From 69aa78ab169e8fa5d96561462b0a07aa5030bad6 Mon Sep 17 00:00:00 2001 From: Tyler Christensen Date: Sat, 30 Apr 2022 16:06:10 -0600 Subject: [PATCH] plumbing: packp, Avoid duplicate encoding when overriding a Capability value. (#521) Previously, calling `Set($CAPABILITY, ...)` on a `capability.List` where `$CAPABILITY` was already present would correctly replace the existing value of that capability, but would also result in that capability being listed twice in the internal `l.sort` slice. This manifested publicly when the `List` was encoded as the same capability appearing twice with the same value in the encoded output. --- plumbing/protocol/packp/capability/list.go | 4 +++- plumbing/protocol/packp/capability/list_test.go | 11 +++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/plumbing/protocol/packp/capability/list.go b/plumbing/protocol/packp/capability/list.go index f41ec799c..553d81cbe 100644 --- a/plumbing/protocol/packp/capability/list.go +++ b/plumbing/protocol/packp/capability/list.go @@ -86,7 +86,9 @@ func (l *List) Get(capability Capability) []string { // Set sets a capability removing the previous values func (l *List) Set(capability Capability, values ...string) error { - delete(l.m, capability) + if _, ok := l.m[capability]; ok { + l.m[capability].Values = l.m[capability].Values[:0] + } return l.Add(capability, values...) } diff --git a/plumbing/protocol/packp/capability/list_test.go b/plumbing/protocol/packp/capability/list_test.go index 61b0b13be..71181cbc9 100644 --- a/plumbing/protocol/packp/capability/list_test.go +++ b/plumbing/protocol/packp/capability/list_test.go @@ -122,6 +122,17 @@ func (s *SuiteCapabilities) TestSetEmpty(c *check.C) { c.Assert(cap.Get(Agent), check.HasLen, 1) } +func (s *SuiteCapabilities) TestSetDuplicate(c *check.C) { + cap := NewList() + err := cap.Set(Agent, "baz") + c.Assert(err, check.IsNil) + + err = cap.Set(Agent, "bar") + c.Assert(err, check.IsNil) + + c.Assert(cap.String(), check.Equals, "agent=bar") +} + func (s *SuiteCapabilities) TestGetEmpty(c *check.C) { cap := NewList() c.Assert(cap.Get(Agent), check.HasLen, 0)