Merge pull request #508: scalar reconfigure: help users remove buggy repos

When running 'scalar reconfigure -a', such as at install time, Scalar
has warning messages about the repository missing (or not containing a
.git directory). Failures can also happen while trying to modify the
repository-local config for that repository.

These warnings may seem confusing to users who don't understand what
they mean or how to stop them.

Add a warning that instructs the user how to remove the warning in
future installations.

Author: derrickstolee

cache.h

@@ -632,6 +632,29 @@ void set_git_work_tree(const char *tree);
 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 
 void setup_work_tree(void);
+
+/*
+ * discover_git_directory_reason() is similar to discover_git_directory(),
+ * except it returns an enum value instead. It is important to note that
+ * a zero-valued return here is actually GIT_DIR_NONE, which is different
+ * from discover_git_directory.
+ */
+enum discovery_result {
+	GIT_DIR_NONE = 0,
+	GIT_DIR_EXPLICIT,
+	GIT_DIR_DISCOVERED,
+	GIT_DIR_BARE,
+	/* these are errors */
+	GIT_DIR_HIT_CEILING = -1,
+	GIT_DIR_HIT_MOUNT_POINT = -2,
+	GIT_DIR_INVALID_GITFILE = -3,
+	GIT_DIR_INVALID_OWNERSHIP = -4,
+	GIT_DIR_INVALID_FORMAT = -5,
+	GIT_DIR_CWD_FAILURE = -6,
+};
+enum discovery_result discover_git_directory_reason(struct strbuf *commondir,
+						    struct strbuf *gitdir);
+
 /*
  * Find the commondir and gitdir of the repository that contains the current
  * working directory, without changing the working directory or other global
@@ -640,8 +663,12 @@ void setup_work_tree(void);
  * both have the same result appended to the buffer.  The return value is
  * either 0 upon success and non-zero if no repository was found.
  */
-int discover_git_directory(struct strbuf *commondir,
-			   struct strbuf *gitdir);
+static inline int discover_git_directory(struct strbuf *commondir,
+					 struct strbuf *gitdir)
+{
+	return discover_git_directory_reason(commondir, gitdir) <= 0;
+}
+
 const char *setup_git_directory_gently(int *);
 const char *setup_git_directory(void);
 char *prefix_path(const char *prefix, int len, const char *path);

scalar.c

@@ -1350,26 +1350,48 @@ static int cmd_reconfigure(int argc, const char **argv)
 	git_config(get_scalar_repos, &scalar_repos);
 
 	for (i = 0; i < scalar_repos.nr; i++) {
+		int failed = 0;
 		const char *dir = scalar_repos.items[i].string;
 
 		strbuf_reset(&commondir);
 		strbuf_reset(&gitdir);
 
 		if (chdir(dir) < 0) {
 			warning_errno(_("could not switch to '%s'"), dir);
-			res = -1;
-		} else if (discover_git_directory(&commondir, &gitdir) < 0) {
-			warning_errno(_("git repository gone in '%s'"), dir);
-			res = -1;
-		} else {
-			git_config_clear();
+			failed = -1;
+			goto loop_end;
+		}
+
+		switch (discover_git_directory_reason(&commondir, &gitdir)) {
+		case GIT_DIR_INVALID_OWNERSHIP:
+			warning(_("repository at '%s' has different owner"), dir);
+			failed = -1;
+			goto loop_end;
+
+		case GIT_DIR_DISCOVERED:
+			break;
+
+		default:
+			warning(_("repository not found in '%s'"), dir);
+			failed = -1;
+			break;
+		}
+
+		git_config_clear();
+
+		the_repository = &r;
+		r.commondir = commondir.buf;
+		r.gitdir = gitdir.buf;
 
-			the_repository = &r;
-			r.commondir = commondir.buf;
-			r.gitdir = gitdir.buf;
+		if (set_recommended_config(1) < 0)
+			failed = -1;
 
-			if (set_recommended_config(1) < 0)
-				res = -1;
+loop_end:
+		if (failed) {
+			res = failed;
+			warning(_("to unregister this repository from Scalar, run\n"
+				  "\tgit config --global --unset --fixed-value scalar.repo \"%s\""),
+				dir);
 		}
 	}
 

setup.c

@@ -1142,18 +1142,6 @@ static int ensure_valid_ownership(const char *path)
 	return data.is_safe;
 }
 
-enum discovery_result {
-	GIT_DIR_NONE = 0,
-	GIT_DIR_EXPLICIT,
-	GIT_DIR_DISCOVERED,
-	GIT_DIR_BARE,
-	/* these are errors */
-	GIT_DIR_HIT_CEILING = -1,
-	GIT_DIR_HIT_MOUNT_POINT = -2,
-	GIT_DIR_INVALID_GITFILE = -3,
-	GIT_DIR_INVALID_OWNERSHIP = -4
-};
-
 /*
  * We cannot decide in this function whether we are in the work tree or
  * not, since the config can only be read _after_ this function was called.
@@ -1269,21 +1257,22 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
 	}
 }
 
-int discover_git_directory(struct strbuf *commondir,
-			   struct strbuf *gitdir)
+enum discovery_result discover_git_directory_reason(struct strbuf *commondir,
+						    struct strbuf *gitdir)
 {
 	struct strbuf dir = STRBUF_INIT, err = STRBUF_INIT;
 	size_t gitdir_offset = gitdir->len, cwd_len;
 	size_t commondir_offset = commondir->len;
 	struct repository_format candidate = REPOSITORY_FORMAT_INIT;
+	enum discovery_result result;
 
 	if (strbuf_getcwd(&dir))
-		return -1;
+		return GIT_DIR_CWD_FAILURE;
 
 	cwd_len = dir.len;
-	if (setup_git_directory_gently_1(&dir, gitdir, 0) <= 0) {
+	if ((result = setup_git_directory_gently_1(&dir, gitdir, 0)) <= 0) {
 		strbuf_release(&dir);
-		return -1;
+		return result;
 	}
 
 	/*
@@ -1313,7 +1302,7 @@ int discover_git_directory(struct strbuf *commondir,
 		strbuf_setlen(commondir, commondir_offset);
 		strbuf_setlen(gitdir, gitdir_offset);
 		clear_repository_format(&candidate);
-		return -1;
+		return GIT_DIR_INVALID_FORMAT;
 	}
 
 	/* take ownership of candidate.partial_clone */
@@ -1322,7 +1311,7 @@ int discover_git_directory(struct strbuf *commondir,
 	candidate.partial_clone = NULL;
 
 	clear_repository_format(&candidate);
-	return 0;
+	return result;
 }
 
 const char *setup_git_directory_gently(int *nongit_ok)
@@ -1403,9 +1392,11 @@ const char *setup_git_directory_gently(int *nongit_ok)
 		*nongit_ok = 1;
 		break;
 	case GIT_DIR_NONE:
+	case GIT_DIR_CWD_FAILURE:
+	case GIT_DIR_INVALID_FORMAT:
 		/*
 		 * As a safeguard against setup_git_directory_gently_1 returning
-		 * this value, fallthrough to BUG. Otherwise it is possible to
+		 * these values, fallthrough to BUG. Otherwise it is possible to
 		 * set startup_info->have_repository to 1 when we did nothing to
 		 * find a repository.
 		 */