
+			funclen = sizeof(s->func);
+		memcpy(s->func, func, funclen);
+	}
+	s->funclen = funclen;
+}
+
+static int line_range_line_fn(void *priv, char *line, unsigned long len)
+{
+	struct line_range_callback *s = priv;
+	const struct range *cur;
+	long lno_0, cur_pre;
+
+	if (s->ret)
+		return s->ret;
+
+	if (line[0] == '-') {
+		if (!s->pending_rm_count)
+			s->pending_rm_pre_begin = s->lno_pre;
+		s->lno_pre++;
+		strbuf_add(&s->pending_rm, line, len);
+		s->pending_rm_count++;
+		return s->ret;
+	}
+
+	if (line[0] == '\\') {
+		if (s->pending_rm_count)
+			strbuf_add(&s->pending_rm, line, len);
+		else if (s->rhunk_active)
+			strbuf_add(&s->rhunk, line, len);
+		/* otherwise outside tracked range; drop silently */
+		return s->ret;
+	}
+
+	if (line[0] != '+' && line[0] != ' ')
+		BUG("unexpected diff line type '%c'", line[0]);
+
+	lno_0 = s->lno_post - 1;
+	cur_pre = s->lno_pre;	/* save before advancing for context lines */
+	s->lno_post++;
+	if (line[0] == ' ')
+		s->lno_pre++;
+
+	/* Advance past ranges we've passed */
+	while (s->cur_range < s->ranges->nr &&
+	       lno_0 >= s->ranges->ranges[s->cur_range].end) {
+		if (s->rhunk_active)
+			flush_rhunk(s);
+		discard_pending_rm(s);
+		s->cur_range++;
+	}
+
+	/* Past all ranges */
+	if (s->cur_range >= s->ranges->nr) {
+		discard_pending_rm(s);
+		return s->ret;
+	}
+
+	cur = &s->ranges->ranges[s->cur_range];
+
+	/* Before current range */
+	if (lno_0 < cur->start) {
+		discard_pending_rm(s);
+		return s->ret;
+	}
+
+	/* In range so start a new range hunk if needed */
+	if (!s->rhunk_active) {
+		s->rhunk_active = 1;
+		s->rhunk_has_changes = 0;
+		s->rhunk_new_begin = lno_0 + 1;
+		s->rhunk_old_begin = s->pending_rm_count
+			? s->pending_rm_pre_begin : cur_pre;
+		s->rhunk_old_count = 0;
+		s->rhunk_new_count = 0;
+		strbuf_reset(&s->rhunk);
+	}
+
+	/* Flush pending removals into range hunk */
+	if (s->pending_rm_count) {
+		strbuf_addbuf(&s->rhunk, &s->pending_rm);
+		s->rhunk_old_count += s->pending_rm_count;
+		s->rhunk_has_changes = 1;
+		discard_pending_rm(s);
+	}
+
+	strbuf_add(&s->rhunk, line, len);
+	s->rhunk_new_count++;
+	if (line[0] == '+')
+		s->rhunk_has_changes = 1;
+	else
+		s->rhunk_old_count++;
+
+	return s->ret;
+}
+
 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
 {
 	const char *old_name = a;
@@ -3596,7 +3824,8 @@ static void builtin_diff(const char *name_a,
 			 const char *xfrm_msg,
 			 int must_show_header,
 			 struct diff_options *o,
-			 int complete_rewrite)
+			 int complete_rewrite,
+			 const struct range_set *line_ranges)
 {
 	mmfile_t mf1, mf2;
 	const char *lbl[2];
@@ -3837,6 +4066,52 @@ static void builtin_diff(const char *name_a,
 			 */
 			xdi_diff_outf(&mf1, &mf2, NULL, quick_consume,
 				      &ecbdata, &xpp, &xecfg);
+		} else if (line_ranges) {
+			struct line_range_callback lr_state;
+			unsigned int i;
+			long max_span = 0;
+
+			memset(&lr_state, 0, sizeof(lr_state));
+			lr_state.orig_line_fn = fn_out_consume;
+			lr_state.orig_cb_data = &ecbdata;
+			lr_state.ranges = line_ranges;
+			strbuf_init(&lr_state.rhunk, 0);
+			strbuf_init(&lr_state.pending_rm, 0);
+
+			/*
+			 * Inflate ctxlen so that all changes within
+			 * any single range are merged into one xdiff
+			 * hunk and the inter-change context is emitted.
+			 * The callback clips back to range boundaries.
+			 *
+			 * The optimal ctxlen depends on where changes
+			 * fall within the range, which is only known
+			 * after xdiff runs; the max range span is the
+			 * upper bound that guarantees correctness in a
+			 * single pass.
+			 */
+			for (i = 0; i < line_ranges->nr; i++) {
+				long span = line_ranges->ranges[i].end -
+					    line_ranges->ranges[i].start;
+				if (span > max_span)
+					max_span = span;
+			}
+			if (max_span > xecfg.ctxlen)
+				xecfg.ctxlen = max_span;
+
+			if (xdi_diff_outf(&mf1, &mf2,
+					  line_range_hunk_fn,
+					  line_range_line_fn,
+					  &lr_state, &xpp, &xecfg))
+				die("unable to generate diff for %s",
+				    one->path);
+
+			flush_rhunk(&lr_state);
+			if (lr_state.ret)
+				die("unable to generate diff for %s",
+				    one->path);
+			strbuf_release(&lr_state.rhunk);
+			strbuf_release(&lr_state.pending_rm);
 		} else if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
 					 &ecbdata, &xpp, &xecfg))
 			die("unable to generate diff for %s", one->path);
@@ -4678,7 +4953,7 @@ static void run_diff_cmd(const struct external_diff *pgm,
 
