From 1ec166ee597641ef612b281b85f61a78b318b89b Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Mon, 8 Aug 2016 15:41:09 -0400
Subject: [PATCH] prune: Retain the tip of each ref even with date pruning

I hit an error with [CAHC](https://wiki.centos.org/SpecialInterestGroup/Atomic/Devel)
where we were doing time-based pruning.  `ostree summary -u` started failing,
and it took me a bit to realize it was because we were pruning
even the tip of old branches, which I was not at all expecting,
and I don't think users will too.

Perhaps in the future we could add some sort of --prune-ref-tips or
something if people wanted it, but I doubt it.
---
 src/ostree/ot-builtin-prune.c | 20 ++++++++++++++++++++
 tests/test-prune.sh           | 16 +++++++++++-----
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/ostree/ot-builtin-prune.c b/src/ostree/ot-builtin-prune.c
index 0b843c9..b17e83b 100644
--- a/src/ostree/ot-builtin-prune.c
+++ b/src/ostree/ot-builtin-prune.c
@@ -84,6 +84,8 @@ delete_commit (OstreeRepo *repo, const char *commit_to_delete, GCancellable *can
 static gboolean
 prune_commits_keep_younger_than_date (OstreeRepo *repo, const char *date, GCancellable *cancellable, GError **error)
 {
+  g_autoptr(GHashTable) refs = NULL;
+  g_autoptr(GHashTable) ref_heads = g_hash_table_new (g_str_hash, g_str_equal);
   g_autoptr(GHashTable) objects = NULL;
   GHashTableIter hash_iter;
   gpointer key, value;
@@ -100,6 +102,21 @@ prune_commits_keep_younger_than_date (OstreeRepo *repo, const char *date, GCance
   if (!ot_enable_tombstone_commits (repo, error))
     goto out;
 
+  if (!ostree_repo_list_refs (repo, NULL, &refs, cancellable, error))
+    goto out;
+
+  /* We used to prune the HEAD of a given ref by default, but that's
+   * broken for for a few reasons.  One is that people may use branches as
+   * tags.  Second is that if we do it, we should be deleting the ref
+   * too, otherwise e.g. `summary -u` breaks trying to load it, etc.
+   */
+  g_hash_table_iter_init (&hash_iter, refs);
+  while (g_hash_table_iter_next (&hash_iter, &key, &value))
+    {
+      /* Value is lifecycle bound to refs */
+      g_hash_table_add (ref_heads, (char*)value);
+    }
+
   if (!ostree_repo_list_objects (repo, OSTREE_REPO_LIST_OBJECTS_ALL, &objects,
                                  cancellable, error))
     goto out;
@@ -119,6 +136,9 @@ prune_commits_keep_younger_than_date (OstreeRepo *repo, const char *date, GCance
       if (objtype != OSTREE_OBJECT_TYPE_COMMIT)
         continue;
 
+      if (g_hash_table_contains (ref_heads, checksum))
+        continue;
+
       if (!ostree_repo_load_variant (repo, OSTREE_OBJECT_TYPE_COMMIT, checksum,
                                      &commit, error))
         goto out;
diff --git a/tests/test-prune.sh b/tests/test-prune.sh
index d32edbc..5134d56 100755
--- a/tests/test-prune.sh
+++ b/tests/test-prune.sh
@@ -87,25 +87,31 @@ assert_file_has_content tombstonecommitcount "^1$"
 ${CMD_PREFIX} ostree prune --repo=repo --refs-only --depth=0 -v
 find repo/objects -name '*.commit' | wc -l > commitcount
 assert_file_has_content commitcount "^1$"
-${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="2010-10-29 12:43:29 +0000"
 ${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="2005-10-29 12:43:29 +0000"
+${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="2010-10-29 12:43:29 +0000"
 find repo/objects -name '*.commit' | wc -l > commitcount
 assert_file_has_content commitcount "^3$"
 ${CMD_PREFIX} ostree --repo=repo prune --keep-younger-than="2015-10-29 12:43:29 +0000"
 find repo/objects -name '*.commit' | wc -l > commitcount
-assert_file_has_content commitcount "^1$"
+assert_file_has_content commitcount "^2$"
 
 
 ${CMD_PREFIX} ostree prune --repo=repo --refs-only --depth=0 -v
 find repo/objects -name '*.commit' | wc -l > commitcount
-assert_file_has_content commitcount "^1$"
+assert_file_has_content commitcount "^2$"
 ${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="October 25 1985"
 ${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="October 21 2015"
 find repo/objects -name '*.commit' | wc -l > commitcount
-assert_file_has_content commitcount "^3$"
+assert_file_has_content commitcount "^4$"
 ${CMD_PREFIX} ostree --repo=repo prune --keep-younger-than="1 week ago"
 find repo/objects -name '*.commit' | wc -l > commitcount
-assert_file_has_content commitcount "^1$"
+assert_file_has_content commitcount "^2$"
+
+${CMD_PREFIX} ostree --repo=repo commit --branch=oldcommit tree --timestamp="2005-10-29 12:43:29 +0000"
+oldcommit_rev=$($OSTREE --repo=repo rev-parse oldcommit)
+$OSTREE ls ${oldcommit_rev}
+${CMD_PREFIX} ostree --repo=repo prune --keep-younger-than="1 week ago"
+$OSTREE ls ${oldcommit_rev}
 
 ${CMD_PREFIX} ostree --repo=repo pull --depth=-1 origin test
 ${CMD_PREFIX} ostree --repo=repo commit --branch=test -m test -s test tree --timestamp="November 05 1955"
-- 
2.7.4