From: Han-Wen Nienhuys <hanwen@xxxxxxxxxx>
When set in the environment, GIT_TRACE_REFS makes git print operations and
results as they flow through the ref storage backend. This helps debug
discrepancies between different ref backends.
Example:
$ GIT_TRACE_REFS="1" ./git branch
15:42:09.769631 refs/debug.c:26 ref_store for .git
15:42:09.769681 refs/debug.c:249 read_raw_ref: HEAD: 0000000000000000000000000000000000000000 (=> refs/heads/ref-debug) type 1: 0
15:42:09.769695 refs/debug.c:249 read_raw_ref: refs/heads/ref-debug: 3a238e539bcdfe3f9eb5010fd218640c1b499f7a (=> refs/heads/ref-debug) type 0: 0
15:42:09.770282 refs/debug.c:233 ref_iterator_begin: refs/heads/ (0x1)
15:42:09.770290 refs/debug.c:189 iterator_advance: refs/heads/b4 (0)
15:42:09.770295 refs/debug.c:189 iterator_advance: refs/heads/branch3 (0)
Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx>
---
refs: add GIT_TRACE_REFS debugging mechanism
When set in the environment, GIT_TRACE_REFS makes git print operations
and results as they flow through the ref storage backend. This helps
debug discrepancies between different ref backends.
cc: Jonathan Tan jonathantanmy@xxxxxxxxxx [jonathantanmy@xxxxxxxxxx]cc:
Jonathan Nieder jrnieder@xxxxxxxxx [jrnieder@xxxxxxxxx]cc: Jeff King
peff@xxxxxxxx [peff@xxxxxxxx]cc: Han-Wen Nienhuys hanwen@xxxxxxxxxx
[hanwen@xxxxxxxxxx]
v3: use xstrdup to copy backend name; I forgot to commit this bit in the
last round.
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-713%2Fhanwen%2Fdebug-refs-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-713/hanwen/debug-refs-v4
Pull-Request: https://github.com/gitgitgadget/git/pull/713
Range-diff vs v3:
1: e19e2a3433 ! 1: e73293f0f7 refs: add GIT_TRACE_REFS debugging mechanism
@@ refs/debug.c (new)
+ res = xmalloc(sizeof(struct debug_ref_store));
+ be_copy = xmalloc(sizeof(*be_copy));
+ *be_copy = refs_be_debug;
-+ /* we never deallocate backends, so safe to copy the pointer. */
-+ be_copy->name = store->be->name;
++ be_copy->name = xstrdup(store->be->name);
+ trace_printf_key(&trace_refs, "ref_store for %s\n", gitdir);
+ res->refs = store;
+ base_ref_store_init((struct ref_store *)res, be_copy);
Documentation/git.txt | 4 +
Makefile | 1 +
refs.c | 1 +
refs/debug.c | 397 ++++++++++++++++++++++++++++++++++++++++++
refs/refs-internal.h | 5 +
5 files changed, 408 insertions(+)
create mode 100644 refs/debug.c
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 2f72b10224..c463b937a8 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -722,6 +722,10 @@ of clones and fetches.
time of each Git command.
See `GIT_TRACE` for available trace output options.
+`GIT_TRACE_REFS`::
+ Enables trace messages for operations on the ref database.
+ See `GIT_TRACE` for available trace output options.
+
`GIT_TRACE_SETUP`::
Enables trace messages printing the .git, working tree and current
working directory after Git has completed its setup phase.
