[PATCH v3 0/4] road to reentrant real_path

[Brandon Williams <bmwill@google.com>]

Changes in v3:

* Rewrite of `strip_last_component()` as the v2 verison didn't properly handle
  inputs like '/foo'.  Thanks to Johannes for pointing this out and suggesting
  a solution.
* Small style changes
* Revert the call in `get_common_dir_noenv()` to maintain proper functionality.

Brandon Williams (4):
  real_path: resolve symlinks by hand
  real_path: convert real_path_internal to strbuf_realpath
  real_path: create real_pathdup
  real_path: have callers use real_pathdup and strbuf_realpath

 abspath.c         | 222 ++++++++++++++++++++++++++++++++++++------------------
 builtin/init-db.c |   6 +-
 cache.h           |   3 +
 environment.c     |   2 +-
 setup.c           |  13 ++--
 sha1_file.c       |   2 +-
 submodule.c       |   2 +-
 transport.c       |   2 +-
 worktree.c        |   2 +-
 9 files changed, 169 insertions(+), 85 deletions(-)

--- interdiff from v2

diff --git a/abspath.c b/abspath.c
index df37356..79ee310 100644
--- a/abspath.c
+++ b/abspath.c
@@ -14,10 +14,17 @@ int is_directory(const char *path)
 /* removes the last path component from 'path' except if 'path' is root */
 static void strip_last_component(struct strbuf *path)
 {
-	if (path->len > offset_1st_component(path->buf)) {
-		char *last_slash = find_last_dir_sep(path->buf);
-		strbuf_setlen(path, last_slash - path->buf);
-	}
+	size_t offset = offset_1st_component(path->buf);
+	size_t len = path->len;
+
+	/* Find start of the last component */
+	while (offset < len && !is_dir_sep(path->buf[len - 1]))
+		len--;
+	/* Skip sequences of multiple path-separators */
+	while (offset < len && is_dir_sep(path->buf[len - 1]))
+		len--;
+
+	strbuf_setlen(path, len);
 }
 
 /* get (and remove) the next component in 'remaining' and place it in 'next' */
@@ -112,7 +119,7 @@ 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 (errno != ENOENT || remaining.len) {
 				if (die_on_error)
 					die_errno("Invalid path '%s'",
 						  resolved->buf);
@@ -203,7 +210,7 @@ char *real_pathdup(const char *path)
 	struct strbuf realpath = STRBUF_INIT;
 	char *retval = NULL;
 
-	if(strbuf_realpath(&realpath, path, 0))
+	if (strbuf_realpath(&realpath, path, 0))
 		retval = strbuf_detach(&realpath, NULL);
 
 	strbuf_release(&realpath);
diff --git a/setup.c b/setup.c
index 0d9fdd0..1b534a7 100644
--- a/setup.c
+++ b/setup.c
@@ -254,7 +254,7 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 		if (!is_absolute_path(data.buf))
 			strbuf_addf(&path, "%s/", gitdir);
 		strbuf_addbuf(&path, &data);
-		strbuf_realpath(sb, path.buf, 1);
+		strbuf_addstr(sb, real_path(path.buf));
 		ret = 1;
 	} else {
 		strbuf_addstr(sb, gitdir);

-- 
2.8.0.rc3.226.g39d4020