Merge branch 'jk/quote-env-path-list-component'

A recent update to receive-pack to make it easier to drop garbage
objects made it clear that GIT_ALTERNATE_OBJECT_DIRECTORIES cannot
have a pathname with a colon in it (no surprise!), and this in turn
made it impossible to push into a repository at such a path.  This
has been fixed by introducing a quoting mechanism used when
appending such a path to the colon-separated list.

* jk/quote-env-path-list-component:
  t5615-alternate-env: double-quotes in file names do not work on Windows
  t5547-push-quarantine: run the path separator test on Windows, too
  tmp-objdir: quote paths we add to alternates
  alternates: accept double-quoted paths

5 files changed, 102 insertions, 12 deletions

diff --git a/Documentation/git.txt b/Documentation/git.txt
index af191c51b1..98033302bb 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -871,6 +871,12 @@ Git so take care if using a foreign front-end.
 	specifies a ":" separated (on Windows ";" separated) list
 	of Git object directories which can be used to search for Git
 	objects. New objects will not be written to these directories.
++
+	Entries that begin with `"` (double-quote) will be interpreted
+	as C-style quoted paths, removing leading and trailing
+	double-quotes and respecting backslash escapes. E.g., the value
+	`"path-with-\"-and-:-in-it":vanilla-path` has two paths:
+	`path-with-"-and-:-in-it` and `vanilla-path`.
 
 `GIT_DIR`::
 	If the `GIT_DIR` environment variable is set then it
diff --git a/sha1_file.c b/sha1_file.c
index 9c86d1924a..1173071859 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -26,6 +26,7 @@
 #include "mru.h"
 #include "list.h"
 #include "mergesort.h"
+#include "quote.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -329,13 +330,40 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base,
 	return 0;
 }
 
+static const char *parse_alt_odb_entry(const char *string,
+				       int sep,
+				       struct strbuf *out)
+{
+	const char *end;
+
+	strbuf_reset(out);
+
+	if (*string == '#') {
+		/* comment; consume up to next separator */
+		end = strchrnul(string, sep);
+	} else if (*string == '"' && !unquote_c_style(out, string, &end)) {
+		/*
+		 * quoted path; unquote_c_style has copied the
+		 * data for us and set "end". Broken quoting (e.g.,
+		 * an entry that doesn't end with a quote) falls
+		 * back to the unquoted case below.
+		 */
+	} else {
+		/* normal, unquoted path */
+		end = strchrnul(string, sep);
+		strbuf_add(out, string, end - string);
+	}
+
+	if (*end)
+		end++;
+	return end;
+}
+
 static void link_alt_odb_entries(const char *alt, int len, int sep,
 				 const char *relative_base, int depth)
 {
-	struct string_list entries = STRING_LIST_INIT_NODUP;
-	char *alt_copy;
-	int i;
 	struct strbuf objdirbuf = STRBUF_INIT;
+	struct strbuf entry = STRBUF_INIT;
 
 	if (depth > 5) {
 		error("%s: ignoring alternate object stores, nesting too deep.",
@@ -348,16 +376,13 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 		die("unable to normalize object directory: %s",
 		    objdirbuf.buf);
 
-	alt_copy = xmemdupz(alt, len);
-	string_list_split_in_place(&entries, alt_copy, sep, -1);
-	for (i = 0; i < entries.nr; i++) {
-		const char *entry = entries.items[i].string;
-		if (entry[0] == '\0' || entry[0] == '#')
+	while (*alt) {
+		alt = parse_alt_odb_entry(alt, sep, &entry);
+		if (!entry.len)
 			continue;
-		link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
+		link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 	}
-	string_list_clear(&entries, 0);
-	free(alt_copy);
+	strbuf_release(&entry);
 	strbuf_release(&objdirbuf);
 }
 
diff --git a/t/t5547-push-quarantine.sh b/t/t5547-push-quarantine.sh
index 1e5d32d068..af9fcd833a 100755
--- a/t/t5547-push-quarantine.sh
+++ b/t/t5547-push-quarantine.sh
@@ -33,4 +33,29 @@ test_expect_success 'rejected objects are removed' '
 	test_cmp expect actual
 '
 
+test_expect_success 'push to repo path with path separator (colon)' '
+	# The interesting failure case here is when the
+	# receiving end cannot access its original object directory,
+	# so make it likely for us to generate a delta by having
+	# a non-trivial file with multiple versions.
+
+	test-genrandom foo 4096 >file.bin &&
+	git add file.bin &&
+	git commit -m bin &&
+
+	if test_have_prereq MINGW
+	then
+		pathsep=";"
+	else
+		pathsep=":"
+	fi &&
+	git clone --bare . "xxx${pathsep}yyy.git" &&
+
+	echo change >>file.bin &&
+	git commit -am change &&
+	# Note that we have to use the full path here, or it gets confused
+	# with the ssh host:path syntax.
+	git push "$(pwd)/xxx${pathsep}yyy.git" HEAD
+'
+
 test_done
diff --git a/t/t5615-alternate-env.sh b/t/t5615-alternate-env.sh
index eec4137ca5..26ebb0375d 100755
--- a/t/t5615-alternate-env.sh
+++ b/t/t5615-alternate-env.sh
@@ -68,4 +68,22 @@ test_expect_success 'access alternate via relative path (subdir)' '
 	EOF
 '
 
+# set variables outside test to avoid quote insanity; the \057 is '/',
+# which doesn't need quoting, but just confirms that de-quoting
+# is working.
+quoted='"one.git\057objects"'
+unquoted='two.git/objects'
+test_expect_success 'mix of quoted and unquoted alternates' '
+	check_obj "$quoted:$unquoted" <<-EOF
+	$one blob
+	$two blob
+'
+
+test_expect_success !MINGW 'broken quoting falls back to interpreting raw' '
+	mv one.git \"one.git &&
+	check_obj \"one.git/objects <<-EOF
+	$one blob
+	EOF
+'
+
 test_done
diff --git a/tmp-objdir.c b/tmp-objdir.c
index 64435f23a4..b2d9280f10 100644
--- a/tmp-objdir.c
+++ b/tmp-objdir.c
@@ -5,6 +5,7 @@
 #include "string-list.h"
 #include "strbuf.h"
 #include "argv-array.h"
+#include "quote.h"
 
 struct tmp_objdir {
 	struct strbuf path;
@@ -79,12 +80,27 @@ static void remove_tmp_objdir_on_signal(int signo)
  */
 static void env_append(struct argv_array *env, const char *key, const char *val)
 {
-	const char *old = getenv(key);
+	struct strbuf quoted = STRBUF_INIT;
+	const char *old;
 
+	/*
+	 * Avoid quoting if it's not necessary, for maximum compatibility
+	 * with older parsers which don't understand the quoting.
+	 */
+	if (*val == '"' || strchr(val, PATH_SEP)) {
+		strbuf_addch(&quoted, '"');
+		quote_c_style(val, &quoted, NULL, 1);
+		strbuf_addch(&quoted, '"');
+		val = quoted.buf;
+	}
+
+	old = getenv(key);
 	if (!old)
 		argv_array_pushf(env, "%s=%s", key, val);
 	else
 		argv_array_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
+
+	strbuf_release(&quoted);
 }
 
 static void env_replace(struct argv_array *env, const char *key, const char *val)