diff --git a/Makefile b/Makefile
index 86e5411f39..583b8c526e 100644
--- a/Makefile
+++ b/Makefile
@@ -950,6 +950,7 @@ LIB_OBJS += rebase.o
LIB_OBJS += ref-filter.o
LIB_OBJS += reflog-walk.o
LIB_OBJS += refs.o
+LIB_OBJS += refs/debug.o
LIB_OBJS += refs/files-backend.o
LIB_OBJS += refs/iterator.o
LIB_OBJS += refs/packed-backend.o
diff --git a/refs.c b/refs.c
index 156fdcd459..5febfe2281 100644
--- a/refs.c
+++ b/refs.c
@@ -1774,6 +1774,7 @@ struct ref_store *get_main_ref_store(struct repository *r)
BUG("attempting to get main_ref_store outside of repository");
r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
+ r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
return r->refs_private;
}
diff --git a/refs/debug.c b/refs/debug.c
new file mode 100644
index 0000000000..6588a556d0
--- /dev/null
+++ b/refs/debug.c
@@ -0,0 +1,397 @@
+
+#include "refs-internal.h"
+#include "trace.h"
+
+static struct trace_key trace_refs = TRACE_KEY_INIT(REFS);
+
+struct debug_ref_store {
+ struct ref_store base;
+ struct ref_store *refs;
+};
+
+extern struct ref_storage_be refs_be_debug;
+
+struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store)
+{
+ struct debug_ref_store *res;
+ struct ref_storage_be *be_copy;
+
+ if (!trace_want(&trace_refs)) {
+ return store;
+ }
+ res = xmalloc(sizeof(struct debug_ref_store));
+ be_copy = xmalloc(sizeof(*be_copy));
+ *be_copy = refs_be_debug;
+ be_copy->name = xstrdup(store->be->name);
+ trace_printf_key(&trace_refs, "ref_store for %s\n", gitdir);
+ res->refs = store;
+ base_ref_store_init((struct ref_store *)res, be_copy);
+ return (struct ref_store *)res;
+}
+
+static int debug_init_db(struct ref_store *refs, struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ int res = drefs->refs->be->init_db(drefs->refs, err);
+ trace_printf_key(&trace_refs, "init_db: %d\n", res);
+ return res;
+}
+
+static int debug_transaction_prepare(struct ref_store *refs,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ int res;
+ transaction->ref_store = drefs->refs;
+ res = drefs->refs->be->transaction_prepare(drefs->refs, transaction,
+ err);
+ trace_printf_key(&trace_refs, "transaction_prepare: %d\n", res);
+ return res;
+}
+
+static void print_update(int i, const char *refname,
+ const struct object_id *old_oid,
+ const struct object_id *new_oid, unsigned int flags,
+ unsigned int type, const char *msg)
+{
+ char o[GIT_MAX_HEXSZ + 1] = "null";
+ char n[GIT_MAX_HEXSZ + 1] = "null";
+ if (old_oid)
+ oid_to_hex_r(o, old_oid);
+ if (new_oid)
+ oid_to_hex_r(n, new_oid);
+
+ type &= 0xf; /* see refs.h REF_* */
+ flags &= REF_HAVE_NEW | REF_HAVE_OLD | REF_NO_DEREF |
+ REF_FORCE_CREATE_REFLOG;
+ trace_printf_key(&trace_refs, "%d: %s %s -> %s (F=0x%x, T=0x%x) \"%s\"\n", i, refname,
+ o, n, flags, type, msg);
+}
+
+static void print_transaction(struct ref_transaction *transaction)
+{
+ int i;
+ trace_printf_key(&trace_refs, "transaction {\n");
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *u = transaction->updates[i];
+ print_update(i, u->refname, &u->old_oid, &u->new_oid, u->flags,
+ u->type, u->msg);
+ }
+ trace_printf_key(&trace_refs, "}\n");
+}
+
+static int debug_transaction_finish(struct ref_store *refs,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ int res;
+ transaction->ref_store = drefs->refs;
+ res = drefs->refs->be->transaction_finish(drefs->refs, transaction,
+ err);
+ print_transaction(transaction);
+ trace_printf_key(&trace_refs, "finish: %d\n", res);
+ return res;
+}
+
+static int debug_transaction_abort(struct ref_store *refs,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ int res;
+ transaction->ref_store = drefs->refs;
+ res = drefs->refs->be->transaction_abort(drefs->refs, transaction, err);
+ return res;
+}
+
+static int debug_initial_transaction_commit(struct ref_store *refs,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ int res;
+ transaction->ref_store = drefs->refs;
+ res = drefs->refs->be->initial_transaction_commit(drefs->refs,
+ transaction, err);
+ return res;
+}
+
+static int debug_pack_refs(struct ref_store *ref_store, unsigned int flags)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->pack_refs(drefs->refs, flags);
+ trace_printf_key(&trace_refs, "pack_refs: %d\n", res);
+ return res;
+}
+
+static int debug_create_symref(struct ref_store *ref_store,
