[GSoC PATCH v3] rm: fix sign comparison warnings

[Arnav Bhate <bhatearnav@gmail.com>]

There are multiple places in loops, where a signed and an
unsigned data type are compared. Git uses a mix of signed and unsigned
types to store lengths of arrays. This sometimes leads to using a signed
index for an array whose length is stored in an unsigned variable or
vice versa.

get_ours_cache_pos is a special case where i, though derived from a
signed variable is never negative. Move this part to the caller side
and make i an unsigned argument of the function. Rename i to
pos to make it descriptive, now that it is a function argument.

Replace signed data types with unsigned data types and vice versa
wherever necessary. Where both signed and unsigned data types have been
used, define a new variable in the scope of the for loop for use as the
iterator. Remove #define DISABLE_SIGN_COMPARE_WARNINGS.

Signed-off-by: Arnav Bhate <bhatearnav@gmail.com>
---
 builtin/rm.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/builtin/rm.c b/builtin/rm.c
index 12ae086a55..a5c9fc644e 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -5,7 +5,6 @@
  */
 
 #define USE_THE_REPOSITORY_VARIABLE
-#define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "builtin.h"
 #include "advice.h"
@@ -40,14 +39,12 @@ static struct {
 	} *entry;
 } list;
 
-static int get_ours_cache_pos(const char *path, int pos)
+static int get_ours_cache_pos(const char *path, unsigned int inverted_pos)
 {
-	int i = -pos - 1;
-
-	while ((i < the_repository->index->cache_nr) && !strcmp(the_repository->index->cache[i]->name, path)) {
-		if (ce_stage(the_repository->index->cache[i]) == 2)
-			return i;
-		i++;
+	while ((inverted_pos < the_repository->index->cache_nr) && !strcmp(the_repository->index->cache[inverted_pos]->name, path)) {
+		if (ce_stage(the_repository->index->cache[inverted_pos]) == 2)
+			return inverted_pos;
+		inverted_pos++;
 	}
 	return -1;
 }
@@ -58,7 +55,7 @@ static void print_error_files(struct string_list *files_list,
 			      int *errs)
 {
 	if (files_list->nr) {
-		int i;
+		unsigned int i;
 		struct strbuf err_msg = STRBUF_INIT;
 
 		strbuf_addstr(&err_msg, main_msg);
@@ -83,7 +80,7 @@ static void submodules_absorb_gitdir_if_needed(void)
 
 		pos = index_name_pos(the_repository->index, name, strlen(name));
 		if (pos < 0) {
-			pos = get_ours_cache_pos(name, pos);
+			pos = get_ours_cache_pos(name, -pos - 1);
 			if (pos < 0)
 				continue;
 		}
@@ -131,7 +128,7 @@ static int check_local_mod(struct object_id *head, int index_only)
 			 * Skip unmerged entries except for populated submodules
 			 * that could lose history when removed.
 			 */
-			pos = get_ours_cache_pos(name, pos);
+			pos = get_ours_cache_pos(name, -pos - 1);
 			if (pos < 0)
 				continue;
 
@@ -314,7 +311,7 @@ int cmd_rm(int argc,
 	if (pathspec_needs_expanded_index(the_repository->index, &pathspec))
 		ensure_full_index(the_repository->index);
 
-	for (i = 0; i < the_repository->index->cache_nr; i++) {
+	for (unsigned int i = 0; i < the_repository->index->cache_nr; i++) {
 		const struct cache_entry *ce = the_repository->index->cache[i];
 
 		if (!include_sparse &&
-- 
2.48.1