From 9408469458b5ecb66c41ab1b49d475af1518dbda Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Wed, 17 Feb 2021 22:04:32 -0800
Subject: [PATCH 1/6] Add common tools for spell check

---
 .../templates/steps/check-spelling.yml        | 31 +++++++++++
 eng/common/scripts/Test-Spelling.ps1          | 52 +++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 eng/common/pipelines/templates/steps/check-spelling.yml
 create mode 100644 eng/common/scripts/Test-Spelling.ps1

diff --git a/eng/common/pipelines/templates/steps/check-spelling.yml b/eng/common/pipelines/templates/steps/check-spelling.yml
new file mode 100644
index 0000000000000..9aecaa58e04f6
--- /dev/null
+++ b/eng/common/pipelines/templates/steps/check-spelling.yml
@@ -0,0 +1,31 @@
+# Checks spelling of files that changed between the current state of the repo
+# and some ref (branch, tag, etc.) or commit hash. Only runs on PRs.
+# ContinueOnError - true: Pipeline warns on spelling error 
+#                   false: Pipeline fails on spelling error
+
+parameters:
+  ContinueOnError: true
+
+steps:
+  - ${{ if eq(variables['Build.Reason'], 'PullRequest') }}:
+    # Devops uses a git config that changes ref names. 
+    # For example: refs/heads/master -> refs/remotes/origin/master
+    # Set in: fetch = +refs/heads/*:refs/remotes/origin/*
+    # Rather than try to convert $(System.PullRequest.TargetBranch) this
+    # explicitly fetches the ref with a specific name that will not collide with
+    # the other refs fetched
+    - task: PowerShell@2
+      displayName: Fetch ref for $(System.PullRequest.TargetBranch)
+      inputs:
+        pwsh: true
+        targetType: inline
+        script: git fetch origin $(System.PullRequest.TargetBranch):refs/spellcheck/baseref
+
+    - task: PowerShell@2
+      displayName: Check spelling (cspell)
+      continueOnError: ${{ parameters.ContinueOnError }}
+      inputs: 
+        targetType: filePath
+        filePath: eng/common/scripts/Test-Spelling.ps1
+        arguments: -TargetRef refs/spellcheck/baseref
+        pwsh: true
diff --git a/eng/common/scripts/Test-Spelling.ps1 b/eng/common/scripts/Test-Spelling.ps1
new file mode 100644
index 0000000000000..c9c32aed4c373
--- /dev/null
+++ b/eng/common/scripts/Test-Spelling.ps1
@@ -0,0 +1,52 @@
+[CmdletBinding()]
+Param (
+    [Parameter()]
+    [ValidateNotNullOrEmpty()]
+    [string] $TargetRef = 'master'
+)
+
+. $PSScriptRoot/logging.ps1
+
+
+if ((Get-Command npx | Measure-Object).Count -eq 0) { 
+    Write-Error "Could not locate npx. Install NodeJS (includes npm and npx) https://nodejs.org/en/download/"
+    exit 1
+}
+
+$initialDirectory = Get-Location
+$exitCode = 0
+try { 
+    Set-Location "$PSScriptRoot/../../.."
+
+    # Lists names of files that were in some way changed between the 
+    # current ref and $TargetRef. Excludes files that were deleted to
+    # prevent errors in Resolve-Path
+    Write-Host "git diff --diff-filter=d --name-only $TargetRef"
+    $changedFiles = git diff --diff-filter=d --name-only $TargetRef `
+        | Resolve-Path
+    
+    $changedFilesCount = ($changedFiles | Measure-Object).Count
+    Write-Host "Git Detected $changedFilesCount changed file(s). Files checked by cspell may exclude files according to cspell.json"
+
+    if ($changedFilesCount -eq 0) {
+        Write-Host "No changes detected"
+        # The finally block still runs after calling exit here
+        exit $exitCode
+    }
+
+    $changedFilesString = $changedFiles | Join-String -Separator ' '
+
+    Write-Host "npx cspell --config ./eng/cspell.json $changedFilesString"
+    $spellingErrors = Invoke-Expression "npx cspell --config ./eng/cspell.json $changedFilesString"
+
+    if ($spellingErrors) {
+        $exitCode = 1
+        foreach ($spellingError in $spellingErrors) { 
+            LogWarning $spellingError
+        }    
+    }
+} finally {
+    Set-Location $initialDirectory
+}
+
+exit $exitCode
\ No newline at end of file

