Remove experimental zeroskip database backend

It never was ready for production use, is not distributed
anymore in cyruslibs and is not developed further.

Makefile.am

@@ -1512,13 +1512,6 @@ endif
 lib_libcyrus_la_LIBADD = libcrc32.la ${LIB_SASL} $(SSL_LIBS) $(GCOV_LIBS) $(LIBM)
 lib_libcyrus_la_CFLAGS = $(AM_CFLAGS) $(CFLAG_VISIBILITY)
 
-if USE_ZEROSKIP
-lib_libcyrus_la_SOURCES += lib/cyrusdb_zeroskip.c
-lib_libcyrus_la_LIBADD += $(ZEROSKIP_LIBS)
-lib_libcyrus_la_CFLAGS += $(ZEROSKIP_CFLAGS)
-AM_CPPFLAGS += $(ZEROSKIP_CFLAGS)
-endif
-
 noinst_LTLIBRARIES += libcrc32.la
 libcrc32_la_SOURCES = lib/crc32.c
 libcrc32_la_CFLAGS = -O3 $(AM_CFLAGS) $(CFLAG_VISIBILITY)

bench/cyrdbbench.c

@@ -247,7 +247,7 @@ static void usage(const char *progname)
     printf("  -d, --db             the db to run the benchmarks on\n");
     printf("                       (if not provided, will create a new db)\n");
     printf("  -t, --backend        type of the db backend to run benchmarks on\n");
-    printf("                       Available Cyrus DB's: twoskip, zeroskip\n");
+    printf("                       Available Cyrus DB's: twoskip\n");
     printf("  -n, --numrecs        number of records to write[default: 1000]\n");
     printf("  -h, --help           display this help and exit\n");
 }
@@ -480,12 +480,11 @@ int main(int argc, char *argv[])
         goto done;
     }
 
-    if (strncmp(BACKEND, "twoskip", strlen("twoskip")) == 0 ||
-        strncmp(BACKEND, "zeroskip", strlen("zeroskip")) == 0) {
+    if (strncmp(BACKEND, "twoskip", strlen("twoskip")) == 0) {
         fprintf(stderr, "Running benchmarks for `%s` backend\n", BACKEND);
     } else {
         fprintf(stderr, "%s is not a valid CyrusDB backend. ", BACKEND);
-        fprintf(stderr, "Choose between `twoskip` or `zeroskip`.\n");
+        fprintf(stderr, "Only `twoskip` is supported.\n");
         ret = EXIT_FAILURE;
         goto done;
     }

changes/next/remove-zeroskip

@@ -0,0 +1,14 @@
+Description:
+
+Remove experimental zeroskip database backend.
+
+
+Config changes:
+
+Remove any use of zeroskip as database backend. This backend was experimental
+and is broken.
+
+
+Upgrade instructions:
+
+Reconstruct all databases that used the zeroskip backend.

configure.ac

@@ -1491,22 +1491,6 @@ PKG_CHECK_MODULES([ICU], [icu-i18n >= 55 icu-uc >= 55], [
 AC_SUBST([ICU_LIBS])
 AC_SUBST([ICU_CFLAGS])
 
-dnl
-dnl Check for zeroskip library, needed for zeroskip support
-dnl
-AC_ARG_WITH([zeroskip],
-	[AS_HELP_STRING([--without-zeroskip], [ignore presence of Zeroskip and disable it])],
-    [],
-    [with_zeroskip=yes])
-AS_IF([test "x$with_zeroskip" = "xyes"],
-	[ PKG_CHECK_MODULES([ZEROSKIP], [libzeroskip],
-		[ AC_DEFINE(HAVE_ZEROSKIP, [], [Do we have Zeroskip?])
-		  with_zeroskip=yes ],
-		with_zeroskip=no)])
-AC_SUBST([ZEROSKIP_LIBS])
-AC_SUBST([ZEROSKIP_CFLAGS])
-AM_CONDITIONAL([USE_ZEROSKIP], [test "x$with_zeroskip" = xyes])
-
 dnl
 dnl Check for chardet library, needed for charset detection support
 dnl
@@ -2632,7 +2616,6 @@ Database support:
    mysql:              $with_mysql
    postgresql:         $use_pgsql
    sqlite:             $use_sqlite
-   zeroskip:           $with_zeroskip
 