 		builtin_diff(name, other ? other : name,
 			     one, two, xfrm_msg, must_show_header,
-			     o, complete_rewrite);
+			     o, complete_rewrite, p->line_ranges);
 		if (p->status == DIFF_STATUS_COPIED ||
 		    p->status == DIFF_STATUS_RENAMED)
 			o->found_changes = 1;

diffcore.h

@@ -19,6 +19,17 @@ struct userdiff_driver;
  * in anything else.
  */
 
+/* A range [start, end).  Lines are numbered starting at 0. */
+struct range {
+	long start, end;
+};
+
+/* A set of ranges.  The ranges must always be disjoint and sorted. */
+struct range_set {
+	unsigned int alloc, nr;
+	struct range *ranges;
+};
+
 /* We internally use unsigned short as the score value,
  * and rely on an int capable to hold 32-bits.  -B can take
  * -Bmerge_score/break_score format and the two scores are
@@ -106,6 +117,11 @@ int diff_filespec_is_binary(struct repository *, struct diff_filespec *);
 struct diff_filepair {
 	struct diff_filespec *one;
 	struct diff_filespec *two;
+	/*
+	 * Tracked line ranges for -L filtering; borrowed from
+	 * line_log_data and must not be freed.
+	 */
+	const struct range_set *line_ranges;
 	unsigned short int score;
 	char status; /* M C R A D U etc. (see Documentation/diff-format.adoc or DIFF_STATUS_* in diff.h) */
 	unsigned broken_pair : 1;

line-log.c

@@ -885,160 +885,6 @@ static void queue_diffs(struct line_log_data *range,
 	move_diff_queue(queue, &diff_queued_diff);
 }
 
