unittests: Add tv_dict_add* unit tests

Also fixes incorrect location of `tv_dict_add` function and three bugs in other 
functions:

1. `tv_dict_add_list` may free list it does not own (vim/vim#1555).
2. `tv_dict_add_dict` may free dictionary it does not own (vim/vim#1555).
3. `tv_dict_add_dict` ignores `key_len` argument.

2 files changed, 132 insertions, 16 deletions

diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 867330c137..d9feb2d88e 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -1009,18 +1009,6 @@ void tv_dict_item_free(dictitem_T *const item)
   }
 }
 
-/// Add item to dictionary
-///
-/// @param[out]  d  Dictionary to add to.
-/// @param[in]  item  Item to add.
-///
-/// @return FAIL if key already exists.
-int tv_dict_add(dict_T *const d, dictitem_T *const item)
-  FUNC_ATTR_NONNULL_ALL
-{
-  return hash_add(&d->dv_hashtab, item->di_key);
-}
-
 /// Make a copy of a dictionary item
 ///
 /// @param[in]  di  Item to copy.
@@ -1278,6 +1266,18 @@ bool tv_dict_get_callback(dict_T *const d,
 
 //{{{2 dict_add*
 
+/// Add item to dictionary
+///
+/// @param[out]  d  Dictionary to add to.
+/// @param[in]  item  Item to add.
+///
+/// @return FAIL if key already exists.
+int tv_dict_add(dict_T *const d, dictitem_T *const item)
+  FUNC_ATTR_NONNULL_ALL
+{
+  return hash_add(&d->dv_hashtab, item->di_key);
+}
+
 /// Add a list entry to dictionary
 ///
 /// @param[out]  d  Dictionary to add entry to.
@@ -1295,11 +1295,11 @@ int tv_dict_add_list(dict_T *const d, const char *const key,
   item->di_tv.v_lock = VAR_UNLOCKED;
   item->di_tv.v_type = VAR_LIST;
   item->di_tv.vval.v_list = list;
+  list->lv_refcount++;
   if (tv_dict_add(d, item) == FAIL) {
     tv_dict_item_free(item);
     return FAIL;
   }
-  list->lv_refcount++;
   return OK;
 }
 
@@ -1313,18 +1313,18 @@ int tv_dict_add_list(dict_T *const d, const char *const key,
 /// @return OK in case of success, FAIL when key already exists.
 int tv_dict_add_dict(dict_T *const d, const char *const key,
                      const size_t key_len, dict_T *const dict)
-    FUNC_ATTR_NONNULL_ALL
+  FUNC_ATTR_NONNULL_ALL
 {
-  dictitem_T *const item = tv_dict_item_alloc(key);
+  dictitem_T *const item = tv_dict_item_alloc_len(key, key_len);
 
   item->di_tv.v_lock = VAR_UNLOCKED;
   item->di_tv.v_type = VAR_DICT;
   item->di_tv.vval.v_dict = dict;
+  dict->dv_refcount++;
   if (tv_dict_add(d, item) == FAIL) {
     tv_dict_item_free(item);
     return FAIL;
   }
-  dict->dv_refcount++;
   return OK;
 }
 
