hcl2_upgrade escaped quotes fix (#10794)

* clean up extra quoting that can cause text template failures. when everyone else abandons you, regex will always be there.

* LINTING

command/hcl2_upgrade.go

@@ -8,7 +8,9 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	texttemplate "text/template"
 
@@ -437,7 +439,22 @@ func transposeTemplatingCalls(s []byte) []byte {
 		Parse(string(s))
 
 	if err != nil {
-		return fallbackReturn(err, s)
+		if strings.Contains(err.Error(), "unexpected \"\\\\\" in operand") {
+			// This error occurs if the operand in the text template used
+			// escaped quoting \" instead of bactick quoting `
+			// Create a regex to do a string replace on this block, to fix
+			// quoting.
+			q := fixQuoting(string(s))
+			unquoted := []byte(q)
+			tpl, err = texttemplate.New("hcl2_upgrade").
+				Funcs(funcMap).
+				Parse(string(unquoted))
+			if err != nil {
+				return fallbackReturn(err, unquoted)
+			}
+		} else {
+			return fallbackReturn(err, s)
+		}
 	}
 
 	str := &bytes.Buffer{}
@@ -502,7 +519,22 @@ func variableTransposeTemplatingCalls(s []byte) (isLocal bool, body []byte) {
 		Parse(string(s))
 
 	if err != nil {
-		return isLocal, fallbackReturn(err, s)
+		if strings.Contains(err.Error(), "unexpected \"\\\\\" in operand") {
+			// This error occurs if the operand in the text template used
+			// escaped quoting \" instead of bactick quoting `
+			// Create a regex to do a string replace on this block, to fix
+			// quoting.
+			q := fixQuoting(string(s))
+			unquoted := []byte(q)
+			tpl, err = texttemplate.New("hcl2_upgrade").
+				Funcs(funcMap).
+				Parse(string(unquoted))
+			if err != nil {
+				return isLocal, fallbackReturn(err, unquoted)
+			}
+		} else {
+			return isLocal, fallbackReturn(err, s)
+		}
 	}
 
 	str := &bytes.Buffer{}
@@ -1247,3 +1279,23 @@ var PASSTHROUGHS = map[string]string{"NVME_Present": "{{ .NVME_Present }}",
 	"ProviderVagrantfile":        "{{ .ProviderVagrantfile }}",
 	"Sound_Present":              "{{ .Sound_Present }}",
 }
+
+func fixQuoting(old string) string {
+	// This regex captures golang template functions that use escaped quotes:
+	// {{ env \"myvar\" }}
+	re := regexp.MustCompile(`{{\s*\w*\s*(\\".*\\")\s*}}`)
+
+	body := re.ReplaceAllFunc([]byte(old), func(s []byte) []byte {
+		// Get the capture group
+		group := re.ReplaceAllString(string(s), `$1`)
+
+		unquoted, err := strconv.Unquote(fmt.Sprintf("\"%s\"", group))
+		if err != nil {
+			return s
+		}
+		return []byte(strings.Replace(string(s), group, unquoted, 1))
+
+	})
+
+	return string(body)
+}

command/hcl2_upgrade_test.go

@@ -29,6 +29,7 @@ func Test_hcl2_upgrade(t *testing.T) {
 		{folder: "variables-only", flags: []string{}},
 		{folder: "variables-with-variables", flags: []string{}},
 		{folder: "complete-variables-with-template-engine", flags: []string{}},
+		{folder: "escaping", flags: []string{}},
 	}
 
 	for _, tc := range tc {

command/test-fixtures/hcl2_upgrade/escaping/expected.pkr.hcl

@@ -0,0 +1,31 @@
+
+variable "conf" {
+  type    = string
+  default = "${env("ONE")}-${env("ANOTHER")}-${env("BACKTICKED")}"
+}
+
+variable "manyspaces" {
+  type    = string
+  default = "${env("ASDFASDF")}"
+}
+
+variable "nospaces" {
+  type    = string
+  default = "${env("SOMETHING")}"
+}
+
+locals { timestamp = regex_replace(timestamp(), "[- TZ:]", "") }
+# The "legacy_isotime" function has been provided for backwards compatability, but we recommend switching to the timestamp and formatdate functions.
+
+source "null" "autogenerated_1" {
+  communicator = "none"
+}
+
+build {
+  sources = ["source.null.autogenerated_1"]
+
+  provisioner "shell-local" {
+    inline = ["echo ${var.conf}-${local.timestamp}-${legacy_isotime("01-02-2006")}"]
+  }
+
+}

command/test-fixtures/hcl2_upgrade/escaping/input.json

@@ -0,0 +1,21 @@
+{
+	"variables": {
+		"conf": "{{ env \"ONE\" }}-{{env \"ANOTHER\"}}-{{ env  `BACKTICKED` }}",
+		"nospaces": "{{env \"SOMETHING\"}}",
+		"manyspaces": "{{   env \"ASDFASDF\"}}"
+	},
+	"builders": [
+		{
+			"type": "null",
+			"communicator": "none"
+		}
+	],
+	"provisioners": [
+		{
+			"type": "shell-local",
+			"inline": [
+				"echo {{user \"conf\"}}-{{timestamp}}-{{isotime \"01-02-2006\"}}"
+			]
+		}
+	]
+}