rebase: start implementing it as a builtin
This commit imitates the strategy that was used to convert the
difftool to a builtin. We start by renaming the shell script
`git-rebase.sh` to `git-legacy-rebase.sh` and introduce a
`builtin/rebase.c` that simply executes the shell script version,
unless the config setting `rebase.useBuiltin` is set to `true`.
The motivation behind this is to rewrite all the functionality of the
shell script version in the aforementioned `rebase.c`, one by one and
be able to conveniently test new features by configuring
`rebase.useBuiltin`.
In the original difftool conversion, if sane_execvp() that attempts to
run the legacy scripted version returned with non-negative status, the
command silently exited without doing anything with success, but
sane_execvp() should not return with non-negative status in the first
place, so we use die() to notice such an abnormal case.
We intentionally avoid reading the config directly to avoid
messing up the GIT_* environment variables when we need to fall back to
exec()ing the shell script. The test of builtin rebase can be done by
`git -c rebase.useBuiltin=true rebase ...`
Signed-off-by: Pratik Karki <predatoramigo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/rebase.c b/builtin/rebase.c
new file mode 100644
index 0000000..c44addb
--- /dev/null
+++ b/builtin/rebase.c
@@ -0,0 +1,58 @@
+/*
+ * "git rebase" builtin command
+ *
+ * Copyright (c) 2018 Pratik Karki
+ */
+
+#include "builtin.h"
+#include "run-command.h"
+#include "exec-cmd.h"
+#include "argv-array.h"
+#include "dir.h"
+
+static int use_builtin_rebase(void)
+{
+ struct child_process cp = CHILD_PROCESS_INIT;
+ struct strbuf out = STRBUF_INIT;
+ int ret;
+
+ argv_array_pushl(&cp.args,
+ "config", "--bool", "rebase.usebuiltin", NULL);
+ cp.git_cmd = 1;
+ if (capture_command(&cp, &out, 6)) {
+ strbuf_release(&out);
+ return 0;
+ }
+
+ strbuf_trim(&out);
+ ret = !strcmp("true", out.buf);
+ strbuf_release(&out);
+ return ret;
+}
+
+int cmd_rebase(int argc, const char **argv, const char *prefix)
+{
+ /*
+ * NEEDSWORK: Once the builtin rebase has been tested enough
+ * and git-legacy-rebase.sh is retired to contrib/, this preamble
+ * can be removed.
+ */
+
+ if (!use_builtin_rebase()) {
+ const char *path = mkpath("%s/git-legacy-rebase",
+ git_exec_path());
+
+ if (sane_execvp(path, (char **)argv) < 0)
+ die_errno(_("could not exec %s"), path);
+ else
+ BUG("sane_execvp() returned???");
+ }
+
+ if (argc != 2)
+ die(_("Usage: %s <base>"), argv[0]);
+ prefix = setup_git_directory();
+ trace_repo_setup(prefix);
+ setup_work_tree();
+
+ die("TODO");
+}