-static char *get_nth_line(long line, unsigned long *ends, void *data)
-{
-	if (line == 0)
-		return (char *)data;
-	else
-		return (char *)data + ends[line] + 1;
-}
-
-static void print_line(const char *prefix, char first,
-		       long line, unsigned long *ends, void *data,
-		       const char *color, const char *reset, FILE *file)
-{
-	char *begin = get_nth_line(line, ends, data);
-	char *end = get_nth_line(line+1, ends, data);
-	int had_nl = 0;
-
-	if (end > begin && end[-1] == '\n') {
-		end--;
-		had_nl = 1;
-	}
-
-	fputs(prefix, file);
-	fputs(color, file);
-	putc(first, file);
-	fwrite(begin, 1, end-begin, file);
-	fputs(reset, file);
-	putc('\n', file);
-	if (!had_nl)
-		fputs("\\ No newline at end of file\n", file);
-}
-
-static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *range)
-{
-	unsigned int i, j = 0;
-	long p_lines, t_lines;
-	unsigned long *p_ends = NULL, *t_ends = NULL;
-	struct diff_filepair *pair = range->pair;
-	struct diff_ranges *diff = &range->diff;
-
-	struct diff_options *opt = &rev->diffopt;
-	const char *prefix = diff_line_prefix(opt);
-	const char *c_reset = diff_get_color(opt->use_color, DIFF_RESET);
-	const char *c_frag = diff_get_color(opt->use_color, DIFF_FRAGINFO);
-	const char *c_meta = diff_get_color(opt->use_color, DIFF_METAINFO);
-	const char *c_old = diff_get_color(opt->use_color, DIFF_FILE_OLD);
-	const char *c_new = diff_get_color(opt->use_color, DIFF_FILE_NEW);
-	const char *c_context = diff_get_color(opt->use_color, DIFF_CONTEXT);
-
-	if (!pair || !diff)
-		goto out;
-
-	if (pair->one->oid_valid)
-		fill_line_ends(rev->diffopt.repo, pair->one, &p_lines, &p_ends);
-	fill_line_ends(rev->diffopt.repo, pair->two, &t_lines, &t_ends);
-
-	fprintf(opt->file, "%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
-	fprintf(opt->file, "%s%s--- %s%s%s\n", prefix, c_meta,
-	       pair->one->oid_valid ? "a/" : "",
-	       pair->one->oid_valid ? pair->one->path : "/dev/null",
-	       c_reset);
-	fprintf(opt->file, "%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
-	for (i = 0; i < range->ranges.nr; i++) {
-		long p_start, p_end;
-		long t_start = range->ranges.ranges[i].start;
-		long t_end = range->ranges.ranges[i].end;
-		long t_cur = t_start;
-		unsigned int j_last;
-
-		/*
-		 * If a diff range touches multiple line ranges, then all
-		 * those line ranges should be shown, so take a step back if
-		 * the current line range is still in the previous diff range
-		 * (even if only partially).
-		 */
-		if (j > 0 && diff->target.ranges[j-1].end > t_start)
-			j--;
-
-		while (j < diff->target.nr && diff->target.ranges[j].end < t_start)
-			j++;
-		if (j == diff->target.nr || diff->target.ranges[j].start >= t_end)
-			continue;
-
-		/* Scan ahead to determine the last diff that falls in this range */
-		j_last = j;
-		while (j_last < diff->target.nr && diff->target.ranges[j_last].start < t_end)
-			j_last++;
-		if (j_last > j)
-			j_last--;
-
-		/*
-		 * Compute parent hunk headers: we know that the diff
-		 * has the correct line numbers (but not all hunks).
-		 * So it suffices to shift the start/end according to
-		 * the line numbers of the first/last hunk(s) that
-		 * fall in this range.
-		 */
-		if (t_start < diff->target.ranges[j].start)
-			p_start = diff->parent.ranges[j].start - (diff->target.ranges[j].start-t_start);
-		else
-			p_start = diff->parent.ranges[j].start;
-		if (t_end > diff->target.ranges[j_last].end)
-			p_end = diff->parent.ranges[j_last].end + (t_end-diff->target.ranges[j_last].end);
-		else
-			p_end = diff->parent.ranges[j_last].end;
-
-		if (!p_start && !p_end) {
-			p_start = -1;
-			p_end = -1;
-		}
-
-		/* Now output a diff hunk for this range */
-		fprintf(opt->file, "%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
-		       prefix, c_frag,
-		       p_start+1, p_end-p_start, t_start+1, t_end-t_start,
-		       c_reset);
-		while (j < diff->target.nr && diff->target.ranges[j].start < t_end) {
-			int k;
-			for (; t_cur < diff->target.ranges[j].start; t_cur++)
-				print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
-					   c_context, c_reset, opt->file);
-			for (k = diff->parent.ranges[j].start; k < diff->parent.ranges[j].end; k++)
-				print_line(prefix, '-', k, p_ends, pair->one->data,
-					   c_old, c_reset, opt->file);
-			for (; t_cur < diff->target.ranges[j].end && t_cur < t_end; t_cur++)
-				print_line(prefix, '+', t_cur, t_ends, pair->two->data,
-					   c_new, c_reset, opt->file);
-			j++;
-		}
-		for (; t_cur < t_end; t_cur++)
-			print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
-				   c_context, c_reset, opt->file);
-	}
-
-out:
-	free(p_ends);
-	free(t_ends);
-}
-
-/*
- * NEEDSWORK: manually building a diff here is not the Right
- * Thing(tm).  log -L should be built into the diff pipeline.
- */
-static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range)
-{
-	const char *prefix = diff_line_prefix(&rev->diffopt);
-
-	fprintf(rev->diffopt.file, "%s\n", prefix);
-
-	while (range) {
-		dump_diff_hacky_one(rev, range);
-		range = range->next;
-	}
-}
-
 /*
  * Unlike most other functions, this destructively operates on
  * 'range'.
@@ -1102,7 +948,7 @@ static int process_diff_filepair(struct rev_info *rev,
 
