feat(checkver): improve JSONPath extraction support (#4522)

bin/checkver.ps1

@@ -213,7 +213,13 @@ while ($in_progress -gt 0) {
     }
 
     if ($jsonpath) {
-        $ver = json_path $page $jsonpath
+        # Return only a single value if regex is absent
+        $noregex = [String]::IsNullOrEmpty($regex)
+        # If reverse is ON and regex is ON,
+        # Then reverse would have no effect because regex handles reverse
+        # on its own
+        # So in this case we have to disable reverse
+        $ver = json_path $page $jsonpath $null ($reverse -and $noregex) $noregex
         if (!$ver) {
             $ver = json_path_legacy $page $jsonpath
         }

lib/json.ps1

@@ -92,32 +92,34 @@ function ConvertToPrettyJson {
     }
 }
 
-function json_path([String] $json, [String] $jsonpath, [Hashtable] $substitutions) {
+function json_path([String] $json, [String] $jsonpath, [Hashtable] $substitutions, [Boolean] $reverse, [Boolean] $single) {
     Add-Type -Path "$psscriptroot\..\supporting\validator\bin\Newtonsoft.Json.dll"
     if ($null -ne $substitutions) {
         $jsonpath = substitute $jsonpath $substitutions ($jsonpath -like "*=~*")
     }
     try {
-        $obj = [Newtonsoft.Json.Linq.JObject]::Parse($json)
+        $obj = [Newtonsoft.Json.Linq.JValue]::Parse($json)
     } catch [Newtonsoft.Json.JsonReaderException] {
-        try {
-            $obj = [Newtonsoft.Json.Linq.JArray]::Parse($json)
-        } catch [Newtonsoft.Json.JsonReaderException] {
-            return $null
-        }
-    }
-
-    try {
-        try {
-            $result = $obj.SelectToken($jsonpath, $true)
-        } catch [Newtonsoft.Json.JsonException] {
-            return $null
-        }
-        return $result.ToString()
-    } catch [System.Management.Automation.MethodInvocationException] {
-        write-host -f DarkRed $_
         return $null
     }
+    try {
+        $result = $obj.SelectTokens($jsonpath, $true)
+        if ($reverse) {
+            # Return versions in reverse order
+            $result = [System.Linq.Enumerable]::Reverse($result)
+        }
+        if ($single) {
+            # Extract First value
+            $result = [System.Linq.Enumerable]::First($result)
+            # Convert first value to string
+            $result = $result.ToString()
+        } else {
+            $result = "$([String]::Join('\n', $result))"
+        }
+        return $result
+    } catch [Exception] {
+        Write-Host $_ -ForegroundColor DarkRed
+    }
 
     return $null
 }