Close underlying stream after process failure in close (#182)

Author: nhz2

src/stream.jl

@@ -186,11 +186,14 @@ end
 
 function Base.close(stream::TranscodingStream)
     mode = stream.state.mode
-    if mode != :panic
-        changemode!(stream, :close)
-    end
-    if !stream.state.stop_on_end
-        close(stream.stream)
+    try
+        if mode != :panic
+            changemode!(stream, :close)
+        end
+    finally
+        if !stream.state.stop_on_end
+            close(stream.stream)
+        end
     end
     return nothing
 end

test/codecdoubleframe.jl

@@ -26,20 +26,20 @@ function TranscodingStreams.process(
         codec  :: DoubleFrameEncoder,
         input  :: TranscodingStreams.Memory,
         output :: TranscodingStreams.Memory,
-        error  :: TranscodingStreams.Error,
+        error_ref  :: TranscodingStreams.Error,
     )
     if input.size == 0
         codec.got_stop_msg[] = true
     end
 
     if output.size < 2
-        error[] = ErrorException("requires a minimum of 2 bytes of output space")
+        error_ref[] = ErrorException("requires a minimum of 2 bytes of output space")
         return 0, 0, :error
     elseif codec.stopped[]
-        error[] = ErrorException("cannot process after stopped")
+        error_ref[] = ErrorException("cannot process after stopped")
         return 0, 0, :error
     elseif codec.got_stop_msg[] && input.size != 0
-        error[] = ErrorException("cannot accept more input after getting stop message")
+        error_ref[] = ErrorException("cannot accept more input after getting stop message")
         return 0, 0, :error
     elseif !codec.opened[]
         output[1] = UInt8('[')
@@ -95,7 +95,7 @@ function TranscodingStreams.process(
         codec  :: DoubleFrameDecoder,
         input  :: TranscodingStreams.Memory,
         output :: TranscodingStreams.Memory,
-        error  :: TranscodingStreams.Error,
+        error_ref  :: TranscodingStreams.Error,
     )
     Δin::Int = 0
     Δout::Int = 0
@@ -167,7 +167,7 @@ function TranscodingStreams.process(
     catch e
         codec.state[]=7
         e isa ErrorException || rethrow()
-        error[] = e
+        error_ref[] = e
         return Δin, Δout, :error
     end
 end
@@ -243,6 +243,27 @@ DoubleFrameDecoderStream(stream::IO; kwargs...) = TranscodingStream(DoubleFrameD
         @test String(take!(sink)) == "[  ][ aabbcc ][ ddee ]"
     end
 
+    @testset "Issue #160 Safely close stream after failure" begin
+        sink = IOBuffer()
+        stream = TranscodingStream(DoubleFrameDecoder(), sink)
+        write(stream, "abc")
+        @test_throws ErrorException("expected [") close(stream)
+        @test !isopen(stream)
+        @test !isopen(sink)
+
+        @testset "nested decoders" begin
+            sink = IOBuffer()
+            stream = TranscodingStream(DoubleFrameDecoder(), sink)
+            stream2 = TranscodingStream(DoubleFrameDecoder(), stream)
+            write(stream2, "abc")
+            # "expected byte" error with caused by "expected ["
+            @test_throws ErrorException("expected byte") close(stream2)
+            @test !isopen(stream2)
+            @test !isopen(stream)
+            @test !isopen(sink)
+        end
+    end
+
     @testset "stop_on_end=true in nested streams" begin
         s1 = DoubleFrameDecoderStream(DoubleFrameEncoderStream(
             DoubleFrameDecoderStream(