From 5a63ecaa054cd1eb5b5cc681479aa4b95c30a25a Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Wed, 17 Feb 2021 23:28:12 -0800
Subject: [PATCH 2/6] Updates from further iteration

---
 .../templates/steps/check-spelling.yml        | 15 +++++--
 eng/common/scripts/Test-Spelling.ps1          | 41 ++++++++++++++++---
 2 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/eng/common/pipelines/templates/steps/check-spelling.yml b/eng/common/pipelines/templates/steps/check-spelling.yml
index 9aecaa58e04f6..5958aa2579bc3 100644
--- a/eng/common/pipelines/templates/steps/check-spelling.yml
+++ b/eng/common/pipelines/templates/steps/check-spelling.yml
@@ -2,24 +2,29 @@
 # and some ref (branch, tag, etc.) or commit hash. Only runs on PRs.
 # ContinueOnError - true: Pipeline warns on spelling error 
 #                   false: Pipeline fails on spelling error
+# TargetRef       - Target ref (e.g. master) to compare to create file change
+#                   list
+# CspellConfigPath - Path to cspell.json config location
 
 parameters:
   ContinueOnError: true
+  TargetRef: $(System.PullRequest.TargetBranch)
+  CspellConfigPath: ./.vscode/cspell.json
 
 steps:
   - ${{ if eq(variables['Build.Reason'], 'PullRequest') }}:
     # Devops uses a git config that changes ref names. 
     # For example: refs/heads/master -> refs/remotes/origin/master
     # Set in: fetch = +refs/heads/*:refs/remotes/origin/*
-    # Rather than try to convert $(System.PullRequest.TargetBranch) this
+    # Rather than try to convert ${{ parameters.TargetRef }} this
     # explicitly fetches the ref with a specific name that will not collide with
     # the other refs fetched
     - task: PowerShell@2
-      displayName: Fetch ref for $(System.PullRequest.TargetBranch)
+      displayName: Fetch ref for ${{ parameters.TargetRef }}
       inputs:
         pwsh: true
         targetType: inline
-        script: git fetch origin $(System.PullRequest.TargetBranch):refs/spellcheck/baseref
+        script: git fetch origin ${{ parameters.TargetRef }}:refs/spellcheck/baseref
 
     - task: PowerShell@2
       displayName: Check spelling (cspell)
@@ -27,5 +32,7 @@ steps:
       inputs: 
         targetType: filePath
         filePath: eng/common/scripts/Test-Spelling.ps1
-        arguments: -TargetRef refs/spellcheck/baseref
+        arguments: >- 
+          -TargetRef refs/spellcheck/baseref
+          -CspellConfigPath ${{ parameters.CspellConfigPath }}
         pwsh: true
diff --git a/eng/common/scripts/Test-Spelling.ps1 b/eng/common/scripts/Test-Spelling.ps1
index c9c32aed4c373..b2f8162746166 100644
--- a/eng/common/scripts/Test-Spelling.ps1
+++ b/eng/common/scripts/Test-Spelling.ps1
@@ -2,14 +2,18 @@
 Param (
     [Parameter()]
     [ValidateNotNullOrEmpty()]
-    [string] $TargetRef = 'master'
+    [string] $TargetRef = 'master', 
+
+    [Parameter()]
+    [ValidateNotNullOrEmpty()]
+    [string] $CspellConfigPath = "./.vscode/cspell.json"
 )
 
 . $PSScriptRoot/logging.ps1
 
 
 if ((Get-Command npx | Measure-Object).Count -eq 0) { 
-    Write-Error "Could not locate npx. Install NodeJS (includes npm and npx) https://nodejs.org/en/download/"
+    LogError "Could not locate npx. Install NodeJS (includes npm and npx) https://nodejs.org/en/download/"
     exit 1
 }
 
@@ -36,8 +40,8 @@ try {
 
     $changedFilesString = $changedFiles | Join-String -Separator ' '
 
-    Write-Host "npx cspell --config ./eng/cspell.json $changedFilesString"
-    $spellingErrors = Invoke-Expression "npx cspell --config ./eng/cspell.json $changedFilesString"
+    Write-Host "npx cspell --config $CspellConfigPath $changedFilesString"
+    $spellingErrors = Invoke-Expression "npx cspell --config $CspellConfigPath $changedFilesString"
 
     if ($spellingErrors) {
         $exitCode = 1
@@ -49,4 +53,31 @@ try {
     Set-Location $initialDirectory
 }
 
