test thread breakage when messages are removed and re-added

[notmuch] / test / T590-thread-breakage.sh

diff --git a/test/T590-thread-breakage.sh b/test/T590-thread-breakage.sh
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+#!/usr/bin/env bash
+#
+# Copyright (c) 2016 Daniel Kahn Gillmor
+#
+
+test_description='thread breakage during reindexing
+
+notmuch uses ghost documents to track messages we have seen references
+to but have never seen.  Regardless of the order of delivery, message
+deletion, and reindexing, the list of ghost messages for a given
+stored corpus should not vary, so that threads can be reassmebled
+cleanly.
+
+In practice, we accept a small amount of variation (and therefore
+traffic pattern metadata leakage to be stored in the index) for the
+sake of efficiency.
+
+This test also embeds some subtests to ensure that indexing actually
+works properly and attempted fixes to threading issues do not break
+the expected contents of the index.'
+
+. ./test-lib.sh || exit 1
+
+message_a() {
+    mkdir -p ${MAIL_DIR}/cur
+    cat > ${MAIL_DIR}/cur/a <<EOF
+Subject: First message
+Message-ID: <a@example.net>
+From: Alice <alice@example.net>
+To: Bob <bob@example.net>
+Date: Thu, 31 Mar 2016 20:10:00 -0400
+
+This is the first message in the thread.
+Apple
+EOF
+}
+
+message_b() {
+    mkdir -p ${MAIL_DIR}/cur
+    cat > ${MAIL_DIR}/cur/b <<EOF
+Subject: Second message
+Message-ID: <b@example.net>
+In-Reply-To: <a@example.net>
+References: <a@example.net>
+From: Bob <bob@example.net>
+To: Alice <alice@example.net>
+Date: Thu, 31 Mar 2016 20:15:00 -0400
+
+This is the second message in the thread.
+Banana
+EOF
+}
+
+
+test_content_count() {
+    test_begin_subtest "${3:-looking for $2 instance of '$1'}"
+    count=$(notmuch count --output=threads "$1")
+    test_expect_equal "$count" "$2"
+}
+
+test_thread_count() {
+    test_begin_subtest "${2:-Expecting $1 thread(s)}"
+    count=$(notmuch count --output=threads)
+    test_expect_equal "$count" "$1"
+}
+
+test_ghost_count() {
+    test_begin_subtest "${2:-Expecting $1 ghosts(s)}"
+    ghosts=$(../ghost-report ${MAIL_DIR}/.notmuch/xapian)
+    test_expect_equal "$ghosts" "$1"
+}
+
+notmuch new >/dev/null
+
+test_thread_count 0 'There should be no threads initially'
+test_ghost_count 0 'There should be no ghosts initially'
+
+message_a
+notmuch new >/dev/null
+test_thread_count 1 'One message in: one thread'
+test_content_count apple 1
+test_content_count banana 0
+test_ghost_count 0
+
+message_b
+notmuch new >/dev/null
+test_thread_count 1 'Second message in the same thread: one thread'
+test_content_count apple 1
+test_content_count banana 1
+test_ghost_count 0
+
+rm -f ${MAIL_DIR}/cur/a
+notmuch new >/dev/null
+test_thread_count 1 'First message removed: still only one thread'
+test_content_count apple 0
+test_content_count banana 1
+test_begin_subtest 'should be one ghost after first message removed'
+test_subtest_known_broken
+ghosts=$(../ghost-report ${MAIL_DIR}/.notmuch/xapian)
+test_expect_equal "$ghosts" "1"
+
+message_a
+notmuch new >/dev/null
+# this is known to fail (it shows 2 threads) because no "ghost
+# message" was created for message A when it was removed from the
+# index, despite message B still pointing to it.
+test_begin_subtest 'First message reappears: should return to the same thread'
+test_subtest_known_broken
+count=$(notmuch count --output=threads)
+test_expect_equal "$count" "1"
+test_content_count apple 1
+test_content_count banana 1
+test_ghost_count 0
+
+rm -f ${MAIL_DIR}/cur/b
+notmuch new >/dev/null
+test_thread_count 1 'Removing second message: still only one thread'
+test_content_count apple 1
+test_content_count banana 0
+test_ghost_count 0 'No ghosts should remain after deletion of second message'
+
+rm -f ${MAIL_DIR}/cur/a
+notmuch new >/dev/null
+test_thread_count 0 'All messages gone: no threads'
+test_content_count apple 0
+test_content_count banana 0
+test_ghost_count 0
+
+test_done