+ const char *ref_name, const char *target,
+ const char *logmsg)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->create_symref(drefs->refs, ref_name, target,
+ logmsg);
+ trace_printf_key(&trace_refs, "create_symref: %s -> %s \"%s\": %d\n", ref_name,
+ target, logmsg, res);
+ return res;
+}
+
+static int debug_delete_refs(struct ref_store *ref_store, const char *msg,
+ struct string_list *refnames, unsigned int flags)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res =
+ drefs->refs->be->delete_refs(drefs->refs, msg, refnames, flags);
+ int i;
+ trace_printf_key(&trace_refs, "delete_refs {\n");
+ for (i = 0; i < refnames->nr; i++)
+ trace_printf_key(&trace_refs, "%s\n", refnames->items[i].string);
+ trace_printf_key(&trace_refs, "}: %d\n", res);
+ return res;
+}
+
+static int debug_rename_ref(struct ref_store *ref_store, const char *oldref,
+ const char *newref, const char *logmsg)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->rename_ref(drefs->refs, oldref, newref,
+ logmsg);
+ trace_printf_key(&trace_refs, "rename_ref: %s -> %s \"%s\": %d\n", oldref, newref,
+ logmsg, res);
+ return res;
+}
+
+static int debug_copy_ref(struct ref_store *ref_store, const char *oldref,
+ const char *newref, const char *logmsg)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res =
+ drefs->refs->be->copy_ref(drefs->refs, oldref, newref, logmsg);
+ trace_printf_key(&trace_refs, "copy_ref: %s -> %s \"%s\": %d\n", oldref, newref,
+ logmsg, res);
+ return res;
+}
+
+struct debug_ref_iterator {
+ struct ref_iterator base;
+ struct ref_iterator *iter;
+};
+
+static int debug_ref_iterator_advance(struct ref_iterator *ref_iterator)
+{
+ struct debug_ref_iterator *diter =
+ (struct debug_ref_iterator *)ref_iterator;
+ int res = diter->iter->vtable->advance(diter->iter);
+ if (res)
+ trace_printf_key(&trace_refs, "iterator_advance: (%d)\n", res);
+ else
+ trace_printf_key(&trace_refs, "iterator_advance: %s (0)\n",
+ diter->iter->refname);
+
+ diter->base.ordered = diter->iter->ordered;
+ diter->base.refname = diter->iter->refname;
+ diter->base.oid = diter->iter->oid;
+ diter->base.flags = diter->iter->flags;
+ return res;
+}
+
+static int debug_ref_iterator_peel(struct ref_iterator *ref_iterator,
+ struct object_id *peeled)
+{
+ struct debug_ref_iterator *diter =
+ (struct debug_ref_iterator *)ref_iterator;
+ int res = diter->iter->vtable->peel(diter->iter, peeled);
+ trace_printf_key(&trace_refs, "iterator_peel: %s: %d\n", diter->iter->refname, res);
+ return res;
+}
+
+static int debug_ref_iterator_abort(struct ref_iterator *ref_iterator)
+{
+ struct debug_ref_iterator *diter =
+ (struct debug_ref_iterator *)ref_iterator;
+ int res = diter->iter->vtable->abort(diter->iter);
+ trace_printf_key(&trace_refs, "iterator_abort: %d\n", res);
+ return res;
+}
+
+static struct ref_iterator_vtable debug_ref_iterator_vtable = {
+ debug_ref_iterator_advance, debug_ref_iterator_peel,
+ debug_ref_iterator_abort
+};
+
+static struct ref_iterator *
+debug_ref_iterator_begin(struct ref_store *ref_store, const char *prefix,
+ unsigned int flags)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ struct ref_iterator *res =
+ drefs->refs->be->iterator_begin(drefs->refs, prefix, flags);
+ struct debug_ref_iterator *diter = xcalloc(1, sizeof(*diter));
+ base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable, 1);
+ diter->iter = res;
+ trace_printf_key(&trace_refs, "ref_iterator_begin: %s (0x%x)\n", prefix, flags);
+ return &diter->base;
+}
+
+static int debug_read_raw_ref(struct ref_store *ref_store, const char *refname,
+ struct object_id *oid, struct strbuf *referent,
+ unsigned int *type)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = 0;
+
+ oidcpy(oid, &null_oid);
+ res = drefs->refs->be->read_raw_ref(drefs->refs, refname, oid, referent,
+ type);
+
+ if (res == 0) {
+ trace_printf_key(&trace_refs, "read_raw_ref: %s: %s (=> %s) type %x: %d\n",
+ refname, oid_to_hex(oid), referent->buf, *type, res);
+ } else {
+ trace_printf_key(&trace_refs, "read_raw_ref: %s: %d\n", refname, res);
+ }
+ return res;
+}
+
+static struct ref_iterator *
+debug_reflog_iterator_begin(struct ref_store *ref_store)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ struct ref_iterator *res =
+ drefs->refs->be->reflog_iterator_begin(drefs->refs);
+ trace_printf_key(&trace_refs, "for_each_reflog_iterator_begin\n");
