Merge branch 'sg/completion'

Clean-up and updates to command line completion (in contrib/).

* sg/completion: (22 commits)
  completion: restore removed line continuating backslash
  completion: cache the path to the repository
  completion: extract repository discovery from __gitdir()
  completion: don't guard git executions with __gitdir()
  completion: consolidate silencing errors from git commands
  completion: don't use __gitdir() for git commands
  completion: respect 'git -C <path>'
  rev-parse: add '--absolute-git-dir' option
  completion: fix completion after 'git -C <path>'
  completion: don't offer commands when 'git --opt' needs an argument
  completion: list short refs from a remote given as a URL
  completion: don't list 'HEAD' when trying refs completion outside of a repo
  completion: list refs from remote when remote's name matches a directory
  completion: respect 'git --git-dir=<path>' when listing remote refs
  completion: fix most spots not respecting 'git --git-dir=<path>'
  completion: ensure that the repository path given on the command line exists
  completion tests: add tests for the __git_refs() helper function
  completion tests: check __gitdir()'s output in the error cases
  completion tests: consolidate getting path of current working directory
  completion tests: make the $cur variable local to the test helper functions
  ...

Author: gitster

Documentation/git-rev-parse.txt

@@ -217,6 +217,10 @@ If `$GIT_DIR` is not defined and the current directory
 is not detected to lie in a Git repository or work tree
 print a message to stderr and exit with nonzero status.
 
+--absolute-git-dir::
+	Like `--git-dir`, but its output is always the canonicalized
+	absolute path.
+
 --git-common-dir::
 	Show `$GIT_COMMON_DIR` if defined, else `$GIT_DIR`.
 

builtin/rev-parse.c

@@ -802,17 +802,27 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				putchar('\n');
 				continue;
 			}
-			if (!strcmp(arg, "--git-dir")) {
+			if (!strcmp(arg, "--git-dir") ||
+			    !strcmp(arg, "--absolute-git-dir")) {
 				const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
 				char *cwd;
 				int len;
-				if (gitdir) {
-					puts(gitdir);
-					continue;
-				}
-				if (!prefix) {
-					puts(".git");
-					continue;
+				if (arg[2] == 'g') {	/* --git-dir */
+					if (gitdir) {
+						puts(gitdir);
+						continue;
+					}
+					if (!prefix) {
+						puts(".git");
+						continue;
+					}
+				} else {		/* --absolute-git-dir */
+					if (!gitdir && !prefix)
+						gitdir = ".git";
+					if (gitdir) {
+						puts(real_path(gitdir));
+						continue;
+					}
 				}
 				cwd = xgetcwd();
 				len = strlen(cwd);