From 73611fdbd3916808fd82aafeaa1a2e32164c3596 Mon Sep 17 00:00:00 2001
From: Marcel van Lohuizen <mpvl@gmail.com>
Date: Wed, 6 Mar 2024 15:14:14 +0100
Subject: [PATCH] internal/core/adt: guard visual debugger from opening too
 many tabs
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add some guards to avoid opening too many browser tabs when
debugging and switching from TestX to TestEval(Alpha).

We both require an explict flag for opening tabs and have a maximum
count for how many tabs can be opened.

Issue #2884

Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I5aa1bf6726e10d7da4baa73770f6fd1374a0e790
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1191570
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
---
 internal/core/adt/debug.go     | 33 ++++++++++++++++++++++++++-------
 internal/core/adt/eval_test.go |  5 ++---
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/internal/core/adt/debug.go b/internal/core/adt/debug.go
index 4821a184299..c803ac602b9 100644
--- a/internal/core/adt/debug.go
+++ b/internal/core/adt/debug.go
@@ -40,9 +40,34 @@ func RecordDebugGraph(ctx *OpContext, v *Vertex, name string) {
 	}
 }
 
+var (
+	// DebugDeps enables dependency tracking for debugging purposes.
+	// It is off by default, as it adds a significant overhead.
+	//
+	// TODO: hook this init CUE_DEBUG, once we have set this up as a single
+	// environment variable. For instance, CUE_DEBUG=matchdeps=1.
+	DebugDeps = false
+
+	OpenGraphs = false
+
+	// MaxGraphs is the maximum number of debug graphs to be opened. To avoid
+	// confusion, a panic will be raised if this number is exceeded.
+	MaxGraphs = 10
+
+	numberOpened = 0
+)
+
 // OpenNodeGraph takes a given mermaid graph and opens it in the system default
 // browser.
 func OpenNodeGraph(title, path, code, out, graph string) {
+	if !OpenGraphs {
+		return
+	}
+	if numberOpened > MaxGraphs {
+		panic("too many debug graphs opened")
+	}
+	numberOpened++
+
 	err := os.MkdirAll(path, 0755)
 	if err != nil {
 		log.Fatal(err)
@@ -214,13 +239,6 @@ type ccDep struct {
 	taskID int
 }
 
-// DebugDeps enables dependency tracking for debugging purposes.
-// It is off by default, as it adds a significant overhead.
-//
-// TODO: hook this init CUE_DEBUG, once we have set this up as a single
-// environment variable. For instance, CUE_DEBUG=matchdeps=1.
-var DebugDeps = false
-
 func (c *closeContext) addDependent(kind depKind, dependant *closeContext) *ccDep {
 	if !DebugDeps {
 		return nil
@@ -643,6 +661,7 @@ func (m *mermaidContext) pstr(cc *closeContext) string {
 	addFlag(cc.isClosed, 'c')
 	addFlag(cc.isClosedOnce, 'C')
 	addFlag(cc.hasEllipsis, 'o')
+	flags.WriteByte(cc.arcType.String()[0])
 	io.Copy(w, flags)
 
 	w.WriteString(close)
diff --git a/internal/core/adt/eval_test.go b/internal/core/adt/eval_test.go
index e2f36dd5756..688ab21d13e 100644
--- a/internal/core/adt/eval_test.go
+++ b/internal/core/adt/eval_test.go
@@ -201,11 +201,10 @@ func TestX(t *testing.T) {
 	verbosity = 1 // comment to turn logging off.
 
 	adt.DebugDeps = true
+	// adt.OpenGraphs = true
 
 	var version internal.EvaluatorVersion
 	version = internal.DevVersion // comment to use default implementation.
-	openGraph := true
-	openGraph = false
 
 	in := `
 -- cue.mod/module.cue --
@@ -242,7 +241,7 @@ module: "mod.test"
 	adt.Verbosity = 0
 
 	out := debug.NodeString(r, v, nil)
-	if openGraph {
+	if adt.OpenGraphs {
 		for p, g := range ctx.ErrorGraphs {
 			path := filepath.Join(".debug/TestX", p)
 			adt.OpenNodeGraph("TestX", path, in, out, g)