-exit $exitCode
\ No newline at end of file
+exit $exitCode
+
+<#
+.SYNOPSIS
+Uses cspell (from NPM) to check spelling of recently changed files
+
+.DESCRIPTION
+This script checks files that have changed relative to a base branch (default 
+`master`) for spelling errors. Dictionaries and spelling configurations reside 
+in a configurable `cspell.json` location.
+
+This script uses `npx` and assumes that NodeJS (and by extension `npm` and `npx`
+) are installed on the machine. If it does not detect `npx` it will warn the 
+user and exit with an error. 
+
+The entire file is scanned, not just changed sections. Spelling errors in parts 
+of the file not touched will still be shown.
+
+Running this on the local machine will trigger tests 
+
+.PARAMETER TargetRef
+Optional git ref to compare changes. Default value is `master`.
+
+.PARAMETER CspellConfigPath
+Optional location to use for cspell.json path. Default value is 
+`./.vscode/cspell.json`
+
+#>

From fcf77e6a105d804a164dba2326c419c15f15718d Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Thu, 18 Feb 2021 09:04:51 -0800
Subject: [PATCH 3/6] Review feedback: Add check for git as well

---
 eng/common/scripts/Test-Spelling.ps1 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/eng/common/scripts/Test-Spelling.ps1 b/eng/common/scripts/Test-Spelling.ps1
index b2f8162746166..2ce21095b51d5 100644
--- a/eng/common/scripts/Test-Spelling.ps1
+++ b/eng/common/scripts/Test-Spelling.ps1
@@ -11,6 +11,10 @@ Param (
 
 . $PSScriptRoot/logging.ps1
 
+if ((Get-Command git | Measure-Object).Count -eq 0) { 
+    LogError "Could not locate git. Install git https://git-scm.com/downloads"
+    exit 1
+}
 
 if ((Get-Command npx | Measure-Object).Count -eq 0) { 
     LogError "Could not locate npx. Install NodeJS (includes npm and npx) https://nodejs.org/en/download/"

From 3adcb6b46abcda60d15e680ba5c7f07f96bd36f1 Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Thu, 18 Feb 2021 23:27:31 -0800
Subject: [PATCH 4/6] Review feedback * Use common approach to resolving base
 branch name * Eliminate default base branch "master" as this will be changed
 later, providing no default and using a mandatory parameter means a dev must
 provide the value * Check for existence of $CspellConfigPath * No need to
 Set-Location if run from the root of the repo (most common scenario) * -join

---
 .../templates/steps/check-spelling.yml        | 17 +----
 eng/common/scripts/Test-Spelling.ps1          | 76 ++++++++++---------
 2 files changed, 42 insertions(+), 51 deletions(-)

diff --git a/eng/common/pipelines/templates/steps/check-spelling.yml b/eng/common/pipelines/templates/steps/check-spelling.yml
index 5958aa2579bc3..7654d5b45ffd8 100644
--- a/eng/common/pipelines/templates/steps/check-spelling.yml
+++ b/eng/common/pipelines/templates/steps/check-spelling.yml
@@ -3,7 +3,7 @@
 # ContinueOnError - true: Pipeline warns on spelling error 
 #                   false: Pipeline fails on spelling error
 # TargetRef       - Target ref (e.g. master) to compare to create file change
-#                   list
+#                   list.
 # CspellConfigPath - Path to cspell.json config location
 
 parameters:
@@ -13,19 +13,6 @@ parameters:
 