 static struct diff_filepair *diff_filepair_dup(struct diff_filepair *pair)
 {
-	struct diff_filepair *new_filepair = xmalloc(sizeof(struct diff_filepair));
+	struct diff_filepair *new_filepair = xcalloc(1, sizeof(struct diff_filepair));
 	new_filepair->one = pair->one;
 	new_filepair->two = pair->two;
 	new_filepair->one->count++;
@@ -1160,11 +1006,25 @@ static int process_all_files(struct line_log_data **range_out,
 
 int line_log_print(struct rev_info *rev, struct commit *commit)
 {
-
 	show_log(rev);
 	if (!(rev->diffopt.output_format & DIFF_FORMAT_NO_OUTPUT)) {
 		struct line_log_data *range = lookup_line_range(rev, commit);
-		dump_diff_hacky(rev, range);
+		struct line_log_data *r;
+		const char *prefix = diff_line_prefix(&rev->diffopt);
+
+		fprintf(rev->diffopt.file, "%s\n", prefix);
+
+		for (r = range; r; r = r->next) {
+			if (r->pair) {
+				struct diff_filepair *p =
+					diff_filepair_dup(r->pair);
+				p->line_ranges = &r->ranges;
+				diff_q(&diff_queued_diff, p);
+			}
+		}
+
+		diffcore_std(&rev->diffopt);
+		diff_flush(&rev->diffopt);
 	}
 	return 1;
 }

line-log.h

@@ -1,22 +1,12 @@
 #ifndef LINE_LOG_H
 #define LINE_LOG_H
 
+#include "diffcore.h" /* struct range, struct range_set */
+
 struct rev_info;
 struct commit;
 struct string_list;
 
-/* A range [start,end].  Lines are numbered starting at 0, and the
- * ranges include start but exclude end. */
-struct range {
-	long start, end;
-};
-
-/* A set of ranges.  The ranges must always be disjoint and sorted. */
-struct range_set {
-	unsigned int alloc, nr;
-	struct range *ranges;
-};
-
 /* A diff, encoded as the set of pre- and post-image ranges where the
  * files differ. A pair of ranges corresponds to a hunk. */
 struct diff_ranges {

revision.c

@@ -3111,6 +3111,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		if (want_ancestry(revs))
 			revs->limited = 1;
 		revs->topo_order = 1;
+		if (!revs->diffopt.output_format)
+			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 	}
 
 	if (revs->topo_order && !generation_numbers_enabled(the_repository))

t/t4211-line-log.sh

@@ -129,7 +129,7 @@ test_expect_success '-L with --output' '
 	git checkout parallel-change &&
 	git log --output=log -L :main:b.c >output &&
 	test_must_be_empty output &&
-	test_line_count = 70 log
+	test_line_count = 75 log
 '
 
 test_expect_success 'range_set_union' '
@@ -340,13 +340,19 @@ test_expect_success 'zero-width regex .* matches any function name' '
 '
 
