Merge pull request #1556 from arrbee/diff-patch-fixes

Diff patch bug fixes

include/git2/diff.h

@@ -356,8 +356,10 @@ typedef enum {
 	GIT_DIFF_LINE_CONTEXT   = ' ',
 	GIT_DIFF_LINE_ADDITION  = '+',
 	GIT_DIFF_LINE_DELETION  = '-',
-	GIT_DIFF_LINE_ADD_EOFNL = '\n', /**< Removed line w/o LF & added one with */
-	GIT_DIFF_LINE_DEL_EOFNL = '\0', /**< LF was removed at end of file */
+
+	GIT_DIFF_LINE_CONTEXT_EOFNL = '=', /**< Both files have no LF at end */
+	GIT_DIFF_LINE_ADD_EOFNL = '>',     /**< Old has no LF at end, new does */
+	GIT_DIFF_LINE_DEL_EOFNL = '<',     /**< Old has LF at end, new does not */
 
 	/* The following values will only be sent to a `git_diff_data_cb` when
 	 * the content of a diff is being formatted (eg. through
@@ -488,6 +490,8 @@ typedef struct {
 
 /**
  * Deallocate a diff list.
+ *
+ * @param diff The previously created diff list; cannot be used after free.
  */
 GIT_EXTERN(void) git_diff_list_free(git_diff_list *diff);
 
@@ -497,12 +501,14 @@ GIT_EXTERN(void) git_diff_list_free(git_diff_list *diff);
  * This is equivalent to `git diff <old-tree> <new-tree>`
  *
  * The first tree will be used for the "old_file" side of the delta and the
- * second tree will be used for the "new_file" side of the delta.
+ * second tree will be used for the "new_file" side of the delta.  You can
+ * pass NULL to indicate an empty tree, although it is an error to pass
+ * NULL for both the `old_tree` and `new_tree`.
  *
  * @param diff Output pointer to a git_diff_list pointer to be allocated.
  * @param repo The repository containing the trees.
- * @param old_tree A git_tree object to diff from.
- * @param new_tree A git_tree object to diff to.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
+ * @param new_tree A git_tree object to diff to, or NULL for empty tree.
  * @param opts Structure with options to influence diff or NULL for defaults.
  */
 GIT_EXTERN(int) git_diff_tree_to_tree(
@@ -523,7 +529,7 @@ GIT_EXTERN(int) git_diff_tree_to_tree(
  *
  * @param diff Output pointer to a git_diff_list pointer to be allocated.
  * @param repo The repository containing the tree and index.
- * @param old_tree A git_tree object to diff from.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
  * @param index The index to diff with; repo index used if NULL.
  * @param opts Structure with options to influence diff or NULL for defaults.
  */
@@ -582,7 +588,7 @@ GIT_EXTERN(int) git_diff_index_to_workdir(
  *
  * @param diff A pointer to a git_diff_list pointer that will be allocated.
  * @param repo The repository containing the tree.
- * @param old_tree A git_tree object to diff from.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
  * @param opts Structure with options to influence diff or NULL for defaults.
  */
 GIT_EXTERN(int) git_diff_tree_to_workdir(
@@ -926,7 +932,14 @@ GIT_EXTERN(int) git_diff_patch_to_str(
  * to 1 and no call to the hunk_cb nor line_cb will be made (unless you pass
  * `GIT_DIFF_FORCE_TEXT` of course).
  *
- * @return 0 on success, GIT_EUSER on non-zero callback, or error code
+ * @param old_blob Blob for old side of diff, or NULL for empty blob
+ * @param new_blob Blob for new side of diff, or NULL for empty blob
+ * @param options Options for diff, or NULL for default options
+ * @param file_cb Callback for "file"; made once if there is a diff; can be NULL
+ * @param hunk_cb Callback for each hunk in diff; can be NULL
+ * @param line_cb Callback for each line in diff; can be NULL
+ * @param payload Payload passed to each callback function
+ * @return 0 on success, GIT_EUSER on non-zero callback return, or error code
  */
 GIT_EXTERN(int) git_diff_blobs(
 	const git_blob *old_blob,
@@ -949,7 +962,15 @@ GIT_EXTERN(int) git_diff_blobs(
  * entire content of the buffer added).  Passing NULL to the buffer will do
  * the reverse, with GIT_DELTA_REMOVED and blob content removed.
  *
- * @return 0 on success, GIT_EUSER on non-zero callback, or error code
+ * @param old_blob Blob for old side of diff, or NULL for empty blob
+ * @param buffer Raw data for new side of diff
+ * @param buffer_len Length of raw data for new side of diff
+ * @param options Options for diff, or NULL for default options
+ * @param file_cb Callback for "file"; made once if there is a diff; can be NULL
+ * @param hunk_cb Callback for each hunk in diff; can be NULL
+ * @param line_cb Callback for each line in diff; can be NULL
+ * @param payload Payload passed to each callback function
+ * @return 0 on success, GIT_EUSER on non-zero callback return, or error code
  */
 GIT_EXTERN(int) git_diff_blob_to_buffer(
 	const git_blob *old_blob,

