encoding/json/jsontext: Decoder.Reset and Encoder.Reset should allow nil

[dsnet]

I'm using jsontext.Encoder and jsontext.Decoder with a sync.Pool. Ideally, I should be able to put the encoder/decoder back into the pool without referencing the memory for the underlying io.Reader and io.Writer. Unfortunately, calling Reset(nil) panics. We should permit nil and just allow subsequent method calls to panic.

[gabyhelp]

Related Issues

• encoding/json/v2: enable allocation-free Encoder and Decoder reuse #74538 (closed)
• encoding/json: don't reset before returning buffer to pool #34195 (closed)
• math/big: nil *Int appears to not roundtrip with MarshalText and UnmarshalText #60489

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[ilindan-dev]

"Hi @dsnet! I completely agree with the rationale - allowing Reset(nil) is crucial for sync.Pool reuse so the GC can properly reclaim the underlying io.Reader/io.Writer. Since I'm already familiar with the jsontext internals, I'll put together a CL to remove these panic checks shortly

[ilindan-dev]

Since I already had the codebase fresh in my mind from the previous patch, I went ahead and put together a quick CL for this. Absolutely no rush on the review, just wanted to put it up while I had the time.

[gopherbot]

Change https://go.dev/cl/795960 mentions this issue: encoding/json/jsontext: allow nil io.Reader and io.Writer in Reset