 test_expect_success 'show line-log with graph' '
+	git checkout parent-oids &&
+	head_blob_old=$(git rev-parse --short HEAD^:file.c) &&
+	head_blob_new=$(git rev-parse --short HEAD:file.c) &&
+	root_blob=$(git rev-parse --short HEAD~4:file.c) &&
+	null_blob=$(test_oid zero | cut -c1-7) &&
 	qz_to_tab_space >expect <<-EOF &&
 	* $head_oid Modify func2() in file.c
 	|Z
 	| diff --git a/file.c b/file.c
+	| index $head_blob_old..$head_blob_new 100644
 	| --- a/file.c
 	| +++ b/file.c
-	| @@ -6,4 +6,4 @@
+	| @@ -6,4 +6,4 @@ int func1()
 	|  int func2()
 	|  {
 	| -    return F2;
@@ -355,6 +361,8 @@ test_expect_success 'show line-log with graph' '
 	* $root_oid Add func1() and func2() in file.c
 	ZZ
 	  diff --git a/file.c b/file.c
+	  new file mode 100644
+	  index $null_blob..$root_blob
 	  --- /dev/null
 	  +++ b/file.c
 	  @@ -0,0 +6,4 @@

t/t4211/sha1/expect.beginning-of-file

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:47:40 2013 +0100
     change at very beginning
 
 diff --git a/a.c b/a.c
+index bdb2bb1..5e709a1 100644
 --- a/a.c
 +++ b/a.c
 @@ -1,3 +1,4 @@
@@ -20,6 +21,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -1,3 +1,3 @@
@@ -35,6 +37,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +1,3 @@

t/t4211/sha1/expect.end-of-file

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -20,3 +20,5 @@
+@@ -20,3 +20,5 @@ long f(long x)
  	printf("%ld\n", f(15));
  	return 0;
 -}
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -20,3 +20,3 @@
+@@ -20,3 +20,3 @@ int main ()
  	printf("%ld\n", f(15));
  	return 0;
 -}
@@ -39,9 +41,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
-@@ -19,3 +19,3 @@
+@@ -19,3 +19,3 @@ int f(int x)
 -	printf("%d\n", f(15));
 +	printf("%ld\n", f(15));
  	return 0;
@@ -54,6 +57,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +18,3 @@

t/t4211/sha1/expect.move-support-f

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:49:50 2013 +0100
     another simple change
 
 diff --git a/b.c b/b.c
+index 5de3ea4..bf79c2f 100644
 --- a/b.c
 +++ b/b.c
 @@ -4,9 +4,9 @@
@@ -26,6 +27,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -47,6 +49,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -67,6 +70,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha1/expect.multiple

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -43,6 +45,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -71,6 +74,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -91,6 +95,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha1/expect.multiple-overlapping

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,21 @@
@@ -39,6 +40,7 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,19 @@
@@ -71,6 +73,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index e51de13..bdb2bb1 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -102,6 +105,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -134,6 +138,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,18 +3,19 @@
@@ -164,6 +169,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,18 @@

t/t4211/sha1/expect.multiple-superset

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,21 @@
@@ -39,6 +40,7 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,19 @@
@@ -71,6 +73,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index e51de13..bdb2bb1 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -102,6 +105,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -134,6 +138,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,18 +3,19 @@
@@ -164,6 +169,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,18 @@

t/t4211/sha1/expect.no-assertion-error

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:50:24 2013 +0100
     move within the file
 
 diff --git a/b.c b/b.c
+index bf79c2f..27c829c 100644
 --- a/b.c
 +++ b/b.c
 @@ -25,0 +18,9 @@
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -45,9 +47,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -63,9 +66,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -80,6 +84,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha1/expect.parallel-change-f-to-main