src/diff.c

@@ -389,6 +389,9 @@ static int diff_list_apply_options(
 
 	/* Don't set GIT_DIFFCAPS_USE_DEV - compile time option in core git */
 
+	/* Set GIT_DIFFCAPS_TRUST_NANOSECS on a platform basis */
+	diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_NANOSECS;
+
 	/* If not given explicit `opts`, check `diff.xyz` configs */
 	if (!opts) {
 		diff->opts.context_lines = config_int(cfg, "diff.context", 3);
@@ -529,6 +532,13 @@ cleanup:
 	return result;
 }
 
+static bool diff_time_eq(
+	const git_index_time *a, const git_index_time *b, bool use_nanos)
+{
+	return a->seconds == a->seconds &&
+		(!use_nanos || a->nanoseconds == b->nanoseconds);
+}
+
 typedef struct {
 	git_repository *repo;
 	git_iterator *old_iter;
@@ -540,11 +550,51 @@ typedef struct {
 
 #define MODE_BITS_MASK 0000777
 
+static int maybe_modified_submodule(
+	git_delta_t *status,
+	git_oid *found_oid,
+	git_diff_list *diff,
+	diff_in_progress *info)
+{
+	int error = 0;
+	git_submodule *sub;
+	unsigned int sm_status = 0;
+	const git_oid *sm_oid;
+
+	*status = GIT_DELTA_UNMODIFIED;
+
+	if (!DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES) &&
+		!(error = git_submodule_lookup(
+			  &sub, diff->repo, info->nitem->path)) &&
+		git_submodule_ignore(sub) != GIT_SUBMODULE_IGNORE_ALL &&
+		!(error = git_submodule_status(&sm_status, sub)))
+	{
+		/* check IS_WD_UNMODIFIED because this case is only used
+		 * when the new side of the diff is the working directory
+		 */
+		if (!GIT_SUBMODULE_STATUS_IS_WD_UNMODIFIED(sm_status))
+			*status = GIT_DELTA_MODIFIED;
+
+		/* grab OID while we are here */
+		if (git_oid_iszero(&info->nitem->oid) &&
+			(sm_oid = git_submodule_wd_id(sub)) != NULL)
+			git_oid_cpy(found_oid, sm_oid);
+	}
+
+	/* GIT_EEXISTS means a dir with .git in it was found - ignore it */
+	if (error == GIT_EEXISTS) {
+		giterr_clear();
+		error = 0;
+	}
+
+	return error;
+}
+
 static int maybe_modified(
 	git_diff_list *diff,
 	diff_in_progress *info)
 {
-	git_oid noid, *use_noid = NULL;
+	git_oid noid;
 	git_delta_t status = GIT_DELTA_MODIFIED;
 	const git_index_entry *oitem = info->oitem;
 	const git_index_entry *nitem = info->nitem;
@@ -560,6 +610,8 @@ static int maybe_modified(
 			&matched_pathspec))
 		return 0;
 
