From 61eab4db0550b6c02988cdb2a3714049396cbf31 Mon Sep 17 00:00:00 2001
From: Steven Masley <stevenmasley@coder.com>
Date: Wed, 21 Sep 2022 08:08:11 -0400
Subject: [PATCH 1/2] chore: Add linter rule to prevent breaking of sse

---
 scripts/rules.go | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/scripts/rules.go b/scripts/rules.go
index c34ae6ed3bff3..1c0385a655eaa 100644
--- a/scripts/rules.go
+++ b/scripts/rules.go
@@ -8,16 +8,20 @@
 // - https://pkg.go.dev/github.com/quasilyte/go-ruleguard/dsl
 //
 // You run one of the following commands to execute your go rules only:
-//   golangci-lint run
-//   golangci-lint run --disable-all --enable=gocritic
+//
+//	golangci-lint run
+//	golangci-lint run --disable-all --enable=gocritic
+//
 // Note: don't forget to run `golangci-lint cache clean`!
 package gorules
 
 import (
 	"github.com/quasilyte/go-ruleguard/dsl"
+	"github.com/quasilyte/go-ruleguard/dsl/types"
 )
 
 // Use xerrors everywhere! It provides additional stacktrace info!
+//
 //nolint:unused,deadcode,varnamelen
 func xerrors(m dsl.Matcher) {
 	m.Import("errors")
@@ -35,6 +39,7 @@ func xerrors(m dsl.Matcher) {
 }
 
 // databaseImport enforces not importing any database types into /codersdk.
+//
 //nolint:unused,deadcode,varnamelen
 func databaseImport(m dsl.Matcher) {
 	m.Import("github.com/coder/coder/coderd/database")
@@ -46,6 +51,7 @@ func databaseImport(m dsl.Matcher) {
 // doNotCallTFailNowInsideGoroutine enforces not calling t.FailNow or
 // functions that may themselves call t.FailNow in goroutines outside
 // the main test goroutine. See testing.go:834 for why.
+//
 //nolint:unused,deadcode,varnamelen
 func doNotCallTFailNowInsideGoroutine(m dsl.Matcher) {
 	m.Import("testing")
@@ -84,6 +90,7 @@ func doNotCallTFailNowInsideGoroutine(m dsl.Matcher) {
 // useStandardTimeoutsAndDelaysInTests ensures all tests use common
 // constants for timeouts and delays in usual scenarios, this allows us
 // to tweak them based on platform (important to avoid CI flakes).
+//
 //nolint:unused,deadcode,varnamelen
 func useStandardTimeoutsAndDelaysInTests(m dsl.Matcher) {
 	m.Import("github.com/stretchr/testify/require")
@@ -232,3 +239,30 @@ func ProperRBACReturn(m dsl.Matcher) {
 	}
 	`).Report("Must write to 'ResponseWriter' before returning'")
 }
+
+// FullResponseWriter ensures that any overridden response writer has full
+// functionality. Mainly is hijackable and flushable.
+func FullResponseWriter(m dsl.Matcher) {
+	m.Match(`
+	type $w struct {
+		$*_
+		http.ResponseWriter
+		$*_
+	}
+	`).
+		At(m["w"]).
+		Where(m["w"].Filter(notImplementsFullResponseWriter)).
+		Report("ResponseWriter \"$w\" must implement http.Flusher and http.Hijacker")
+}
+
+// notImplementsFullResponseWriter returns false if the type does not implement
+// http.Flusher, http.Hijacker, and http.ResponseWriter.
+func notImplementsFullResponseWriter(ctx *dsl.VarFilterContext) bool {
+	flusher := ctx.GetInterface(`net/http.Flusher`)
+	hijacker := ctx.GetInterface(`net/http.Hijacker`)
+	writer := ctx.GetInterface(`net/http.ResponseWriter`)
+	p := types.NewPointer(ctx.Type)
+	return !(types.Implements(types.NewPointer(ctx.Type), writer) || types.Implements(ctx.Type, writer)) ||
+		!(types.Implements(types.NewPointer(ctx.Type), flusher) || types.Implements(ctx.Type, flusher)) ||
+		!(types.Implements(p, hijacker) || types.Implements(ctx.Type, hijacker))
+}

From e6025e30a067ae36108c42f8357146a154ed6c01 Mon Sep 17 00:00:00 2001
From: Steven Masley <stevenmasley@coder.com>
Date: Wed, 21 Sep 2022 08:12:22 -0400
Subject: [PATCH 2/2] Simplify slightly, reuse pointer

---
 scripts/rules.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/rules.go b/scripts/rules.go
index 1c0385a655eaa..38abb44e8107a 100644
--- a/scripts/rules.go
+++ b/scripts/rules.go
@@ -262,7 +262,7 @@ func notImplementsFullResponseWriter(ctx *dsl.VarFilterContext) bool {
 	hijacker := ctx.GetInterface(`net/http.Hijacker`)
 	writer := ctx.GetInterface(`net/http.ResponseWriter`)
 	p := types.NewPointer(ctx.Type)
-	return !(types.Implements(types.NewPointer(ctx.Type), writer) || types.Implements(ctx.Type, writer)) ||
-		!(types.Implements(types.NewPointer(ctx.Type), flusher) || types.Implements(ctx.Type, flusher)) ||
+	return !(types.Implements(p, writer) || types.Implements(ctx.Type, writer)) ||
+		!(types.Implements(p, flusher) || types.Implements(ctx.Type, flusher)) ||
 		!(types.Implements(p, hijacker) || types.Implements(ctx.Type, hijacker))
 }