@@ -13,6 +13,7 @@ Date:   Thu Feb 28 10:49:50 2013 +0100
     another simple change
 
 diff --git a/b.c b/b.c
+index 5de3ea4..bf79c2f 100644
 --- a/b.c
 +++ b/b.c
 @@ -4,14 +4,14 @@
@@ -39,6 +40,7 @@ Date:   Fri Apr 12 16:15:57 2013 +0200
     change on another line of history while rename happens
 
 diff --git a/a.c b/a.c
+index 5de3ea4..01b5b65 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,14 +4,14 @@
@@ -65,6 +67,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index e51de13..bdb2bb1 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -91,6 +94,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -117,6 +121,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,13 +3,14 @@
@@ -142,6 +147,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,13 @@

t/t4211/sha1/expect.simple-f

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -26,6 +27,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -46,6 +48,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha1/expect.simple-f-to-main

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index e51de13..bdb2bb1 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -31,6 +32,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -57,6 +59,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,13 +3,14 @@
@@ -82,6 +85,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,13 @@

t/t4211/sha1/expect.simple-main

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -41,9 +43,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -58,6 +61,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha1/expect.simple-main-to-end

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -43,9 +45,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -60,6 +63,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha1/expect.two-ranges

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -41,6 +43,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 3233403..e51de13 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -69,6 +72,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 444e415..3233403 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -89,6 +93,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha1/expect.vanishes-early

@@ -5,11 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index 0b9cae5..5de3ea4 100644
 --- a/a.c
 +++ b/a.c
-@@ -22,1 +24,1 @@
--}
-\ No newline at end of file
+@@ -23,0 +24,1 @@ int main ()
 +/* incomplete lines are bad! */
 
 commit 100b61a6f2f720f812620a9d10afb3a960ccb73c
@@ -19,9 +18,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index 5e709a1..0b9cae5 100644
 --- a/a.c
 +++ b/a.c
-@@ -22,1 +22,1 @@
+@@ -22,1 +22,1 @@ int main ()
 -}
 +}
 \ No newline at end of file
@@ -33,6 +33,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..444e415
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +20,1 @@

t/t4211/sha256/expect.beginning-of-file

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:47:40 2013 +0100
     change at very beginning
 
 diff --git a/a.c b/a.c
+index 3a78aaf..d325124 100644
 --- a/a.c
 +++ b/a.c
 @@ -1,3 +1,4 @@
@@ -20,6 +21,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -1,3 +1,3 @@
@@ -35,6 +37,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +1,3 @@

t/t4211/sha256/expect.end-of-file

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -20,3 +20,5 @@
+@@ -20,3 +20,5 @@ long f(long x)
  	printf("%ld\n", f(15));
  	return 0;
 -}
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -20,3 +20,3 @@
+@@ -20,3 +20,3 @@ int main ()
  	printf("%ld\n", f(15));
  	return 0;
 -}
@@ -39,9 +41,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
-@@ -19,3 +19,3 @@
+@@ -19,3 +19,3 @@ int f(int x)
 -	printf("%d\n", f(15));
 +	printf("%ld\n", f(15));
  	return 0;
@@ -54,6 +57,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +18,3 @@

t/t4211/sha256/expect.move-support-f

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:49:50 2013 +0100
     another simple change
 
 diff --git a/b.c b/b.c
+index 62c1fc2..69cb69c 100644
 --- a/b.c
 +++ b/b.c
 @@ -4,9 +4,9 @@
@@ -26,6 +27,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -47,6 +49,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -67,6 +70,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha256/expect.multiple

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -43,6 +45,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -71,6 +74,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -91,6 +95,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha256/expect.multiple-overlapping

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,21 @@
@@ -39,6 +40,7 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,19 @@
@@ -71,6 +73,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index 75c0119..3a78aaf 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -102,6 +105,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -134,6 +138,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,18 +3,19 @@
@@ -164,6 +169,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,18 @@

t/t4211/sha256/expect.multiple-superset

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,21 @@
@@ -39,6 +40,7 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,19 +4,19 @@
@@ -71,6 +73,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index 75c0119..3a78aaf 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -102,6 +105,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,19 +3,19 @@
@@ -134,6 +138,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,18 +3,19 @@
@@ -164,6 +169,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,18 @@

t/t4211/sha256/expect.no-assertion-error

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:50:24 2013 +0100
     move within the file
 
 diff --git a/b.c b/b.c
+index 69cb69c..a0d566e 100644
 --- a/b.c
 +++ b/b.c
 @@ -25,0 +18,9 @@
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -45,9 +47,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -63,9 +66,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -80,6 +84,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha256/expect.parallel-change-f-to-main

