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

3 files changed, 102 insertions, 7 deletions

diff --git a/Documentation/git-check-ignore.txt b/Documentation/git-check-ignore.txt
new file mode 100644
index 0000000000..854e4d0c42
--- /dev/null
+++ b/Documentation/git-check-ignore.txt
@@ -0,0 +1,89 @@
+git-check-ignore(1)
+===================
+
+NAME
+----
+git-check-ignore - Debug gitignore / exclude files
+
+
+SYNOPSIS
+--------
+[verse]
+'git check-ignore' [options] pathname...
+'git check-ignore' [options] --stdin < <list-of-paths>
+
+DESCRIPTION
+-----------
+
+For each pathname given via the command-line or from a file via
+`--stdin`, show the pattern from .gitignore (or other input files to
+the exclude mechanism) that decides if the pathname is excluded or
+included.  Later patterns within a file take precedence over earlier
+ones.
+
+OPTIONS
+-------
+-q, --quiet::
+	Don't output anything, just set exit status.  This is only
+	valid with a single pathname.
+
+-v, --verbose::
+	Also output details about the matching pattern (if any)
+	for each given pathname.
+
+--stdin::
+	Read file names from stdin instead of from the command-line.
+
+-z::
+	The output format is modified to be machine-parseable (see
+	below).  If `--stdin` is also given, input paths are separated
+	with a NUL character instead of a linefeed character.
+
+OUTPUT
+------
+
+By default, any of the given pathnames which match an ignore pattern
+will be output, one per line.  If no pattern matches a given path,
+nothing will be output for that path; this means that path will not be
+ignored.
+
+If `--verbose` is specified, the output is a series of lines of the form:
+
+<source> <COLON> <linenum> <COLON> <pattern> <HT> <pathname>
+
+<pathname> is the path of a file being queried, <pattern> is the
+matching pattern, <source> is the pattern's source file, and <linenum>
+is the line number of the pattern within that source.  If the pattern
+contained a `!` prefix or `/` suffix, it will be preserved in the
+output.  <source> will be an absolute path when referring to the file
+configured by `core.excludesfile`, or relative to the repository root
+when referring to `.git/info/exclude` or a per-directory exclude file.
+
+If `-z` is specified, the pathnames in the output are delimited by the
+null character; if `--verbose` is also specified then null characters
+are also used instead of colons and hard tabs:
+
+<source> <NULL> <linenum> <NULL> <pattern> <NULL> <pathname> <NULL>
+
+
+EXIT STATUS
+-----------
+
+0::
+	One or more of the provided paths is ignored.
+
+1::
+	None of the provided paths are ignored.
+
+128::
+	A fatal error was encountered.
+
+SEE ALSO
+--------
+linkgit:gitignore[5]
+linkgit:gitconfig[5]
+linkgit:git-ls-files[5]
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
index 91a6438031..0da205fd97 100644
--- a/Documentation/gitignore.txt
+++ b/Documentation/gitignore.txt
@@ -184,8 +184,10 @@ The second .gitignore prevents git from ignoring
 
 SEE ALSO
 --------
-linkgit:git-rm[1], linkgit:git-update-index[1],
-linkgit:gitrepository-layout[5]
+linkgit:git-rm[1],
+linkgit:git-update-index[1],
+linkgit:gitrepository-layout[5],
+linkgit:git-check-ignore[1]
 
 GIT
 ---
diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt
index 944fc39fac..9d3e3527e4 100644
--- a/Documentation/technical/api-directory-listing.txt
+++ b/Documentation/technical/api-directory-listing.txt
@@ -67,11 +67,13 @@ marked. If you to exclude files, make sure you have loaded index first.
 * Prepare `struct dir_struct dir` and clear it with `memset(&dir, 0,
   sizeof(dir))`.
 
-* Call `add_exclude()` to add single exclude pattern,
-  `add_excludes_from_file()` to add patterns from a file
-  (e.g. `.git/info/exclude`), and/or set `dir.exclude_per_dir`.  A
-  short-hand function `setup_standard_excludes()` can be used to set up
-  the standard set of exclude settings.
+* To add single exclude pattern, call `add_exclude_list()` and then
+  `add_exclude()`.
+
+* To add patterns from a file (e.g. `.git/info/exclude`), call
+  `add_excludes_from_file()` , and/or set `dir.exclude_per_dir`.  A
+  short-hand function `setup_standard_excludes()` can be used to set
+  up the standard set of exclude settings.
 
 * Set options described in the Data Structure section above.
 
@@ -79,4 +81,6 @@ marked. If you to exclude files, make sure you have loaded index first.
 
 * Use `dir.entries[]`.
 
+* Call `clear_directory()` when none of the contained elements are no longer in use.
+
 (JC)