diff --git a/test/unit/eval/typval_spec.lua b/test/unit/eval/typval_spec.lua
index d91fd3e78d..c710171779 100644
--- a/test/unit/eval/typval_spec.lua
+++ b/test/unit/eval/typval_spec.lua
@@ -1770,6 +1770,122 @@ describe('typval.c', function()
              {tv_dict_get_callback(d, 'testt', 5)})
         end)
       end)
+      describe('dict_add()', function()
+        itp('works', function()
+          local di = lib.tv_dict_item_alloc_len('t-est', 5)
+          alloc_log:check({a.di(di, 't-est')})
+          di.di_tv.v_type = lib.VAR_NUMBER
+          di.di_tv.vval.v_number = 42
+          local d = dict({test=10})
+          local dis = dict_items(d)
+          alloc_log:check({
+            a.dict(d),
+            a.di(dis.test, 'test')
+          })
+          eq({test=10}, dct2tbl(d))
+          alloc_log:clear()
+          eq(OK, lib.tv_dict_add(d, di))
+          alloc_log:check({})
+          eq({test=10, ['t-est']=int(42)}, dct2tbl(d))
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add(d, di) end,
+                              'E685: Internal error: hash_add()'))
+        end)
+      end)
+      describe('dict_add_list()', function()
+        itp('works', function()
+          local l = list(1, 2, 3)
+          alloc_log:clear()
+          eq(1, l.lv_refcount)
+          local d = dict({test=10})
+          alloc_log:clear()
+          eq({test=10}, dct2tbl(d))
+          eq(OK, lib.tv_dict_add_list(d, 'testt', 3, l))
+          local dis = dict_items(d)
+          alloc_log:check({a.di(dis.tes, 'tes')})
+          eq({test=10, tes={1, 2, 3}}, dct2tbl(d))
+          eq(2, l.lv_refcount)
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_list(d, 'testt', 3, l) end,
+                              'E685: Internal error: hash_add()'))
+          eq(2, l.lv_refcount)
+          alloc_log:clear()
+          lib.emsg_skip = lib.emsg_skip + 1
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_list(d, 'testt', 3, l) end,
+                              nil))
+          eq(2, l.lv_refcount)
+          lib.emsg_skip = lib.emsg_skip - 1
+          alloc_log:clear_tmp_allocs()
+          alloc_log:check({})
+        end)
+      end)
+      describe('dict_add_dict()', function()
+        itp('works', function()
+          local d2 = dict({foo=42})
+          alloc_log:clear()
+          eq(1, d2.dv_refcount)
+          local d = dict({test=10})
+          alloc_log:clear()
+          eq({test=10}, dct2tbl(d))
+          eq(OK, lib.tv_dict_add_dict(d, 'testt', 3, d2))
+          local dis = dict_items(d)
+          alloc_log:check({a.di(dis.tes, 'tes')})
+          eq({test=10, tes={foo=42}}, dct2tbl(d))
+          eq(2, d2.dv_refcount)
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_dict(d, 'testt', 3, d2) end,
+                              'E685: Internal error: hash_add()'))
+          eq(2, d2.dv_refcount)
+          alloc_log:clear()
+          lib.emsg_skip = lib.emsg_skip + 1
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_dict(d, 'testt', 3, d2) end,
+                              nil))
+          eq(2, d2.dv_refcount)
+          lib.emsg_skip = lib.emsg_skip - 1
+          alloc_log:clear_tmp_allocs()
+          alloc_log:check({})
+        end)
+      end)
+      describe('dict_add_nr()', function()
+        itp('works', function()
+          local d = dict({test=10})
+          alloc_log:clear()
+          eq({test=10}, dct2tbl(d))
+          eq(OK, lib.tv_dict_add_nr(d, 'testt', 3, 2))
+          local dis = dict_items(d)
+          alloc_log:check({a.di(dis.tes, 'tes')})
+          eq({test=10, tes=int(2)}, dct2tbl(d))
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_nr(d, 'testt', 3, 2) end,
+                              'E685: Internal error: hash_add()'))
+          alloc_log:clear()
+          lib.emsg_skip = lib.emsg_skip + 1
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_nr(d, 'testt', 3, 2) end,
+                              nil))
+          lib.emsg_skip = lib.emsg_skip - 1
+          alloc_log:clear_tmp_allocs()
+          alloc_log:check({})
+        end)
+      end)
+      describe('dict_add_str()', function()
+        itp('works', function()
+          local d = dict({test=10})
+          alloc_log:clear()
+          eq({test=10}, dct2tbl(d))
+          eq(OK, lib.tv_dict_add_str(d, 'testt', 3, 'TEST'))
+          local dis = dict_items(d)
+          alloc_log:check({
+            a.di(dis.tes, 'tes'),
+            a.str(dis.tes.di_tv.vval.v_string, 'TEST')
+          })
+          eq({test=10, tes='TEST'}, dct2tbl(d))
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_str(d, 'testt', 3, 'TEST') end,
+                              'E685: Internal error: hash_add()'))
+          alloc_log:clear()
+          lib.emsg_skip = lib.emsg_skip + 1
+          eq(FAIL, check_emsg(function() return lib.tv_dict_add_str(d, 'testt', 3, 'TEST') end,
+                              nil))
+          lib.emsg_skip = lib.emsg_skip - 1
+          alloc_log:clear_tmp_allocs()
+          alloc_log:check({})
+        end)
+      end)
     end)
   end)
 end)