+	memset(&noid, 0, sizeof(noid));
+
 	/* on platforms with no symlinks, preserve mode of existing symlinks */
 	if (S_ISLNK(omode) && S_ISREG(nmode) && new_is_workdir &&
 		!(diff->diffcaps & GIT_DIFFCAPS_HAS_SYMLINKS))
@@ -600,55 +652,30 @@ static int maybe_modified(
 	 * circumstances that can accelerate things or need special handling
 	 */
 	else if (git_oid_iszero(&nitem->oid) && new_is_workdir) {
-		/* TODO: add check against index file st_mtime to avoid racy-git */
+		bool use_ctime = ((diff->diffcaps & GIT_DIFFCAPS_TRUST_CTIME) != 0);
+		bool use_nanos = ((diff->diffcaps & GIT_DIFFCAPS_TRUST_NANOSECS) != 0);
 
-		/* if the stat data looks exactly alike, then assume the same */
-		if (omode == nmode &&
-			oitem->file_size == nitem->file_size &&
-			(!(diff->diffcaps & GIT_DIFFCAPS_TRUST_CTIME) ||
-			 (oitem->ctime.seconds == nitem->ctime.seconds)) &&
-			oitem->mtime.seconds == nitem->mtime.seconds &&
-			(!(diff->diffcaps & GIT_DIFFCAPS_USE_DEV) ||
-			 (oitem->dev == nitem->dev)) &&
-			oitem->ino == nitem->ino &&
-			oitem->uid == nitem->uid &&
-			oitem->gid == nitem->gid)
-			status = GIT_DELTA_UNMODIFIED;
+		status = GIT_DELTA_UNMODIFIED;
 
-		else if (S_ISGITLINK(nmode)) {
-			int err;
-			git_submodule *sub;
-
-			if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
-				status = GIT_DELTA_UNMODIFIED;
-			else if ((err = git_submodule_lookup(&sub, diff->repo, nitem->path)) < 0) {
-				if (err == GIT_EEXISTS)
-					status = GIT_DELTA_UNMODIFIED;
-				else
-					return err;
-			} else if (git_submodule_ignore(sub) == GIT_SUBMODULE_IGNORE_ALL)
-				status = GIT_DELTA_UNMODIFIED;
-			else {
-				unsigned int sm_status = 0;
-				if (git_submodule_status(&sm_status, sub) < 0)
-					return -1;
-
-				/* check IS_WD_UNMODIFIED because this case is only used
-				 * when the new side of the diff is the working directory
-				 */
-				status = GIT_SUBMODULE_STATUS_IS_WD_UNMODIFIED(sm_status)
-						 ? GIT_DELTA_UNMODIFIED : GIT_DELTA_MODIFIED;
-
-				/* grab OID while we are here */
-				if (git_oid_iszero(&nitem->oid)) {
-					const git_oid *sm_oid = git_submodule_wd_id(sub);
-					if (sm_oid != NULL) {
-						git_oid_cpy(&noid, sm_oid);
-						use_noid = &noid;
-					}
-				}
-			}
+		/* TODO: add check against index file st_mtime to avoid racy-git */
+
+		if (S_ISGITLINK(nmode)) {
+			if (maybe_modified_submodule(&status, &noid, diff, info) < 0)
+				return -1;
 		}
+
+		/* if the stat data looks different, then mark modified - this just
+		 * means that the OID will be recalculated below to confirm change
+		 */
+		else if (omode != nmode ||
+			oitem->file_size != nitem->file_size ||
+			!diff_time_eq(&oitem->mtime, &nitem->mtime, use_nanos) ||
+			(use_ctime &&
+			 !diff_time_eq(&oitem->ctime, &nitem->ctime, use_nanos)) ||
+			oitem->ino != nitem->ino ||
+			oitem->uid != nitem->uid ||
+			oitem->gid != nitem->gid)
+			status = GIT_DELTA_MODIFIED;
 	}
 
 	/* if mode is GITLINK and submodules are ignored, then skip */
@@ -660,11 +687,10 @@ static int maybe_modified(
 	 * haven't calculated the OID of the new item, then calculate it now
 	 */
 	if (status != GIT_DELTA_UNMODIFIED && git_oid_iszero(&nitem->oid)) {
-		if (!use_noid) {
+		if (git_oid_iszero(&noid)) {
 			if (git_diff__oid_for_file(diff->repo,
 					nitem->path, nitem->mode, nitem->file_size, &noid) < 0)
 				return -1;
-			use_noid = &noid;
 		}
 
