Implement location history feature for Set-Location.
This makes it possible to go back to the last directory using 'cd -', which is exactly the same syntax as on Linux shells.

This makes it possible to go back to the last directory using 'cd -', which is exactly the same syntax as on Linux shells.
Use an existing stack implementation instead of relying on an environ…
…ment variable and move logic for 'cd -' into the internal class of SessionState.Path.SetLocation Keep the (additional) setting of an environment for Unix system in case of mixed usage of cd and Set-Location to provide consistency.
PowerShell · iSazonov · Jun 26, 2018 · iSazonov · Jun 26, 2018 · bergmeister
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
@@ -1054,6 +1071,29 @@ protected override void ProcessRecord()
            }
        } // ProcessRecord

+        private string ReplacePathWithLastLocationIfApplicable(string path)
+        {
+            Environment.SetEnvironmentVariable("DEBUG_PATH", Path);
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
                        result = SessionState.Path.SetLocation(Path, CmdletProviderContext);
+                        Environment.SetEnvironmentVariable(environmentVariableNameForPreviousLocation, initialPath);
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
                        result = SessionState.Path.SetDefaultLocationStack(StackName);
+                        Environment.SetEnvironmentVariable(environmentVariableNameForPreviousLocation, initialPath);
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
-                    {
+                    {   
+                        relationshipPath = ReplacePathWithLastLocationIfApplicable(relationshipPath);
+                        var initialPath = SessionState.Path.CurrentLocation.Path;
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
-                        result = SessionState.Path.SetLocation (relationshipPath, CmdletProviderContext);
+                        relationshipPath = ReplacePathWithLastLocationIfApplicable(relationshipPath);
+                        var initialPath = SessionState.Path.CurrentLocation;
+                        result = SessionState.Path.SetLocation(relationshipPath, CmdletProviderContext);
diff --git a/src/System.Management.Automation/resources/LocationStrings.resx b/src/System.Management.Automation/resources/LocationStrings.resx
@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="utf-8"?>
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
+            It 'Should go to last location when specifying minus as a path using alias' {
+                $initialLocation = Get-Location
+                Set-Location ([System.IO.Path]::GetTempPath())
+                cd -
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Navigation.cs
@@ -916,6 +916,10 @@ protected override void ProcessRecord()
                        }

                        result = SessionState.Path.SetLocation(Path, CmdletProviderContext);
+#if UNIX
+                        // Be consistent with most Unix shells that set the environment variable 'OLDPWD' when changing location
+                        Environment.SetEnvironmentVariable("OLDPWD", Path);
diff --git a/src/System.Management.Automation/engine/SessionStateLocationAPIs.cs b/src/System.Management.Automation/engine/SessionStateLocationAPIs.cs
+            {
+                return PopLocation(locationStackHistoryId);
+            }
+            PushCurrentLocation(locationStackHistoryId);
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
+                $tempLocation = Get-Location
+                Set-Location -
+                Set-Location -
+                (Get-Location).Path | Should Be ($tempLocation).Path
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
+                (Get-Location).Path | Should Be ($tempLocation).Path
+            }
+
+            It 'Should fail if there is no last location' {
diff --git a/src/System.Management.Automation/engine/SessionStateLocationAPIs.cs b/src/System.Management.Automation/engine/SessionStateLocationAPIs.cs
+            bool pushNextLocation = true;
+            if (originalPath.Equals("-", StringComparison.OrdinalIgnoreCase))
+            {
+                if (_workingLocationHistoryStack.Count > 0)
diff --git a/src/System.Management.Automation/engine/Utils.cs b/src/System.Management.Automation/engine/Utils.cs
+        {
+            this.AddFirst(item);
+
+            if(this.Count > _capacity)
diff --git a/src/System.Management.Automation/engine/SessionState.cs b/src/System.Management.Automation/engine/SessionState.cs
@@ -65,6 +66,9 @@ internal SessionStateInternal(SessionStateInternal parent, bool linkToGlobal, Ex
            // is used for the pushd and popd commands

            _workingLocationStack = new Dictionary<String, Stack<PathInfo>>(StringComparer.OrdinalIgnoreCase);
+            // conservative choice to limit the memory impact in case of a regression
+            const int locationHistoryLimit = 20;
+            _workingLocationHistoryStack = new BoundedStack<PathInfo>(locationHistoryLimit);
diff --git a/src/System.Management.Automation/engine/SessionState.cs b/src/System.Management.Automation/engine/SessionState.cs
@@ -65,6 +66,9 @@ internal SessionStateInternal(SessionStateInternal parent, bool linkToGlobal, Ex
            // is used for the pushd and popd commands

            _workingLocationStack = new Dictionary<String, Stack<PathInfo>>(StringComparer.OrdinalIgnoreCase);
+            // conservative choice to limit the memory impact in case of a regression
diff --git a/src/System.Management.Automation/engine/Utils.cs b/src/System.Management.Automation/engine/Utils.cs
+        internal T Pop()
+        {
+            var item = this.First.Value;
+            this.RemoveFirst();