 Search engine:
    squat:              $enable_squat

cunit/aaa-db.testc

@@ -19,7 +19,7 @@ struct binary_result
     size_t datalen;
 };
 
-static const char *backend = CUNIT_PARAM("skiplist,flat,twoskip,zeroskip");
+static const char *backend = CUNIT_PARAM("skiplist,flat,twoskip");
 static char *filename;
 static char *filename2;
 
@@ -190,15 +190,6 @@ static char *make_basedir(const char * const *reldirs)
 
 static int skiptest()
 {
-    /* cunit.pl doesn't play nice with #ifdef'ed CUNIT_PARAMS */
-
-    if (!strcmp(backend, "zeroskip")) {
-#ifdef HAVE_ZEROSKIP
-        return 0;
-#else
-        return 1;
-#endif
-    }
     return 0;
 }
 

cunit/conversations.testc

@@ -1419,11 +1419,7 @@ static int set_up(void)
     );
 
     cyrusdb_init();
-#ifdef HAVE_ZEROSKIP
-    config_conversations_db = "zeroskip";
-#else
     config_conversations_db = "twoskip";
-#endif
 
     return 0;
 }

cunit/libconfig.testc

@@ -957,7 +957,7 @@ static void test_deprecated_string(void)
 static void test_deprecated_stringlist(void)
 {
     /* { "tlscache_db", "twoskip",
-     *   STRINGLIST("skiplist", "sql", "twoskip", "zeroskip"),
+     *   STRINGLIST("skiplist", "sql", "twoskip"),
      *   "2.5.0", "tls_sessions_db" }
      */
     const char *val;
@@ -994,20 +994,6 @@ static void test_deprecated_stringlist(void)
     val = config_getstring(IMAPOPT_TLS_SESSIONS_DB);
     CU_ASSERT_PTR_NOT_NULL(val);
     CU_ASSERT_STRING_EQUAL(val, "sql");
-
-    /* set both names to different values */
-    CU_SYSLOG_MATCH("Option '.*' is deprecated");
-    config_read_string(
-        "configdirectory: "DBDIR"/conf\n"
-        "tlscache_db: sql\n"
-        "tls_sessions_db: zeroskip\n"
-    );
-    CU_ASSERT_SYSLOG(/*all*/0, 1);
-
-    /* should read new value at the new name */
-    val = config_getstring(IMAPOPT_TLS_SESSIONS_DB);
-    CU_ASSERT_PTR_NOT_NULL(val);
-    CU_ASSERT_STRING_EQUAL(val, "zeroskip");
 }
 
 static void test_deprecated_duration(void)

docsrc/imap/concepts/deployment/databases.rst

@@ -250,7 +250,7 @@ This is either cyrus.squat in each folder, or if you're using Xapian a single
 <userid>.xapianactive file listing active databases with tier name and number.
 
 cyrus.indexed.db is used by the Xapian search engine.  Its file type
-can be: `twoskip`_ (default), `flat`_, `skiplist`_, or ``zeroskip`` and is
+can be: `twoskip`_ (default), `flat`_, or `skiplist`_ and is
 determined by `search_indexed_db` in :cyrusman:`imapd.conf(5)`.
 
 The xapianactive file contains a space separated list of tiers and databases within

lib/cyrusdb.c

@@ -72,7 +72,6 @@ extern struct cyrusdb_backend cyrusdb_skiplist;
 extern struct cyrusdb_backend cyrusdb_quotalegacy;
 extern struct cyrusdb_backend cyrusdb_sql;
 extern struct cyrusdb_backend cyrusdb_twoskip;
-extern struct cyrusdb_backend cyrusdb_zeroskip;
 
 static struct cyrusdb_backend *_backends[] = {
     &cyrusdb_flat,
@@ -82,9 +81,6 @@ static struct cyrusdb_backend *_backends[] = {
     &cyrusdb_sql,
 #endif
     &cyrusdb_twoskip,
-#if defined HAVE_ZEROSKIP
-    &cyrusdb_zeroskip,
-#endif
     NULL };
 
 #define DEFAULT_BACKEND "twoskip"