Merge branch 'bc/rev-parse-path-format'

"git rev-parse" can be explicitly told to give output as absolute
or relative path with the `--path-format=(absolute|relative)` option.

* bc/rev-parse-path-format:
  rev-parse: add option for absolute or relative path formatting
  abspath: add a function to resolve paths with missing components

Author: gitster

Documentation/git-rev-parse.txt

@@ -212,6 +212,18 @@ Options for Files
 	Only the names of the variables are listed, not their value,
 	even if they are set.
 
+--path-format=(absolute|relative)::
+	Controls the behavior of certain other options. If specified as absolute, the
+	paths printed by those options will be absolute and canonical. If specified as
+	relative, the paths will be relative to the current working directory if that
+	is possible.  The default is option specific.
++
+This option may be specified multiple times and affects only the arguments that
+follow it on the command line, either to the end of the command line or the next
+instance of this option.
+
+The following options are modified by `--path-format`:
+
 --git-dir::
 	Show `$GIT_DIR` if defined. Otherwise show the path to
 	the .git directory. The path shown, when relative, is
@@ -221,27 +233,9 @@ If `$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`.
 
---is-inside-git-dir::
-	When the current working directory is below the repository
-	directory print "true", otherwise "false".
-
---is-inside-work-tree::
-	When the current working directory is inside the work tree of the
-	repository print "true", otherwise "false".
-
---is-bare-repository::
-	When the repository is bare print "true", otherwise "false".
-
---is-shallow-repository::
-	When the repository is shallow print "true", otherwise "false".
-
 --resolve-git-dir <path>::
 	Check if <path> is a valid repository or a gitfile that
 	points at a valid repository, and print the location of the
@@ -255,19 +249,9 @@ print a message to stderr and exit with nonzero status.
 	$GIT_OBJECT_DIRECTORY is set to /foo/bar then "git rev-parse
 	--git-path objects/abc" returns /foo/bar/abc.
 
---show-cdup::
-	When the command is invoked from a subdirectory, show the
-	path of the top-level directory relative to the current
-	directory (typically a sequence of "../", or an empty string).
-
---show-prefix::
-	When the command is invoked from a subdirectory, show the
-	path of the current directory relative to the top-level
-	directory.
-
 --show-toplevel::
-	Show the absolute path of the top-level directory of the working
-	tree. If there is no working tree, report an error.
+	Show the (by default, absolute) path of the top-level directory
+	of the working tree. If there is no working tree, report an error.
 
 --show-superproject-working-tree::
 	Show the absolute path of the root of the superproject's
@@ -279,6 +263,36 @@ print a message to stderr and exit with nonzero status.
 	Show the path to the shared index file in split index mode, or
 	empty if not in split-index mode.
 
+The following options are unaffected by `--path-format`:
+
+--absolute-git-dir::
+	Like `--git-dir`, but its output is always the canonicalized
+	absolute path.
+
+--is-inside-git-dir::
+	When the current working directory is below the repository
+	directory print "true", otherwise "false".
+
+--is-inside-work-tree::
+	When the current working directory is inside the work tree of the
+	repository print "true", otherwise "false".
+
+--is-bare-repository::
+	When the repository is bare print "true", otherwise "false".
+
+--is-shallow-repository::
+	When the repository is shallow print "true", otherwise "false".
+
+--show-cdup::
+	When the command is invoked from a subdirectory, show the
+	path of the top-level directory relative to the current
+	directory (typically a sequence of "../", or an empty string).
+
+--show-prefix::
+	When the command is invoked from a subdirectory, show the
+	path of the current directory relative to the top-level
+	directory.
+
 --show-object-format[=(storage|input|output)]::
 	Show the object format (hash algorithm) used for the repository
 	for storage inside the `.git` directory, input, or output. For

abspath.c

@@ -67,19 +67,15 @@ static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
 #endif
 