 		/* if oid matches, then mark unmodified (except submodules, where
@@ -672,12 +698,13 @@ static int maybe_modified(
 		 * matches between the index and the workdir HEAD)
 		 */
 		if (omode == nmode && !S_ISGITLINK(omode) &&
-			git_oid_equal(&oitem->oid, use_noid))
+			git_oid_equal(&oitem->oid, &noid))
 			status = GIT_DELTA_UNMODIFIED;
 	}
 
 	return diff_delta__from_two(
-		diff, status, oitem, omode, nitem, nmode, use_noid, matched_pathspec);
+		diff, status, oitem, omode, nitem, nmode,
+		git_oid_iszero(&noid) ? NULL : &noid, matched_pathspec);
 }
 
 static bool entry_is_prefixed(

src/diff.h

@@ -26,6 +26,7 @@ enum {
 	GIT_DIFFCAPS_TRUST_MODE_BITS  = (1 << 2), /* use st_mode? */
 	GIT_DIFFCAPS_TRUST_CTIME      = (1 << 3), /* use st_ctime? */
 	GIT_DIFFCAPS_USE_DEV          = (1 << 4), /* use st_dev? */
+	GIT_DIFFCAPS_TRUST_NANOSECS   = (1 << 5), /* use stat time nanoseconds */
 };
 
 enum {

src/diff_output.c

@@ -726,7 +726,7 @@ static int diff_patch_cb(void *priv, mmbuffer_t *bufs, int len)
 		char origin =
 			(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_DEL_EOFNL :
 			(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_ADD_EOFNL :
-			GIT_DIFF_LINE_CONTEXT;
+			GIT_DIFF_LINE_CONTEXT_EOFNL;
 
 		if (ctxt->data_cb != NULL &&
 			ctxt->data_cb(patch->delta, &ctxt->range,
@@ -930,11 +930,13 @@ static int diff_patch_line_cb(
 
 	switch (line_origin) {
 	case GIT_DIFF_LINE_ADDITION:
+	case GIT_DIFF_LINE_DEL_EOFNL:
 		line->oldno = -1;
 		line->newno = patch->newno;
 		patch->newno += line->lines;
 		break;
 	case GIT_DIFF_LINE_DELETION:
+	case GIT_DIFF_LINE_ADD_EOFNL:
 		line->oldno = patch->oldno;
 		line->newno = -1;
 		patch->oldno += line->lines;

tests-clar/diff/diff_helpers.c

@@ -97,20 +97,15 @@ int diff_line_cb(
 	e->lines++;
 	switch (line_origin) {
 	case GIT_DIFF_LINE_CONTEXT:
+	case GIT_DIFF_LINE_CONTEXT_EOFNL: /* techically not a line */
 		e->line_ctxt++;
 		break;
 	case GIT_DIFF_LINE_ADDITION:
-		e->line_adds++;
-		break;
-	case GIT_DIFF_LINE_ADD_EOFNL:
-		/* technically not a line add, but we'll count it as such */
+	case GIT_DIFF_LINE_ADD_EOFNL: /* technically not a line add */
 		e->line_adds++;
 		break;
 	case GIT_DIFF_LINE_DELETION:
-		e->line_dels++;
-		break;
-	case GIT_DIFF_LINE_DEL_EOFNL:
-		/* technically not a line delete, but we'll count it as such */
+	case GIT_DIFF_LINE_DEL_EOFNL: /* technically not a line delete */
 		e->line_dels++;
 		break;
 	default:

