From: Phillip Wood Date: Fri, 08 Oct 2021 11:09:30 GMT Subject: Re: [PATCH v3 6/8] reset: make sparse-aware (except --mixed) Message-ID: In-Reply-To: <330e0c0977480d0506801854fcaa6c9f2b014569.1633641339.git.gitgitgadget@gmail.com> Hi Victoria On 07/10/2021 22:15, Victoria Dye via GitGitGadget wrote: > From: Victoria Dye > > Remove `ensure_full_index` guard on `prime_cache_tree` and update > `prime_cache_tree_rec` to correctly reconstruct sparse directory entries in > the cache tree. While processing a tree's entries, `prime_cache_tree_rec` > must determine whether a directory entry is sparse or not by searching for > it in the index (*without* expanding the index). If a matching sparse > directory index entry is found, no subtrees are added to the cache tree > entry and the entry count is set to 1 (representing the sparse directory > itself). Otherwise, the tree is assumed to not be sparse and its subtrees > are recursively added to the cache tree. I was looking at the callers to prime_cache_tree() this morning and would like to suggest an alternative approach - just delete prime_cache_tree() and all of its callers! As far as I can see it is only ever called after a successful call to unpack_trees() and since 52fca2184d ("unpack-trees: populate cache-tree on successful merge", 2015-07-28) unpack_trees() updates the cache tree for the caller. All the call sites are pretty obvious apart from the one in t/help/test-fast-rebase.c where unpack_trees() is called by merge_switch_to_result() Best Wishes Phillip > Helped-by: Elijah Newren > Signed-off-by: Victoria Dye > --- > cache-tree.c | 47 ++++++++++++++++++++++-- > cache.h | 10 +++++ > read-cache.c | 27 ++++++++++---- > t/t1092-sparse-checkout-compatibility.sh | 15 +++++++- > 4 files changed, 86 insertions(+), 13 deletions(-) > > diff --git a/cache-tree.c b/cache-tree.c > index 9be19c85b66..2866101052c 100644 > --- a/cache-tree.c > +++ b/cache-tree.c > @@ -740,15 +740,26 @@ out: > return ret; > } > > +static void prime_cache_tree_sparse_dir(struct cache_tree *it, > + struct tree *tree) > +{ > + > + oidcpy(&it->oid, &tree->object.oid); > + it->entry_count = 1; > +} > + > static void prime_cache_tree_rec(struct repository *r, > struct cache_tree *it, > - struct tree *tree) > + struct tree *tree, > + struct strbuf *tree_path) > { > struct tree_desc desc; > struct name_entry entry; > int cnt; > + int base_path_len = tree_path->len; > > oidcpy(&it->oid, &tree->object.oid); > + > init_tree_desc(&desc, tree->buffer, tree->size); > cnt = 0; > while (tree_entry(&desc, &entry)) { > @@ -757,14 +768,40 @@ static void prime_cache_tree_rec(struct repository *r, > else { > struct cache_tree_sub *sub; > struct tree *subtree = lookup_tree(r, &entry.oid); > + > if (!subtree->object.parsed) > parse_tree(subtree); > sub = cache_tree_sub(it, entry.path); > sub->cache_tree = cache_tree(); > - prime_cache_tree_rec(r, sub->cache_tree, subtree); > + > + /* > + * Recursively-constructed subtree path is only needed when working > + * in a sparse index (where it's used to determine whether the > + * subtree is a sparse directory in the index). > + */ > + if (r->index->sparse_index) { > + strbuf_setlen(tree_path, base_path_len); > + strbuf_grow(tree_path, base_path_len + entry.pathlen + 1); > + strbuf_add(tree_path, entry.path, entry.pathlen); > + strbuf_addch(tree_path, '/'); > + } > + > + /* > + * If a sparse index is in use, the directory being processed may be > + * sparse. To confirm that, we can check whether an entry with that > + * exact name exists in the index. If it does, the created subtree > + * should be sparse. Otherwise, cache tree expansion should continue > + * as normal. > + */ > + if (r->index->sparse_index && > + index_entry_exists(r->index, tree_path->buf, tree_path->len)) > + prime_cache_tree_sparse_dir(sub->cache_tree, subtree); > + else > + prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path); > cnt += sub->cache_tree->entry_count; > } > } > + > it->entry_count = cnt; > } > > @@ -772,12 +809,14 @@ void prime_cache_tree(struct repository *r, > struct index_state *istate, > struct tree *tree) > { > + struct strbuf tree_path = STRBUF_INIT; > + > trace2_region_enter("cache-tree", "prime_cache_tree", the_repository); > cache_tree_free(&istate->cache_tree); > istate->cache_tree = cache_tree(); > > - ensure_full_index(istate); > - prime_cache_tree_rec(r, istate->cache_tree, tree); > + prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path); > + strbuf_release(&tree_path); > istate->cache_changed |= CACHE_TREE_CHANGED; > trace2_region_leave("cache-tree", "prime_cache_tree", the_repository); > } > diff --git a/cache.h b/cache.h > index f6295f3b048..1d3e4665562 100644 > --- a/cache.h > +++ b/cache.h > @@ -816,6 +816,16 @@ struct cache_entry *index_file_exists(struct index_state *istate, const char *na > */ > int index_name_pos(struct index_state *, const char *name, int namelen); > > +/* > + * Determines whether an entry with the given name exists within the > + * given index. The return