 /*
- * Return the real path (i.e., absolute path, with symlinks resolved
- * and extra slashes removed) equivalent to the specified path.  (If
- * you want an absolute path but don't mind links, use
- * absolute_path().)  Places the resolved realpath in the provided strbuf.
- *
- * The directory part of path (i.e., everything up to the last
- * dir_sep) must denote a valid, existing directory, but the last
- * component need not exist.  If die_on_error is set, then die with an
- * informative error message if there is a problem.  Otherwise, return
- * NULL on errors (without generating any output).
+ * If set, any number of trailing components may be missing; otherwise, only one
+ * may be.
  */
-char *strbuf_realpath(struct strbuf *resolved, const char *path,
-		      int die_on_error)
+#define REALPATH_MANY_MISSING (1 << 0)
+/* Should we die if there's an error? */
+#define REALPATH_DIE_ON_ERROR (1 << 1)
+
+static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
+			       int flags)
 {
 	struct strbuf remaining = STRBUF_INIT;
 	struct strbuf next = STRBUF_INIT;
@@ -89,7 +85,7 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 	struct stat st;
 
 	if (!*path) {
-		if (die_on_error)
+		if (flags & REALPATH_DIE_ON_ERROR)
 			die("The empty string is not a valid path");
 		else
 			goto error_out;
@@ -101,7 +97,7 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 	if (!resolved->len) {
 		/* relative path; can use CWD as the initial resolved path */
 		if (strbuf_getcwd(resolved)) {
-			if (die_on_error)
+			if (flags & REALPATH_DIE_ON_ERROR)
 				die_errno("unable to get current working directory");
 			else
 				goto error_out;
@@ -129,8 +125,9 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 
 		if (lstat(resolved->buf, &st)) {
 			/* error out unless this was the last component */
-			if (errno != ENOENT || remaining.len) {
-				if (die_on_error)
+			if (errno != ENOENT ||
+			   (!(flags & REALPATH_MANY_MISSING) && remaining.len)) {
+				if (flags & REALPATH_DIE_ON_ERROR)
 					die_errno("Invalid path '%s'",
 						  resolved->buf);
 				else
@@ -143,7 +140,7 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 			if (num_symlinks++ > MAXSYMLINKS) {
 				errno = ELOOP;
 
-				if (die_on_error)
+				if (flags & REALPATH_DIE_ON_ERROR)
 					die("More than %d nested symlinks "
 					    "on path '%s'", MAXSYMLINKS, path);
 				else
@@ -153,7 +150,7 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 			len = strbuf_readlink(&symlink, resolved->buf,
 					      st.st_size);
 			if (len < 0) {
-				if (die_on_error)
+				if (flags & REALPATH_DIE_ON_ERROR)
 					die_errno("Invalid symlink '%s'",
 						  resolved->buf);
 				else
@@ -202,6 +199,37 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 	return retval;
 }
 
+/*
+ * Return the real path (i.e., absolute path, with symlinks resolved
+ * and extra slashes removed) equivalent to the specified path.  (If
+ * you want an absolute path but don't mind links, use
+ * absolute_path().)  Places the resolved realpath in the provided strbuf.
+ *
+ * The directory part of path (i.e., everything up to the last
+ * dir_sep) must denote a valid, existing directory, but the last
+ * component need not exist.  If die_on_error is set, then die with an
+ * informative error message if there is a problem.  Otherwise, return
+ * NULL on errors (without generating any output).
+ */
+char *strbuf_realpath(struct strbuf *resolved, const char *path,
+		      int die_on_error)
+{
+	return strbuf_realpath_1(resolved, path,
+				 die_on_error ? REALPATH_DIE_ON_ERROR : 0);
+}
+
+/*
+ * Just like strbuf_realpath, but allows an arbitrary number of path
+ * components to be missing.
+ */
+char *strbuf_realpath_forgiving(struct strbuf *resolved, const char *path,
+				int die_on_error)
+{
+	return strbuf_realpath_1(resolved, path,
+				 ((die_on_error ? REALPATH_DIE_ON_ERROR : 0) |
+				  REALPATH_MANY_MISSING));
+}
+
 char *real_pathdup(const char *path, int die_on_error)
 {
 	struct strbuf realpath = STRBUF_INIT;