Merge pull request #492 from adamralph/pathext

Pathext

.cspell.json

@@ -29,6 +29,7 @@
     "NuGet",
     "nupkg",
     "paramref",
+    "PATHEXT",
     "pipefail",
     "refs",
     "Robocopy",

SimpleExec/Command.cs

@@ -16,9 +16,6 @@ namespace SimpleExec
     /// </summary>
     public static class Command
     {
-        // an experiment in Windows revealed this order of precedence
-        private static readonly List<string> windowsExecutableExtensions = new List<string> { "exe", "bat", "cmd" };
-
         private static readonly Action<IDictionary<string, string?>> defaultAction = _ => { };
         private static readonly string defaultEchoPrefix = Assembly.GetEntryAssembly()?.GetName().Name ?? "SimpleExec";
 
@@ -385,6 +382,15 @@ private static string Resolve(string name)
                 return name;
             }
 
+            var pathExt = Environment.GetEnvironmentVariable("PATHEXT") ?? ".EXE;.BAT;.CMD";
+
+            var windowsExecutableExtensions = pathExt.Split(';')
+                .Select(extension => extension.TrimStart('.'))
+                .Where(extension =>
+                    string.Equals(extension, "exe", StringComparison.OrdinalIgnoreCase) ||
+                    string.Equals(extension, "bat", StringComparison.OrdinalIgnoreCase) ||
+                    string.Equals(extension, "cmd", StringComparison.OrdinalIgnoreCase));
+
             var searchFileNames = string.IsNullOrEmpty(extension)
                 ? windowsExecutableExtensions.Select(ex => Path.ChangeExtension(name, ex)).ToList()
                 : new List<string> { name, };

SimpleExecTests/Infra/WindowsTheoryAttribute.cs

@@ -0,0 +1,14 @@
+using System.Runtime.InteropServices;
+using Xunit;
+
+namespace SimpleExecTests.Infra
+{
+    internal sealed class WindowsTheoryAttribute : TheoryAttribute
+    {
+        public override string Skip
+        {
+            get => !RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "Windows only" : base.Skip;
+            set => base.Skip = value;
+        }
+    }
+}

SimpleExecTests/RunningCommands.cs

@@ -163,5 +163,49 @@ public static async Task RunningCommandsInPathOnWindows()
             // assert
             Assert.Null(exception);
         }
+
+        [WindowsTheory]
+        [InlineData(".BAT;.CMD", "hello from bat")]
+        [InlineData(".CMD;.BAT", "hello from cmd")]
+        public static async Task RunningCommandsInPathOnWindowsWithSpecificPathExt(
+            string pathExt, string expected)
+        {
+            // arrange
+            var directory = Path.Combine(
+                Path.GetTempPath(),
+                "SimpleExecTests",
+                DateTimeOffset.UtcNow.UtcTicks.ToString(CultureInfo.InvariantCulture),
+                "RunningCommandsInPathOnWindows");
+
+            _ = Directory.CreateDirectory(directory);
+
+            if (!SpinWait.SpinUntil(() => Directory.Exists(directory), 50))
+            {
+                throw new IOException($"Failed to create directory '{directory}'.");
+            }
+
+            var name = Path.GetFileNameWithoutExtension(Path.GetRandomFileName());
+            var batName = Path.Combine(directory, Path.ChangeExtension(name, "bat"));
+            await File.WriteAllTextAsync(batName, "@echo hello from bat");
+
+            var cmdName = Path.Combine(directory, Path.ChangeExtension(name, "cmd"));
+            await File.WriteAllTextAsync(cmdName, "@echo hello from cmd");
+
+            Environment.SetEnvironmentVariable(
+                "PATH",
+                $"{Environment.GetEnvironmentVariable("PATH")}{Path.PathSeparator}{directory}",
+                EnvironmentVariableTarget.Process);
+
+            Environment.SetEnvironmentVariable(
+                "PATHEXT",
+                pathExt,
+                EnvironmentVariableTarget.Process);
+
+            // act
+            var actual = (await Command.ReadAsync(name)).StandardOutput.Trim();
+
+            // assert
+            Assert.Equal(expected, actual);
+        }
     }
 }