 steps:
   - ${{ if eq(variables['Build.Reason'], 'PullRequest') }}:
-    # Devops uses a git config that changes ref names. 
-    # For example: refs/heads/master -> refs/remotes/origin/master
-    # Set in: fetch = +refs/heads/*:refs/remotes/origin/*
-    # Rather than try to convert ${{ parameters.TargetRef }} this
-    # explicitly fetches the ref with a specific name that will not collide with
-    # the other refs fetched
-    - task: PowerShell@2
-      displayName: Fetch ref for ${{ parameters.TargetRef }}
-      inputs:
-        pwsh: true
-        targetType: inline
-        script: git fetch origin ${{ parameters.TargetRef }}:refs/spellcheck/baseref
-
     - task: PowerShell@2
       displayName: Check spelling (cspell)
       continueOnError: ${{ parameters.ContinueOnError }}
@@ -33,6 +20,6 @@ steps:
         targetType: filePath
         filePath: eng/common/scripts/Test-Spelling.ps1
         arguments: >- 
-          -TargetRef refs/spellcheck/baseref
+          -TargetRef "origin/$("${{ parameters.TargetRef }}" -replace "refs/heads/")"
           -CspellConfigPath ${{ parameters.CspellConfigPath }}
         pwsh: true
diff --git a/eng/common/scripts/Test-Spelling.ps1 b/eng/common/scripts/Test-Spelling.ps1
index 2ce21095b51d5..0b3abb0808b36 100644
--- a/eng/common/scripts/Test-Spelling.ps1
+++ b/eng/common/scripts/Test-Spelling.ps1
@@ -1,8 +1,8 @@
 [CmdletBinding()]
 Param (
-    [Parameter()]
+    [Parameter(Mandatory)]
     [ValidateNotNullOrEmpty()]
-    [string] $TargetRef = 'master', 
+    [string] $TargetRef,
 
     [Parameter()]
     [ValidateNotNullOrEmpty()]
@@ -21,40 +21,38 @@ if ((Get-Command npx | Measure-Object).Count -eq 0) {
     exit 1
 }
 
-$initialDirectory = Get-Location
+if (!(Test-Path $CspellConfigPath)) {
+    LogError "Could not locate config file $CspellConfigPath"
+    exit 1
+}
+
 $exitCode = 0
-try { 
-    Set-Location "$PSScriptRoot/../../.."
-
-    # Lists names of files that were in some way changed between the 
-    # current ref and $TargetRef. Excludes files that were deleted to
-    # prevent errors in Resolve-Path
-    Write-Host "git diff --diff-filter=d --name-only $TargetRef"
-    $changedFiles = git diff --diff-filter=d --name-only $TargetRef `
-        | Resolve-Path
-    
-    $changedFilesCount = ($changedFiles | Measure-Object).Count
-    Write-Host "Git Detected $changedFilesCount changed file(s). Files checked by cspell may exclude files according to cspell.json"
-
-    if ($changedFilesCount -eq 0) {
-        Write-Host "No changes detected"
-        # The finally block still runs after calling exit here
-        exit $exitCode
-    }
-
-    $changedFilesString = $changedFiles | Join-String -Separator ' '
-
-    Write-Host "npx cspell --config $CspellConfigPath $changedFilesString"
-    $spellingErrors = Invoke-Expression "npx cspell --config $CspellConfigPath $changedFilesString"
-
-    if ($spellingErrors) {
-        $exitCode = 1
-        foreach ($spellingError in $spellingErrors) { 
-            LogWarning $spellingError
-        }    
-    }
-} finally {
-    Set-Location $initialDirectory
+
+# Lists names of files that were in some way changed between the 
+# current ref and $TargetRef. Excludes files that were deleted to
+# prevent errors in Resolve-Path
+Write-Host "git diff --diff-filter=d --name-only $TargetRef"
+$changedFiles = git diff --diff-filter=d --name-only $TargetRef `
+    | Resolve-Path
+
+$changedFilesCount = ($changedFiles | Measure-Object).Count
+Write-Host "Git Detected $changedFilesCount changed file(s). Files checked by cspell may exclude files according to cspell.json"
+
+if ($changedFilesCount -eq 0) {
+    Write-Host "No changes detected"
+    exit $exitCode
+}
+
+$changedFilesString = $changedFiles -join ' '
+
+Write-Host "npx cspell --config $CspellConfigPath $changedFilesString"
+$spellingErrors = Invoke-Expression "npx cspell --config $CspellConfigPath $changedFilesString"
+
+if ($spellingErrors) {
+    $exitCode = 1
+    foreach ($spellingError in $spellingErrors) { 
+        LogWarning $spellingError
+    }    
 }
 
 exit $exitCode
@@ -78,10 +76,16 @@ of the file not touched will still be shown.
 Running this on the local machine will trigger tests 
 
 .PARAMETER TargetRef
-Optional git ref to compare changes. Default value is `master`.
+Git ref to compare changes.
 
