Merge pull request #536: Allow --no-src during clones and git worktree after clones

These are two highly-requested items from an internal team considering a
move to Scalar using Azure Repos.

1. Remove the requirement that we create a `src` directory at clone time.

2. Allow `git worktree` even when using the GVFS protocol.

These are not difficult to implement. The `--no-src` option could even
be submitted upstream (though the commit will need to drop one bit about
an interaction with the local cache path).

Documentation/scalar.txt

@@ -9,7 +9,7 @@ SYNOPSIS
 --------
 [verse]
 scalar clone [--single-branch] [--branch <main-branch>] [--full-clone]
-	[--local-cache-path <path>] [--cache-server-url <url>]
+	[--local-cache-path <path>] [--cache-server-url <url>] [--[no-]src]
 	<url> [<enlistment>]
 scalar list
 scalar register [<enlistment>]
@@ -83,6 +83,9 @@ remote-tracking branch for the branch this option was used for the initial
 cloning. If the HEAD at the remote did not point at any branch when
 `--single-branch` clone was made, no remote-tracking branch is created.
 
+--no-src::
+	Skip adding a `src` directory within the target enlistment.
+
 --[no-]full-clone::
 	A sparse-checkout is initialized by default. This behavior can be
 	turned off via `--full-clone`.

abspath.c

@@ -12,7 +12,7 @@ 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)
+void strip_last_path_component(struct strbuf *path)
 {
 	size_t offset = offset_1st_component(path->buf);
 	size_t len = path->len;
@@ -117,7 +117,7 @@ static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
 			continue; /* '.' component */
 		} else if (next.len == 2 && !strcmp(next.buf, "..")) {
 			/* '..' component; strip the last path component */
-			strip_last_component(resolved);
+			strip_last_path_component(resolved);
 			continue;
 		}
 
@@ -169,7 +169,7 @@ static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
 				 * strip off the last component since it will
 				 * be replaced with the contents of the symlink
 				 */
-				strip_last_component(resolved);
+				strip_last_path_component(resolved);
 			}
 
 			/*

builtin/worktree.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "gvfs.h"
 #include "checkout.h"
 #include "config.h"
 #include "builtin.h"
@@ -1127,6 +1128,13 @@ int cmd_worktree(int ac, const char **av, const char *prefix)
 
 	git_config(git_worktree_config, NULL);
 
+	/*
+	 * git-worktree is special-cased to work in Scalar repositories
+	 * even when they use the GVFS Protocol.
+	 */
+	if (core_gvfs & GVFS_USE_VIRTUAL_FILESYSTEM)
+		die("'git %s' is not supported on a GVFS repo", "worktree");
+
 	if (!prefix)
 		prefix = "";
 

git.c

@@ -703,7 +703,7 @@ static struct cmd_struct commands[] = {
 	{ "verify-tag", cmd_verify_tag, RUN_SETUP },
 	{ "version", cmd_version },
 	{ "whatchanged", cmd_whatchanged, RUN_SETUP },
-	{ "worktree", cmd_worktree, RUN_SETUP | BLOCK_ON_GVFS_REPO },
+	{ "worktree", cmd_worktree, RUN_SETUP },
 	{ "write-tree", cmd_write_tree, RUN_SETUP },
 };
 

gvfs.h

@@ -14,7 +14,18 @@
 #define GVFS_SKIP_SHA_ON_INDEX                      (1 << 0)
 #define GVFS_BLOCK_COMMANDS                         (1 << 1)
 #define GVFS_MISSING_OK                             (1 << 2)
+
+/*
+ * This behavior of not deleting outside of the sparse-checkout
+ * is specific to the virtual filesystem support. It is only
+ * enabled by VFS for Git, and so can be used as an indicator
+ * that we are in a virtualized filesystem environment and not
+ * in a Scalar environment. This bit has two names to reflect
+ * that.
+ */
 #define GVFS_NO_DELETE_OUTSIDE_SPARSECHECKOUT       (1 << 3)
+#define GVFS_USE_VIRTUAL_FILESYSTEM                 (1 << 3)
+
 #define GVFS_FETCH_SKIP_REACHABILITY_AND_UPLOADPACK (1 << 4)
 #define GVFS_BLOCK_FILTERS_AND_EOL_CONVERSIONS      (1 << 6)
 #define GVFS_PREFETCH_DURING_FETCH		    (1 << 7)

path.h

@@ -179,6 +179,10 @@ const char *git_path_auto_merge(struct repository *r);
 const char *git_path_fetch_head(struct repository *r);
 const char *git_path_shallow(struct repository *r);
 
