Add file lock to prevent concurrent executions

.gitignore

@@ -1,6 +1,7 @@
 *.log
 .DS_Store
 ._.DS_Store
+.lock
 scoop.sublime-workspace
 test/installer/tmp/*
 test/tmp/*

CHANGELOG.md

@@ -7,6 +7,7 @@
 - **install:** Add separator at the end of notes, highlight suggestions ([#6418](https://github.com/ScoopInstaller/Scoop/issues/6418))
 - **download|scoop-download:** Add GitHub issue prompt when the default downloader fails ([#6539](https://github.com/ScoopInstaller/Scoop/issues/6539))
 - **download|scoop-config:** Allow disabling automatic fallback to the default downloader when Aria2c download fails ([#6538](https://github.com/ScoopInstaller/Scoop/issues/6538))
+- **core:** Add file lock to prevent concurrent executions ([#6557](https://github.com/ScoopInstaller/Scoop/issues/6557))
 
 ### Bug Fixes
 

bin/scoop.ps1

@@ -6,48 +6,74 @@ Set-StrictMode -Off
 . "$PSScriptRoot\..\lib\commands.ps1"
 . "$PSScriptRoot\..\lib\help.ps1"
 
-$subCommand = $Args[0]
+$lock_file_path = "$PSScriptRoot\..\.lock"
+$lock_stream = $null
+$lock_show_waiting_message = $true
 
-# for aliases where there's a local function, re-alias so the function takes precedence
-$aliases = Get-Alias | Where-Object { $_.Options -notmatch 'ReadOnly|AllScope' } | ForEach-Object { $_.Name }
-Get-ChildItem Function: | Where-Object -Property Name -In -Value $aliases | ForEach-Object {
-    Set-Alias -Name $_.Name -Value Local:$($_.Name) -Scope Script
+while (-not $lock_stream) {
+    try {
+        $lock_stream = [System.IO.File]::Open($lock_file_path, [System.IO.FileMode]::Create, [System.IO.FileAccess]::Write)
+    } catch [System.IO.IOException] {
+        # Only deal with ERROR_SHARING_VIOLATION or ERROR_LOCK_VIOLATION.
+        $error_code = $_.Exception.HResult -band 0xFFFF
+        if ($error_code -notin 32, 33) {
+            throw
+        }
+
+        if ($lock_show_waiting_message) {
+            Write-Host 'Waiting for exclusive access...'
+            $lock_show_waiting_message = $false
+        }
+        Start-Sleep -Seconds 1
+    }
 }
 
-switch ($subCommand) {
-    ({ $subCommand -in @($null, '-h', '--help', '/?') }) {
-        exec 'help'
+try {
+    $subCommand = $Args[0]
+
+    # for aliases where there's a local function, re-alias so the function takes precedence
+    $aliases = Get-Alias | Where-Object { $_.Options -notmatch 'ReadOnly|AllScope' } | ForEach-Object { $_.Name }
+    Get-ChildItem Function: | Where-Object -Property Name -In -Value $aliases | ForEach-Object {
+        Set-Alias -Name $_.Name -Value Local:$($_.Name) -Scope Script
     }
-    ({ $subCommand -in @('-v', '--version') }) {
-        Write-Host 'Current Scoop version:'
-        if ((Test-GitAvailable) -and (Test-Path "$PSScriptRoot\..\.git") -and ((get_config SCOOP_BRANCH 'master') -ne 'master')) {
-            Invoke-Git -Path "$PSScriptRoot\.." -ArgumentList @('--no-pager', 'log', 'HEAD', '-1', '--oneline')
-        } else {
-            $version = Select-String -Pattern '^## \[(v[\d.]+)\].*?([\d-]+)$' -Path "$PSScriptRoot\..\CHANGELOG.md"
-            Write-Host $version.Matches.Groups[1].Value -ForegroundColor Cyan -NoNewline
-            Write-Host " - Released at $($version.Matches.Groups[2].Value)"
+
+    switch ($subCommand) {
+        ({ $subCommand -in @($null, '-h', '--help', '/?') }) {
+            exec 'help'
         }
-        Write-Host ''
-
-        Get-LocalBucket | ForEach-Object {
-            $bucketLoc = Find-BucketDirectory $_ -Root
-            if ((Test-GitAvailable) -and (Test-Path "$bucketLoc\.git")) {
-                Write-Host "'$_' bucket:"
-                Invoke-Git -Path $bucketLoc -ArgumentList @('--no-pager', 'log', 'HEAD', '-1', '--oneline')
-                Write-Host ''
+        ({ $subCommand -in @('-v', '--version') }) {
+            Write-Host 'Current Scoop version:'
+            if ((Test-GitAvailable) -and (Test-Path "$PSScriptRoot\..\.git") -and ((get_config SCOOP_BRANCH 'master') -ne 'master')) {
+                Invoke-Git -Path "$PSScriptRoot\.." -ArgumentList @('--no-pager', 'log', 'HEAD', '-1', '--oneline')
+            } else {
+                $version = Select-String -Pattern '^## \[(v[\d.]+)\].*?([\d-]+)$' -Path "$PSScriptRoot\..\CHANGELOG.md"
+                Write-Host $version.Matches.Groups[1].Value -ForegroundColor Cyan -NoNewline
+                Write-Host " - Released at $($version.Matches.Groups[2].Value)"
+            }
+            Write-Host ''
+
+            Get-LocalBucket | ForEach-Object {
+                $bucketLoc = Find-BucketDirectory $_ -Root
+                if ((Test-GitAvailable) -and (Test-Path "$bucketLoc\.git")) {
+                    Write-Host "'$_' bucket:"
+                    Invoke-Git -Path $bucketLoc -ArgumentList @('--no-pager', 'log', 'HEAD', '-1', '--oneline')
+                    Write-Host ''
+                }
             }
         }
-    }
-    ({ $subCommand -in (commands) }) {
-        [string[]]$arguments = $Args | Select-Object -Skip 1
-        if ($null -ne $arguments -and $arguments[0] -in @('-h', '--help', '/?')) {
-            exec 'help' @($subCommand)
-        } else {
-            exec $subCommand $arguments
+        ({ $subCommand -in (commands) }) {
+            [string[]]$arguments = $Args | Select-Object -Skip 1
+            if ($null -ne $arguments -and $arguments[0] -in @('-h', '--help', '/?')) {
+                exec 'help' @($subCommand)
+            } else {
+                exec $subCommand $arguments
+            }
+        }
+        default {
+            warn "scoop: '$subCommand' isn't a scoop command. See 'scoop help'."
+            exit 1
         }
     }
-    default {
-        warn "scoop: '$subCommand' isn't a scoop command. See 'scoop help'."
-        exit 1
-    }
+} finally {
+    $lock_stream.Dispose()
 }