tests-clar/diff/patch.c

@@ -226,6 +226,7 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 	size_t hdrlen, hunklen, textlen;
 	char origin;
 	int oldno, newno;
+	git_buf old_content = GIT_BUF_INIT, actual = GIT_BUF_INIT;
 	const char *new_content = "The Song of Seven Cities\n------------------------\n\nI WAS Lord of Cities very sumptuously builded.\nSeven roaring Cities paid me tribute from afar.\nIvory their outposts were--the guardrooms of them gilded,\nAnd garrisoned with Amazons invincible in war.\n\nThis is some new text;\nNot as good as the old text;\nBut here it is.\n\nSo they warred and trafficked only yesterday, my Cities.\nTo-day there is no mark or mound of where my Cities stood.\nFor the River rose at midnight and it washed away my Cities.\nThey are evened with Atlantis and the towns before the Flood.\n\nRain on rain-gorged channels raised the water-levels round them,\nFreshet backed on freshet swelled and swept their world from sight,\nTill the emboldened floods linked arms and, flashing forward, drowned them--\nDrowned my Seven Cities and their peoples in one night!\n\nLow among the alders lie their derelict foundations,\nThe beams wherein they trusted and the plinths whereon they built--\nMy rulers and their treasure and their unborn populations,\nDead, destroyed, aborted, and defiled with mud and silt!\n\nAnother replacement;\nBreaking up the poem;\nGenerating some hunks.\n\nTo the sound of trumpets shall their seed restore my Cities\nWealthy and well-weaponed, that once more may I behold\nAll the world go softly when it walks before my Cities,\nAnd the horses and the chariots fleeing from them as of old!\n\n  -- Rudyard Kipling\n";
 
 	g_repo = cl_git_sandbox_init("renames");
@@ -233,6 +234,9 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 	cl_git_pass(git_config_new(&cfg));
 	git_repository_set_config(g_repo, cfg);
 
+	cl_git_pass(
+		git_futils_readbuffer(&old_content, "renames/songof7cities.txt"));
+
 	cl_git_rewritefile("renames/songof7cities.txt", new_content);
 
 	cl_git_pass(git_repository_head_tree(&head, g_repo));
@@ -263,21 +267,24 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 0, 0));
 	cl_assert_equal_i(GIT_DIFF_LINE_CONTEXT, (int)origin);
-	cl_assert(strncmp("Ivory their outposts were--the guardrooms of them gilded,\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("Ivory their outposts were--the guardrooms of them gilded,\n", actual.ptr);
 	cl_assert_equal_i(6, oldno);
 	cl_assert_equal_i(6, newno);
 
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 0, 3));
 	cl_assert_equal_i(GIT_DIFF_LINE_DELETION, (int)origin);
-	cl_assert(strncmp("All the world went softly when it walked before my Cities--\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("All the world went softly when it walked before my Cities--\n", actual.ptr);
 	cl_assert_equal_i(9, oldno);
 	cl_assert_equal_i(-1, newno);
 
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 0, 12));
 	cl_assert_equal_i(GIT_DIFF_LINE_ADDITION, (int)origin);
-	cl_assert(strncmp("This is some new text;\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("This is some new text;\n", actual.ptr);
 	cl_assert_equal_i(-1, oldno);
 	cl_assert_equal_i(9, newno);
 
@@ -298,37 +305,116 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 1, 0));
 	cl_assert_equal_i(GIT_DIFF_LINE_CONTEXT, (int)origin);
-	cl_assert(strncmp("My rulers and their treasure and their unborn populations,\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("My rulers and their treasure and their unborn populations,\n", actual.ptr);
 	cl_assert_equal_i(31, oldno);
 	cl_assert_equal_i(25, newno);
 
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 1, 3));
 	cl_assert_equal_i(GIT_DIFF_LINE_DELETION, (int)origin);
-	cl_assert(strncmp("The Daughters of the Palace whom they cherished in my Cities,\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("The Daughters of the Palace whom they cherished in my Cities,\n", actual.ptr);
 	cl_assert_equal_i(34, oldno);
 	cl_assert_equal_i(-1, newno);
 
 	cl_git_pass(git_diff_patch_get_line_in_hunk(
 		&origin, &text, &textlen, &oldno, &newno, patch, 1, 12));
 	cl_assert_equal_i(GIT_DIFF_LINE_ADDITION, (int)origin);
-	cl_assert(strncmp("Another replacement;\n", text, textlen) == 0);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("Another replacement;\n", actual.ptr);
 	cl_assert_equal_i(-1, oldno);
 	cl_assert_equal_i(28, newno);
 
