Merge branch 'jk/config-warn-on-inaccessible-paths' into maint

The attribute system may be asked for a path that itself or its
leading directories no longer exists in the working tree, and it is
fine if we cannot open .gitattribute file in such a case.  Failure
to open per-directory .gitattributes with error status other than
ENOENT and ENOTDIR should be diagnosed.

* jk/config-warn-on-inaccessible-paths:
  attr: failure to open a .gitattributes file is OK with ENOTDIR
  warn_on_inaccessible(): a helper to warn on inaccessible paths
  attr: warn on inaccessible attribute files
  gitignore: report access errors of exclude files
  config: warn on inaccessible files

attr.c

@@ -352,8 +352,11 @@ static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
 	char buf[2048];
 	int lineno = 0;
 
-	if (!fp)
+	if (!fp) {
+		if (errno != ENOENT && errno != ENOTDIR)
+			warn_on_inaccessible(path);
 		return NULL;
+	}
 	res = xcalloc(1, sizeof(*res));
 	while (fgets(buf, sizeof(buf), fp))
 		handle_attr_line(res, buf, path, ++lineno, macro_ok);

builtin/config.c

@@ -400,8 +400,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 			 */
 			die("$HOME not set");
 
-		if (access(user_config, R_OK) &&
-		    xdg_config && !access(xdg_config, R_OK))
+		if (access_or_warn(user_config, R_OK) &&
+		    xdg_config && !access_or_warn(xdg_config, R_OK))
 			given_config_file = xdg_config;
 		else
 			given_config_file = user_config;

config.c

@@ -60,7 +60,7 @@ static int handle_path_include(const char *path, struct config_include_data *inc
 		path = buf.buf;
 	}
 
-	if (!access(path, R_OK)) {
+	if (!access_or_warn(path, R_OK)) {
 		if (++inc->depth > MAX_INCLUDE_DEPTH)
 			die(include_depth_advice, MAX_INCLUDE_DEPTH, path,
 			    cf && cf->name ? cf->name : "the command line");
@@ -939,23 +939,23 @@ int git_config_early(config_fn_t fn, void *data, const char *repo_config)
 
 	home_config_paths(&user_config, &xdg_config, "config");
 
-	if (git_config_system() && !access(git_etc_gitconfig(), R_OK)) {
+	if (git_config_system() && !access_or_warn(git_etc_gitconfig(), R_OK)) {
 		ret += git_config_from_file(fn, git_etc_gitconfig(),
 					    data);
 		found += 1;
 	}
 
-	if (xdg_config && !access(xdg_config, R_OK)) {
+	if (xdg_config && !access_or_warn(xdg_config, R_OK)) {
 		ret += git_config_from_file(fn, xdg_config, data);
 		found += 1;
 	}
 
-	if (user_config && !access(user_config, R_OK)) {
+	if (user_config && !access_or_warn(user_config, R_OK)) {
 		ret += git_config_from_file(fn, user_config, data);
 		found += 1;
 	}
 
-	if (repo_config && !access(repo_config, R_OK)) {
+	if (repo_config && !access_or_warn(repo_config, R_OK)) {
 		ret += git_config_from_file(fn, repo_config, data);
 		found += 1;
 	}

dir.c

@@ -397,6 +397,8 @@ int add_excludes_from_file_to_list(const char *fname,
 
 	fd = open(fname, O_RDONLY);
 	if (fd < 0 || fstat(fd, &st) < 0) {
+		if (errno != ENOENT)
+			warn_on_inaccessible(fname);
 		if (0 <= fd)
 			close(fd);
 		if (!check_index ||
@@ -1311,9 +1313,9 @@ void setup_standard_excludes(struct dir_struct *dir)
 		home_config_paths(NULL, &xdg_path, "ignore");
 		excludes_file = xdg_path;
 	}
-	if (!access(path, R_OK))
+	if (!access_or_warn(path, R_OK))
 		add_excludes_from_file(dir, path);
-	if (excludes_file && !access(excludes_file, R_OK))
+	if (excludes_file && !access_or_warn(excludes_file, R_OK))
 		add_excludes_from_file(dir, excludes_file);
 }
 

git-compat-util.h

@@ -604,6 +604,12 @@ int rmdir_or_warn(const char *path);
  */
 int remove_or_warn(unsigned int mode, const char *path);
 
+/* Call access(2), but warn for any error besides ENOENT. */
+int access_or_warn(const char *path, int mode);
+
+/* Warn on an inaccessible file that ought to be accessible */
+void warn_on_inaccessible(const char *path);
+
 /* Get the passwd entry for the UID of the current process. */
 struct passwd *xgetpwuid_self(void);
 

wrapper.c

@@ -403,6 +403,19 @@ int remove_or_warn(unsigned int mode, const char *file)
 	return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 }
 
+void warn_on_inaccessible(const char *path)
+{
+	warning(_("unable to access '%s': %s"), path, strerror(errno));
+}
+
+int access_or_warn(const char *path, int mode)
+{
+	int ret = access(path, mode);
+	if (ret && errno != ENOENT)
+		warn_on_inaccessible(path);
+	return ret;
+}
+
 struct passwd *xgetpwuid_self(void)
 {
 	struct passwd *pw;