value is 1 if an exact match is found, otherwise > + * it is 0. Note that, unlike index_name_pos, this function does not expand > + * the index if it is sparse. If an item exists within the full index but it > + * is contained within a sparse directory (and not in the sparse index), 0 is > + * returned. > + */ > +int index_entry_exists(struct index_state *, const char *name, int namelen); > + > /* > * Some functions return the negative complement of an insert position when a > * precise match was not found but a position was found where the entry would > diff --git a/read-cache.c b/read-cache.c > index f5d4385c408..c079ece981a 100644 > --- a/read-cache.c > +++ b/read-cache.c > @@ -68,6 +68,11 @@ > */ > #define CACHE_ENTRY_PATH_LENGTH 80 > > +enum index_search_mode { > + NO_EXPAND_SPARSE = 0, > + EXPAND_SPARSE = 1 > +}; > + > static inline struct cache_entry *mem_pool__ce_alloc(struct mem_pool *mem_pool, size_t len) > { > struct cache_entry *ce; > @@ -551,7 +556,10 @@ int cache_name_stage_compare(const char *name1, int len1, int stage1, const char > return 0; > } > > -static int index_name_stage_pos(struct index_state *istate, const char *name, int namelen, int stage) > +static int index_name_stage_pos(struct index_state *istate, > + const char *name, int namelen, > + int stage, > + enum index_search_mode search_mode) > { > int first, last; > > @@ -570,7 +578,7 @@ static int index_name_stage_pos(struct index_state *istate, const char *name, in > first = next+1; > } > > - if (istate->sparse_index && > + if (search_mode == EXPAND_SPARSE && istate->sparse_index && > first > 0) { > /* Note: first <= istate->cache_nr */ > struct cache_entry *ce = istate->cache[first - 1]; > @@ -586,7 +594,7 @@ static int index_name_stage_pos(struct index_state *istate, const char *name, in > ce_namelen(ce) < namelen && > !strncmp(name, ce->name, ce_namelen(ce))) { > ensure_full_index(istate); > - return index_name_stage_pos(istate, name, namelen, stage); > + return index_name_stage_pos(istate, name, namelen, stage, search_mode); > } > } > > @@ -595,7 +603,12 @@ static int index_name_stage_pos(struct index_state *istate, const char *name, in > > int index_name_pos(struct index_state *istate, const char *name, int namelen) > { > - return index_name_stage_pos(istate, name, namelen, 0); > + return index_name_stage_pos(istate, name, namelen, 0, EXPAND_SPARSE); > +} > + > +int index_entry_exists(struct index_state *istate, const char *name, int namelen) > +{ > + return index_name_stage_pos(istate, name, namelen, 0, NO_EXPAND_SPARSE) >= 0; > } > > int remove_index_entry_at(struct index_state *istate, int pos) > @@ -1222,7 +1235,7 @@ static int has_dir_name(struct index_state *istate, > */ > } > > - pos = index_name_stage_pos(istate, name, len, stage); > + pos = index_name_stage_pos(istate, name, len, stage, EXPAND_SPARSE); > if (pos >= 0) { > /* > * Found one, but not so fast. This could > @@ -1322,7 +1335,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e > strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0) > pos = index_pos_to_insert_pos(istate->cache_nr); > else > - pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce)); > + pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce), EXPAND_SPARSE); > > /* existing match? Just replace it. */ > if (pos >= 0) { > @@ -1357,7 +1370,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e > if (!ok_to_replace) > return error(_("'%s' appears as both a file and as a directory"), > ce->name); > - pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce)); > + pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce), EXPAND_SPARSE); > pos = -pos-1; > } > return pos + 1; > diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh > index 875cdcb0495..4ac93874cb2 100755 > --- a/t/t1092-sparse-checkout-compatibility.sh > +++ b/t/t1092-sparse-checkout-compatibility.sh > @@ -756,9 +756,9 @@ test_expect_success 'sparse-index is not expanded' ' > ensure_not_expanded checkout - && > ensure_not_expanded switch rename-out-to-out && > ensure_not_expanded switch - && > - git -C sparse-index reset --hard && > + ensure_not_expanded reset --hard && > ensure_not_expanded checkout rename-out-to-out -- deep/deeper1 && > - git -C sparse-index reset --hard && > + ensure_not_expanded reset --hard && > ensure_not_expanded restore -s rename-out-to-out -- deep/deeper1 && > > echo >>sparse-index/README.md && > @@ -768,6 +768,17 @@ test_expect_success 'sparse-index is not expanded' ' > echo >>sparse-index/untracked.txt && > ensure_not_expanded add . && > > + for ref in update-deep update-folder1 update-folder2 update-deep > + do > + echo >>sparse-index/README.md && > + ensure_not_expanded reset --hard $ref || return 1 > + done && > + > + ensure_not_expanded reset --hard update-deep && > + ensure_not_expanded reset --keep base && > + ensure_not_expanded reset --merge update-deep && > + ensure_not_expanded reset --hard && > + > ensure_not_expanded checkout -f update-deep && > test_config -C sparse-index pull.twohead ort && > ( >