1 files changed, 54 insertions, 0 deletions
diff --git a/tests/stdlib/tmarshalsegfault.nim b/tests/stdlib/tmarshalsegfault.nim
new file mode 100644
index 000000000..71f2766c8
--- /dev/null
+++ b/tests/stdlib/tmarshalsegfault.nim
@@ -0,0 +1,54 @@
+# issue #12405
+
+import std/[marshal, streams, times, tables, os, assertions]
+
+type AiredEpisodeState * = ref object
+    airedAt * : DateTime
+    tvShowId * : string
+    seasonNumber * : int
+    number * : int
+    title * : string
+
+type ShowsWatchlistState * = ref object
+    aired * : seq[AiredEpisodeState]
+
+type UiState * = ref object
+    shows: ShowsWatchlistState
+
+# Helpers to marshal and unmarshal
+proc load * ( state : var UiState, file : string ) =
+    var strm = newFileStream( file, fmRead )
+
+    strm.load( state )
+
+    strm.close()
+
+proc store * ( state : UiState, file : string ) =
+    var strm = newFileStream( file, fmWrite )
+
+    strm.store( state )
+
+    strm.close()
+
+# 1. We fill the state initially
+var state : UiState = UiState( shows: ShowsWatchlistState( aired: @[] ) )
+
+# VERY IMPORTANT: For some reason, small numbers (like 2 or 3) don't trigger the bug. Anything above 7 or 8 on my machine triggers though
+for i in 0..30:
+    var episode = AiredEpisodeState( airedAt: now(), tvShowId: "1", seasonNumber: 1, number: 1, title: "string" )
+
+    state.shows.aired.add( episode )
+
+# 2. Store it in a file with the marshal module, and then load it back up
+store( state, "tmarshalsegfault_data" )
+load( state, "tmarshalsegfault_data" )
+removeFile("tmarshalsegfault_data")
+
+# 3. VERY IMPORTANT: Without this line, for some reason, everything works fine
+state.shows.aired[ 0 ] = AiredEpisodeState( airedAt: now(), tvShowId: "1", seasonNumber: 1, number: 1, title: "string" )
+
+# 4. And formatting the airedAt date will now trigger the exception
+for ep in state.shows.aired:
+    let x = $ep.seasonNumber & "x" & $ep.number & " (" & $ep.airedAt & ")"
+    let y = $ep.seasonNumber & "x" & $ep.number & " (" & $ep.airedAt & ")"
+    doAssert x == y