@@ -13,6 +13,7 @@ Date:   Thu Feb 28 10:49:50 2013 +0100
     another simple change
 
 diff --git a/b.c b/b.c
+index 62c1fc2..69cb69c 100644
 --- a/b.c
 +++ b/b.c
 @@ -4,14 +4,14 @@
@@ -39,6 +40,7 @@ Date:   Fri Apr 12 16:15:57 2013 +0200
     change on another line of history while rename happens
 
 diff --git a/a.c b/a.c
+index 62c1fc2..e1e8475 100644
 --- a/a.c
 +++ b/a.c
 @@ -4,14 +4,14 @@
@@ -65,6 +67,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index 75c0119..3a78aaf 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -91,6 +94,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -117,6 +121,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,13 +3,14 @@
@@ -142,6 +147,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,13 @@

t/t4211/sha256/expect.simple-f

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -26,6 +27,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -46,6 +48,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha256/expect.simple-f-to-main

@@ -5,6 +5,7 @@ Date:   Thu Feb 28 10:45:41 2013 +0100
     touch comment
 
 diff --git a/a.c b/a.c
+index 75c0119..3a78aaf 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -31,6 +32,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,14 +3,14 @@
@@ -57,6 +59,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,13 +3,14 @@
@@ -82,6 +85,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,13 @@

t/t4211/sha256/expect.simple-main

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -41,9 +43,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -58,6 +61,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha256/expect.simple-main-to-end

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,7 @@
+@@ -18,5 +18,7 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -25,9 +26,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -43,9 +45,10 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
-@@ -17,5 +17,5 @@
+@@ -17,5 +17,5 @@ int f(int x)
  int main ()
  {
 -	printf("%d\n", f(15));
@@ -60,6 +63,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +16,5 @@

t/t4211/sha256/expect.two-ranges

@@ -5,9 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -23,9 +24,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -18,5 +18,5 @@
+@@ -18,5 +18,5 @@ long f(long x)
  int main ()
  {
  	printf("%ld\n", f(15));
@@ -41,6 +43,7 @@ Date:   Thu Feb 28 10:45:16 2013 +0100
     touch both functions
 
 diff --git a/a.c b/a.c
+index 7a296b9..75c0119 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,9 +3,9 @@
@@ -69,6 +72,7 @@ Date:   Thu Feb 28 10:44:55 2013 +0100
     change f()
 
 diff --git a/a.c b/a.c
+index 9f550c3..7a296b9 100644
 --- a/a.c
 +++ b/a.c
 @@ -3,8 +3,9 @@
@@ -89,6 +93,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +3,8 @@

t/t4211/sha256/expect.vanishes-early

@@ -5,11 +5,10 @@ Date:   Thu Feb 28 10:48:43 2013 +0100
     change back to complete line
 
 diff --git a/a.c b/a.c
+index e4fa1d8..62c1fc2 100644
 --- a/a.c
 +++ b/a.c
-@@ -22,1 +24,1 @@
--}
-\ No newline at end of file
+@@ -23,0 +24,1 @@ int main ()
 +/* incomplete lines are bad! */
 
 commit 29f32ac3141c48b22803e5c4127b719917b67d0f8ca8c5248bebfa2a19f7da10
@@ -19,9 +18,10 @@ Date:   Thu Feb 28 10:48:10 2013 +0100
     change to an incomplete line at end
 
 diff --git a/a.c b/a.c
+index d325124..e4fa1d8 100644
 --- a/a.c
 +++ b/a.c
-@@ -22,1 +22,1 @@
+@@ -22,1 +22,1 @@ int main ()
 -}
 +}
 \ No newline at end of file
@@ -33,6 +33,8 @@ Date:   Thu Feb 28 10:44:48 2013 +0100
     initial
 
 diff --git a/a.c b/a.c
+new file mode 100644
+index 0000000..9f550c3
 --- /dev/null
 +++ b/a.c
 @@ -0,0 +20,1 @@