 	git_diff_patch_free(patch);
 	git_diff_list_free(diff);
+
+	/* Let's check line numbers when there is no newline */
+
+	git_buf_rtrim(&old_content);
+	cl_git_rewritefile("renames/songof7cities.txt", old_content.ptr);
+
+	cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, head, &opt));
+
+	cl_assert_equal_i(1, (int)git_diff_num_deltas(diff));
+
+	cl_git_pass(git_diff_get_patch(&patch, &delta, diff, 0));
+
+	cl_assert_equal_i(GIT_DELTA_MODIFIED, (int)delta->status);
+	cl_assert_equal_i(1, (int)git_diff_patch_num_hunks(patch));
+
+	/* check hunk 0 */
+
+	cl_git_pass(
+		git_diff_patch_get_hunk(&range, &hdr, &hdrlen, &hunklen, patch, 0));
+
+	cl_assert_equal_i(6, (int)hunklen);
+
+	cl_assert_equal_i(46, (int)range->old_start);
+	cl_assert_equal_i(4, (int)range->old_lines);
+	cl_assert_equal_i(46, (int)range->new_start);
+	cl_assert_equal_i(4, (int)range->new_lines);
+
+	cl_assert_equal_i(6, (int)git_diff_patch_num_lines_in_hunk(patch, 0));
+
+	cl_git_pass(git_diff_patch_get_line_in_hunk(
+		&origin, &text, &textlen, &oldno, &newno, patch, 0, 1));
+	cl_assert_equal_i(GIT_DIFF_LINE_CONTEXT, (int)origin);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("And the horses and the chariots fleeing from them as of old!\n", actual.ptr);
+	cl_assert_equal_i(47, oldno);
+	cl_assert_equal_i(47, newno);
+
+	cl_git_pass(git_diff_patch_get_line_in_hunk(
+		&origin, &text, &textlen, &oldno, &newno, patch, 0, 2));
+	cl_assert_equal_i(GIT_DIFF_LINE_CONTEXT, (int)origin);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("\n", actual.ptr);
+	cl_assert_equal_i(48, oldno);
+	cl_assert_equal_i(48, newno);
+
+	cl_git_pass(git_diff_patch_get_line_in_hunk(
+		&origin, &text, &textlen, &oldno, &newno, patch, 0, 3));
+	cl_assert_equal_i(GIT_DIFF_LINE_DELETION, (int)origin);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("  -- Rudyard Kipling\n", actual.ptr);
+	cl_assert_equal_i(49, oldno);
+	cl_assert_equal_i(-1, newno);
+
+	cl_git_pass(git_diff_patch_get_line_in_hunk(
+		&origin, &text, &textlen, &oldno, &newno, patch, 0, 4));
+	cl_assert_equal_i(GIT_DIFF_LINE_ADDITION, (int)origin);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("  -- Rudyard Kipling", actual.ptr);
+	cl_assert_equal_i(-1, oldno);
+	cl_assert_equal_i(49, newno);
+
+	cl_git_pass(git_diff_patch_get_line_in_hunk(
+		&origin, &text, &textlen, &oldno, &newno, patch, 0, 5));
+	cl_assert_equal_i(GIT_DIFF_LINE_DEL_EOFNL, (int)origin);
+	cl_git_pass(git_buf_set(&actual, text, textlen));
+	cl_assert_equal_s("\n\\ No newline at end of file\n", actual.ptr);
+	cl_assert_equal_i(-1, oldno);
+	cl_assert_equal_i(49, newno);
+
+	git_diff_patch_free(patch);
+	git_diff_list_free(diff);
+
+	git_buf_free(&actual);
+	git_buf_free(&old_content);
 	git_tree_free(head);
 	git_config_free(cfg);
 }
 
 static void check_single_patch_stats(
-	git_repository *repo, size_t hunks, size_t adds, size_t dels)
+	git_repository *repo, size_t hunks,
+	size_t adds, size_t dels, size_t ctxt,
+	const char *expected)
 {
 	git_diff_list *diff;
 	git_diff_patch *patch;
 	const git_diff_delta *delta;
-	size_t actual_adds, actual_dels;
+	size_t actual_ctxt, actual_adds, actual_dels;
 
 	cl_git_pass(git_diff_index_to_workdir(&diff, repo, NULL, NULL));
 
@@ -339,12 +425,52 @@ static void check_single_patch_stats(
 
 	cl_assert_equal_i((int)hunks, (int)git_diff_patch_num_hunks(patch));
 