+/**
+ * Remove the last path component from 'path' except if 'path' is root.
+ */
+void strip_last_path_component(struct strbuf *path);
 
 int ends_with_path_components(const char *path, const char *components);
 

scalar.c

@@ -16,6 +16,7 @@
 #include "help.h"
 #include "json-parser.h"
 #include "remote.h"
+#include "path.h"
 
 static int is_unattended(void) {
 	return git_env_bool("Scalar_UNATTENDED", 0);
@@ -461,8 +462,13 @@ static char *default_cache_root(const char *root)
 {
 	const char *env;
 
-	if (is_unattended())
-		return xstrfmt("%s/.scalarCache", root);
+	if (is_unattended()) {
+		struct strbuf path = STRBUF_INIT;
+		strbuf_addstr(&path, root);
+		strip_last_path_component(&path);
+		strbuf_addstr(&path, "/.scalarCache");
+		return strbuf_detach(&path, NULL);
+	}
 
 #ifdef WIN32
 	(void)env;
@@ -685,6 +691,8 @@ static int cmd_clone(int argc, const char **argv)
 	int full_clone = 0, single_branch = 0, dummy = 0;
 	const char *cache_server_url = NULL, *local_cache_root = NULL;
 	char *default_cache_server_url = NULL, *local_cache_root_abs = NULL;
+	const char *enlistment_parent;
+	int no_src = 0;
 	struct option clone_options[] = {
 		OPT_STRING('b', "branch", &branch, N_("<branch>"),
 			   N_("branch to checkout after clone")),
@@ -693,6 +701,8 @@ static int cmd_clone(int argc, const char **argv)
 		OPT_BOOL(0, "single-branch", &single_branch,
 			 N_("only download metadata for the branch that will "
 			    "be checked out")),
+		OPT_BOOL(0, "no-src", &no_src,
+			 N_("skip creating a 'src' directory")),
 		OPT_STRING(0, "cache-server-url", &cache_server_url,
 			   N_("<url>"),
 			   N_("the url or friendly name of the cache server")),
@@ -743,7 +753,13 @@ static int cmd_clone(int argc, const char **argv)
 
 	ensure_absolute_path(enlistment, &enlistment);
 
+	if (!no_src) {
 		dir = xstrfmt("%s/src", enlistment);
+		enlistment_parent = "../..";
+	} else {
+		dir = xstrdup(enlistment);
+		enlistment_parent = "..";
+	}
 
 	if (!local_cache_root)
 		local_cache_root = local_cache_root_abs =
@@ -784,7 +800,7 @@ static int cmd_clone(int argc, const char **argv)
 		struct strbuf path = STRBUF_INIT;
 
 		strbuf_addstr(&path, enlistment);
-		if (chdir("../..") < 0 ||
+		if (chdir(enlistment_parent) < 0 ||
 		    remove_dir_recursively(&path, 0) < 0)
 			die(_("'--local-cache-path' cannot be inside the src "
 			      "folder;\nCould not remove '%s'"), enlistment);

t/t9210-scalar.sh

@@ -282,7 +282,7 @@ test_expect_success '`scalar clone` with GVFS-enabled server' '
 	cache_key="url_$(printf "%s" http://$HOST_PORT/ |
 		tr A-Z a-z |
 		test-tool sha1)" &&
-	echo "$(pwd)/using-gvfs/.scalarCache/$cache_key" >expect &&
+	echo "$(pwd)/.scalarCache/$cache_key" >expect &&
 	git -C using-gvfs/src config gvfs.sharedCache >actual &&
 	test_cmp expect actual &&
 
@@ -367,4 +367,12 @@ test_expect_success '`scalar delete` with existing repo' '
 	test_path_is_missing existing
 '
 
+test_expect_success '`scalar clone --no-src`' '
+	scalar clone --src "file://$(pwd)" with-src &&
+	scalar clone --no-src "file://$(pwd)" without-src &&
+
+	test_path_is_dir with-src/src &&
+	test_path_is_missing without-src/src
+'
+
 test_done