commit - 3b95caf0b7910e22d23ee16cd50fab25471e1e20
commit + b16ee0699b6283b06cc57cca68c87d89a96630dc
blob - dd6b2aa9dd850690d77fb00149d2331f76b827e3
blob + 238ecb9d0ee975efd8eacc55de14b8cfb69792de
--- lib/diff_atomize_text.c
+++ lib/diff_atomize_text.c
@@ -64,7 +64,7 @@ diff_data_atomize_text_lines_fd(struct diff_data *d)
 		while (eol == 0 && line_end < end) {
 			r = fread(buf, sizeof(char), sizeof(buf), d->root->f);
 			if (r == 0 && ferror(d->root->f))
-				return errno;
+				return EIO;
 			i = 0;
 			while (eol == 0 && i < r) {
 				if (buf[i] != '\r' && buf[i] != '\n') {
@@ -91,7 +91,7 @@ diff_data_atomize_text_lines_fd(struct diff_data *d)
 				return errno;
 			r = fread(buf, sizeof(char), sizeof(buf), d->root->f);
 			if (r == 0 && ferror(d->root->f))
-				return errno;
+				return EIO;
 			if (r > 0 && buf[0] == '\n')
 				line_end++;
 		}
blob - 0ed8a5e2244549f0bc385a02aa8eb6f5d610deac
blob + 4b7ec8090638d2752cd946046f2333347bf244ae
--- lib/diff_debug.h
+++ lib/diff_debug.h
@@ -58,8 +58,6 @@ dump_atom(const struct diff_data *left, const struct d
 			int i;
 			r = fread(buf, 1, MIN(remain, sizeof(buf)),
 			    atom->root->f);
-			if (r == -1)
-				abort(); /* cannot return error */
 			if (r == 0)
 				break;
 			remain -= r;
blob - be72763dedcb12e2baabb6fda64e06d2fcf5f598
blob + 7c2bfddb8f77a9026ec782026f3775a07e004f5e
--- lib/diff_internal.h
+++ lib/diff_internal.h
@@ -51,11 +51,6 @@ diff_range_len(const struct diff_range *r)
 	return r->end - r->start;
 }
 
-/* List of all possible return codes of a diff invocation. */
-#define DIFF_RC_USE_DIFF_ALGO_FALLBACK	-1
-#define DIFF_RC_OK			0
-/* Any positive return values are errno values from sys/errno.h */
-
 /* Indicate whether two given diff atoms match. */
 int
 diff_atom_same(bool *same,
blob - c531ad29bc45c650dd4e3dbc4773479aafd7676b
blob + 00a42243cafc3f305b117bd3a861bb075aeee435
--- lib/diff_main.c
+++ lib/diff_main.c
@@ -43,7 +43,7 @@ read_at(FILE *f, off_t at_pos, unsigned char *buf, siz
 		return errno;
 	r = fread(buf, sizeof(char), len, f);
 	if ((r == 0 || r < len) && ferror(f))
-		return errno;
+		return EIO;
 	if (r != len)
 		return EIO;
 	return 0;
@@ -627,4 +627,20 @@ diff_result_free(struct diff_result *result)
 		return;
 	ARRAYLIST_FREE(result->chunks);
 	free(result);
+}
+
+int
+diff_result_contains_printable_chunks(struct diff_result *result)
+{
+	struct diff_chunk *c;
+	enum diff_chunk_type t;
+
+	for (int i = 0; i < result->chunks.len; i++) {
+		c = &result->chunks.head[i];
+		t = diff_chunk_type(c);
+		if (t == CHUNK_MINUS || t == CHUNK_PLUS)
+			return 1;
+	}
+
+	return 0;
 }
blob - 5e816ae10b5948c0aeacd27365a91f3147b96baf
blob + fa9dc982956eab298f65b4b9ffca114a46b50b76
--- lib/diff_main.h
+++ lib/diff_main.h
@@ -251,3 +251,4 @@ struct diff_result *diff_main(const struct diff_config
 			      struct diff_data *left,
 			      struct diff_data *right);
 void diff_result_free(struct diff_result *result);
+int diff_result_contains_printable_chunks(struct diff_result *result);
blob - 74b22eb8207ab2c5f154a22229051900a3d7b1ce
blob + b20dabf6658691770d21bfe3c1227ae815223474
--- lib/diff_output_unidiff.c
+++ lib/diff_output_unidiff.c
@@ -391,6 +391,11 @@ output_unidiff_chunk(struct diff_output_info *outinfo,
 				  cc->left.end - chunk_end_line);
 		if (rc)
 			return rc;
+
+		rc = diff_output_trailing_newline_msg(outinfo, dest,
+				&result->chunks.head[result->chunks.len - 1]);
+		if (rc != DIFF_RC_OK)
+			return rc;
 	}
 
 	return DIFF_RC_OK;