-	cl_git_pass(
-		git_diff_patch_line_stats(NULL, &actual_adds, &actual_dels, patch));
+	cl_git_pass( git_diff_patch_line_stats(
+		&actual_ctxt, &actual_adds, &actual_dels, patch) );
 
+	cl_assert_equal_sz(ctxt, actual_ctxt);
 	cl_assert_equal_sz(adds, actual_adds);
 	cl_assert_equal_sz(dels, actual_dels);
 
+	if (expected != NULL) {
+		char *text;
+		cl_git_pass(git_diff_patch_to_str(&text, patch));
+		cl_assert_equal_s(expected, text);
+		git__free(text);
+	}
+
+	/* walk lines in hunk with basic sanity checks */
+	for (; hunks > 0; --hunks) {
+		size_t i, max_i;
+		int lastoldno = -1, oldno, lastnewno = -1, newno;
+		char origin;
+
+		max_i = git_diff_patch_num_lines_in_hunk(patch, hunks - 1);
+
+		for (i = 0; i < max_i; ++i) {
+			int expected = 1;
+
+			cl_git_pass(git_diff_patch_get_line_in_hunk(
+				&origin, NULL, NULL, &oldno, &newno, patch, hunks - 1, i));
+
+			if (origin == GIT_DIFF_LINE_ADD_EOFNL ||
+				origin == GIT_DIFF_LINE_DEL_EOFNL ||
+				origin == GIT_DIFF_LINE_CONTEXT_EOFNL)
+				expected = 0;
+
+			if (oldno >= 0) {
+				if (lastoldno >= 0)
+					cl_assert_equal_i(expected, oldno - lastoldno);
+				lastoldno = oldno;
+			}
+			if (newno >= 0) {
+				if (lastnewno >= 0)
+					cl_assert_equal_i(expected, newno - lastnewno);
+				lastnewno = newno;
+			}
+		}
+	}
+
 	git_diff_patch_free(patch);
 	git_diff_list_free(diff);
 }
@@ -369,14 +495,14 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	git_buf_consume(&content, end);
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 1, 0, 1);
+	check_single_patch_stats(g_repo, 1, 0, 1, 3, NULL);
 
 	/* remove trailing whitespace */
 
 	git_buf_rtrim(&content);
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 2, 1, 2);
+	check_single_patch_stats(g_repo, 2, 1, 2, 6, NULL);
 
 	/* add trailing whitespace */
 
@@ -388,7 +514,45 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	cl_git_pass(git_buf_putc(&content, '\n'));
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 1, 1, 1);
+	check_single_patch_stats(g_repo, 1, 1, 1, 3, NULL);
+
+	/* no trailing whitespace as context line */
+
+	{
+		/* walk back a couple lines, make space and insert char */
+		char *scan = content.ptr + content.size;
+		int i;
+
+		for (i = 0; i < 5; ++i) {
+			for (--scan; scan > content.ptr && *scan != '\n'; --scan)
+				/* seek to prev \n */;
+		}
+		cl_assert(scan > content.ptr);
+
+		/* overwrite trailing \n with right-shifted content */
+		memmove(scan + 1, scan, content.size - (scan - content.ptr) - 1);
+		/* insert '#' char into space we created */
+		scan[1] = '#';
+	}
+	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
+
+	check_single_patch_stats(
+		g_repo, 1, 1, 1, 6,
+		/* below is pasted output of 'git diff' with fn context removed */
+		"diff --git a/songof7cities.txt b/songof7cities.txt\n"
+		"index 378a7d9..3d0154e 100644\n"
+		"--- a/songof7cities.txt\n"
+		"+++ b/songof7cities.txt\n"
+		"@@ -42,7 +42,7 @@\n"
+		" \n"
+		" To the sound of trumpets shall their seed restore my Cities\n"
+		" Wealthy and well-weaponed, that once more may I behold\n"
+		"-All the world go softly when it walks before my Cities,\n"
+		"+#All the world go softly when it walks before my Cities,\n"
+		" And the horses and the chariots fleeing from them as of old!\n"
+		" \n"
+		"   -- Rudyard Kipling\n"
+		"\\ No newline at end of file\n");
 
 	git_buf_free(&content);
 	git_config_free(cfg);