[PATCH 1/1][RFC][GSoC] submodule: using 'is_writing_gitmodules_ok()' for a stricter check

[Shourya Shukla <shouryashukla.oo@gmail.com>]

The if conditions of the functions 'update_path_in_gitmodules()'
and 'remove_path_from_gitmodules()' are not catering to every
condition encountered by the function. On detailed observation,
one can notice that .gitmodules cannot be changed (i.e. removal
of a path or updation of a path) until these conditions are satisfied:

    1. The file exists
    2. The file, if it does not exist, should be absent from
       the index and other branches as well.
    3. There should not be any unmerged changes in the file.
    4. The submodules do not exist or if the submodule name
       does not match.

Only the conditions 1, 3 and 4 were being satisfied earlier. Now
on changing the if statement in one of the places, the condition
2 is satisfied as well.

Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
---
 submodule.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/submodule.c b/submodule.c
index 3a184b66ab..f7836a6851 100644
--- a/submodule.c
+++ b/submodule.c
@@ -107,7 +107,13 @@ int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 	const struct submodule *submodule;
 	int ret;
 
-	if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
+	/* If .gitmodules file is not safe to write(update a path) i.e.
+	 * if it does not exist or if it is not present in the working tree
+	 * but lies in the index or in the current branch.
+	 * The function 'is_writing_gitmodules_ok()' checks for the same.
+	 * and exits with failure if above conditions are not satisfied
+	*/
+	if (is_writing_gitmodules_ok())
 		return -1;
 
 	if (is_gitmodules_unmerged(the_repository->index))
@@ -136,7 +142,13 @@ int remove_path_from_gitmodules(const char *path)
 	struct strbuf sect = STRBUF_INIT;
 	const struct submodule *submodule;
 
-	if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
+	/* If .gitmodules file is not safe to write(remove a path) i.e.
+	 * if it does not exist or if it is not present in the working tree
+	 * but lies in the index or in the current branch.
+	 * The function 'is_writing_gitmodules_ok()' checks for the same.
+	 * and exits with failure if above conditions are not satisfied
+	*/
+	if (is_writing_gitmodules_ok())
 		return -1;
 
 	if (is_gitmodules_unmerged(the_repository->index))
-- 
2.20.1