Merge branch 'as/check-ignore'

Add a new command "git check-ignore" for debugging .gitignore
files.

The variable names may want to get cleaned up but that can be done
in-tree.

* as/check-ignore:
  clean.c, ls-files.c: respect encapsulation of exclude_list_groups
  t0008: avoid brace expansion
  add git-check-ignore sub-command
  setup.c: document get_pathspec()
  add.c: extract new die_if_path_beyond_symlink() for reuse
  add.c: extract check_path_for_gitlink() from treat_gitlinks() for reuse
  pathspec.c: rename newly public functions for clarity
  add.c: move pathspec matchers into new pathspec.c for reuse
  add.c: remove unused argument from validate_pathspec()
  dir.c: improve docs for match_pathspec() and match_pathspec_depth()
  dir.c: provide clear_directory() for reclaiming dir_struct memory
  dir.c: keep track of where patterns came from
  dir.c: use a single struct exclude_list per source of excludes

Conflicts:
	builtin/ls-files.c
	dir.c

dir.h

@@ -16,21 +16,41 @@ struct dir_entry {
 #define EXC_FLAG_NEGATIVE 16
 
 /*
- * Each .gitignore file will be parsed into patterns which are then
- * appended to the relevant exclude_list (either EXC_DIRS or
- * EXC_FILE).  exclude_lists are also used to represent the list of
- * --exclude values passed via CLI args (EXC_CMDL).
+ * Each excludes file will be parsed into a fresh exclude_list which
+ * is appended to the relevant exclude_list_group (either EXC_DIRS or
+ * EXC_FILE).  An exclude_list within the EXC_CMDL exclude_list_group
+ * can also be used to represent the list of --exclude values passed
+ * via CLI args.
  */
 struct exclude_list {
 	int nr;
 	int alloc;
+
+	/* remember pointer to exclude file contents so we can free() */
+	char *filebuf;
+
+	/* origin of list, e.g. path to filename, or descriptive string */
+	const char *src;
+
 	struct exclude {
+		/*
+		 * This allows callers of last_exclude_matching() etc.
+		 * to determine the origin of the matching pattern.
+		 */
+		struct exclude_list *el;
+
 		const char *pattern;
 		int patternlen;
 		int nowildcardlen;
 		const char *base;
 		int baselen;
 		int flags;
+
+		/*
+		 * Counting starts from 1 for line numbers in ignore files,
+		 * and from -1 decrementing for patterns from CLI args.
+		 */
+		int srcpos;
 	} **excludes;
 };
 
@@ -42,9 +62,13 @@ struct exclude_list {
  */
 struct exclude_stack {
 	struct exclude_stack *prev; /* the struct exclude_stack for the parent directory */
-	char *filebuf; /* remember pointer to per-directory exclude file contents so we can free() */
 	int baselen;
-	int exclude_ix;
+	int exclude_ix; /* index of exclude_list within EXC_DIRS exclude_list_group */
+};
+
+struct exclude_list_group {
+	int nr, alloc;
+	struct exclude_list *el;
 };
 
 struct dir_struct {
@@ -62,16 +86,23 @@ struct dir_struct {
 
 	/* Exclude info */
 	const char *exclude_per_dir;
-	struct exclude_list exclude_list[3];
+
 	/*
-	 * We maintain three exclude pattern lists:
+	 * We maintain three groups of exclude pattern lists:
+	 *
 	 * EXC_CMDL lists patterns explicitly given on the command line.
 	 * EXC_DIRS lists patterns obtained from per-directory ignore files.
-	 * EXC_FILE lists patterns from fallback ignore files.
+	 * EXC_FILE lists patterns from fallback ignore files, e.g.
+	 *   - .git/info/exclude
+	 *   - core.excludesfile
+	 *
+	 * Each group contains multiple exclude lists, a single list
+	 * per source.
 	 */
 #define EXC_CMDL 0
 #define EXC_DIRS 1
 #define EXC_FILE 2
+	struct exclude_list_group exclude_list_group[3];
 
 	/*
 	 * Temporary variables which are used during loading of the
@@ -85,6 +116,12 @@ struct dir_struct {
 	char basebuf[PATH_MAX];
 };
 
+/*
+ * The ordering of these constants is significant, with
+ * higher-numbered match types signifying "closer" (i.e. more
+ * specific) matches which will override lower-numbered match types
+ * when populating the seen[] array.
+ */
 #define MATCHED_RECURSIVELY 1
 #define MATCHED_FNMATCH 2
 #define MATCHED_EXACTLY 3
@@ -129,13 +166,16 @@ extern struct exclude *last_exclude_matching_path(struct path_exclude_check *, c
 extern int is_path_excluded(struct path_exclude_check *, const char *, int namelen, int *dtype);
 
 
+extern struct exclude_list *add_exclude_list(struct dir_struct *dir,
+					     int group_type, const char *src);
 extern int add_excludes_from_file_to_list(const char *fname, const char *base, int baselen,
-					  char **buf_p, struct exclude_list *el, int check_index);
+					  struct exclude_list *el, int check_index);
 extern void add_excludes_from_file(struct dir_struct *, const char *fname);
 extern void parse_exclude_pattern(const char **string, int *patternlen, int *flags, int *nowildcardlen);
 extern void add_exclude(const char *string, const char *base,
-			int baselen, struct exclude_list *el);
+			int baselen, struct exclude_list *el, int srcpos);
 extern void clear_exclude_list(struct exclude_list *el);
+extern void clear_directory(struct dir_struct *dir);
 extern int file_exists(const char *);
 
 extern int is_inside_dir(const char *dir);