+ return res;
+}
+
+struct debug_reflog {
+ const char *refname;
+ each_reflog_ent_fn *fn;
+ void *cb_data;
+};
+
+static int debug_print_reflog_ent(struct object_id *old_oid,
+ struct object_id *new_oid,
+ const char *committer, timestamp_t timestamp,
+ int tz, const char *msg, void *cb_data)
+{
+ struct debug_reflog *dbg = (struct debug_reflog *)cb_data;
+ int ret;
+ char o[GIT_MAX_HEXSZ + 1] = "null";
+ char n[GIT_MAX_HEXSZ + 1] = "null";
+ if (old_oid)
+ oid_to_hex_r(o, old_oid);
+ if (new_oid)
+ oid_to_hex_r(n, new_oid);
+
+ ret = dbg->fn(old_oid, new_oid, committer, timestamp, tz, msg,
+ dbg->cb_data);
+ trace_printf_key(&trace_refs, "reflog_ent %s (ret %d): %s -> %s, %s %ld \"%s\"\n",
+ dbg->refname, ret, o, n, committer, (long int)timestamp, msg);
+ return ret;
+}
+
+static int debug_for_each_reflog_ent(struct ref_store *ref_store,
+ const char *refname, each_reflog_ent_fn fn,
+ void *cb_data)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ struct debug_reflog dbg = {
+ .refname = refname,
+ .fn = fn,
+ .cb_data = cb_data,
+ };
+
+ int res = drefs->refs->be->for_each_reflog_ent(
+ drefs->refs, refname, &debug_print_reflog_ent, &dbg);
+ trace_printf_key(&trace_refs, "for_each_reflog: %s: %d\n", refname, res);
+ return res;
+}
+
+static int debug_for_each_reflog_ent_reverse(struct ref_store *ref_store,
+ const char *refname,
+ each_reflog_ent_fn fn,
+ void *cb_data)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ struct debug_reflog dbg = {
+ .refname = refname,
+ .fn = fn,
+ .cb_data = cb_data,
+ };
+ int res = drefs->refs->be->for_each_reflog_ent_reverse(
+ drefs->refs, refname, &debug_print_reflog_ent, &dbg);
+ trace_printf_key(&trace_refs, "for_each_reflog_reverse: %s: %d\n", refname, res);
+ return res;
+}
+
+static int debug_reflog_exists(struct ref_store *ref_store, const char *refname)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->reflog_exists(drefs->refs, refname);
+ trace_printf_key(&trace_refs, "reflog_exists: %s: %d\n", refname, res);
+ return res;
+}
+
+static int debug_create_reflog(struct ref_store *ref_store, const char *refname,
+ int force_create, struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->create_reflog(drefs->refs, refname,
+ force_create, err);
+ trace_printf_key(&trace_refs, "create_reflog: %s: %d\n", refname, res);
+ return res;
+}
+
+static int debug_delete_reflog(struct ref_store *ref_store, const char *refname)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->delete_reflog(drefs->refs, refname);
+ trace_printf_key(&trace_refs, "delete_reflog: %s: %d\n", refname, res);
+ return res;
+}
+
+static int debug_reflog_expire(struct ref_store *ref_store, const char *refname,
+ const struct object_id *oid, unsigned int flags,
+ reflog_expiry_prepare_fn prepare_fn,
+ reflog_expiry_should_prune_fn should_prune_fn,
+ reflog_expiry_cleanup_fn cleanup_fn,
+ void *policy_cb_data)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+ int res = drefs->refs->be->reflog_expire(drefs->refs, refname, oid,
+ flags, prepare_fn,
+ should_prune_fn, cleanup_fn,
+ policy_cb_data);
+ trace_printf_key(&trace_refs, "reflog_expire: %s: %d\n", refname, res);
+ return res;
+}
+
+struct ref_storage_be refs_be_debug = {
+ NULL,
+ "debug",
+ NULL,
+ debug_init_db,
+ debug_transaction_prepare,
+ debug_transaction_finish,
+ debug_transaction_abort,
+ debug_initial_transaction_commit,
+
+ debug_pack_refs,
+ debug_create_symref,
+ debug_delete_refs,
+ debug_rename_ref,
+ debug_copy_ref,
+
+ debug_ref_iterator_begin,
+ debug_read_raw_ref,
+
+ debug_reflog_iterator_begin,
+ debug_for_each_reflog_ent,
+ debug_for_each_reflog_ent_reverse,
+ debug_reflog_exists,
+ debug_create_reflog,
+ debug_delete_reflog,
+ debug_reflog_expire,
+};
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 527b0a6e2e..fecde40baf 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -690,4 +690,9 @@ int parse_loose_ref_contents(const char *buf, struct object_id *oid,
void base_ref_store_init(struct ref_store *refs,
const struct ref_storage_be *be);
+/*
+ * Support GIT_TRACE_REFS by optionally wrapping the given ref_store instance.
+ */
+struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store);
+
#endif /* REFS_REFS_INTERNAL_H */
base-commit: 3a238e539bcdfe3f9eb5010fd218640c1b499f7a
--
gitgitgadget