 .PARAMETER CspellConfigPath
 Optional location to use for cspell.json path. Default value is 
 `./.vscode/cspell.json`
 
+.EXAMPLE
+./eng/common/scripts/Test-Spelling.ps1 -TargetRef 'target_branch_name'
+
+This will run spell check with changes in the current branch with respect to 
+`target_branch_name`
+
 #>

From 9ea39cea81c35fd69880da7583971f91f50735e2 Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Fri, 19 Feb 2021 15:19:09 -0800
Subject: [PATCH 5/6] Review feedback: Rename TargetRef -> TargetBranch, add
 SourceBranch, Add reference to spelling docs, exit 0, Rename to
 check-spelling-in-changed-files.ps1,

---
 .../templates/steps/check-spelling.yml        | 18 +++++----
 ...s1 => check-spelling-in-changed-files.ps1} | 38 +++++++++++--------
 2 files changed, 33 insertions(+), 23 deletions(-)
 rename eng/common/scripts/{Test-Spelling.ps1 => check-spelling-in-changed-files.ps1} (67%)

diff --git a/eng/common/pipelines/templates/steps/check-spelling.yml b/eng/common/pipelines/templates/steps/check-spelling.yml
index 7654d5b45ffd8..3865a3f26ece8 100644
--- a/eng/common/pipelines/templates/steps/check-spelling.yml
+++ b/eng/common/pipelines/templates/steps/check-spelling.yml
@@ -1,14 +1,15 @@
 # Checks spelling of files that changed between the current state of the repo
 # and some ref (branch, tag, etc.) or commit hash. Only runs on PRs.
-# ContinueOnError - true: Pipeline warns on spelling error 
-#                   false: Pipeline fails on spelling error
-# TargetRef       - Target ref (e.g. master) to compare to create file change
-#                   list.
-# CspellConfigPath - Path to cspell.json config location
+# ContinueOnError   - true: Pipeline warns on spelling error 
+#                     false: Pipeline fails on spelling error
+# TargetBranch      - Target ref (e.g. master) to compare to create file change
+#                     list.
+# CspellConfigPath  - Path to cspell.json config location
 
 parameters:
   ContinueOnError: true
-  TargetRef: $(System.PullRequest.TargetBranch)
+  TargetBranch: $(System.PullRequest.TargetBranch)
+  SourceBranch: HEAD
   CspellConfigPath: ./.vscode/cspell.json
 
 steps:
@@ -18,8 +19,9 @@ steps:
       continueOnError: ${{ parameters.ContinueOnError }}
       inputs: 
         targetType: filePath
-        filePath: eng/common/scripts/Test-Spelling.ps1
+        filePath: eng/common/scripts/check-spelling-in-changed-files.ps1
         arguments: >- 
-          -TargetRef "origin/$("${{ parameters.TargetRef }}" -replace "refs/heads/")"
+          -TargetBranch "origin/$("${{ parameters.TargetBranch }}" -replace "refs/heads/")"
+          -SourceBranch ${{ parameters.SourceBranch }}
           -CspellConfigPath ${{ parameters.CspellConfigPath }}
         pwsh: true
diff --git a/eng/common/scripts/Test-Spelling.ps1 b/eng/common/scripts/check-spelling-in-changed-files.ps1
similarity index 67%
rename from eng/common/scripts/Test-Spelling.ps1
rename to eng/common/scripts/check-spelling-in-changed-files.ps1
index 0b3abb0808b36..cc1b21bf1db0e 100644
--- a/eng/common/scripts/Test-Spelling.ps1
+++ b/eng/common/scripts/check-spelling-in-changed-files.ps1
@@ -1,14 +1,17 @@
 [CmdletBinding()]
 Param (
-    [Parameter(Mandatory)]
-    [ValidateNotNullOrEmpty()]
-    [string] $TargetRef,
+    [Parameter()]
+    [string] $TargetBranch,
+
+    [Parameter()]
+    [string] $SourceBranch,
 
     [Parameter()]
     [ValidateNotNullOrEmpty()]
     [string] $CspellConfigPath = "./.vscode/cspell.json"
 )
 
+$ErrorActionPreference = "Continue"
 . $PSScriptRoot/logging.ps1
 
 if ((Get-Command git | Measure-Object).Count -eq 0) { 
@@ -26,13 +29,11 @@ if (!(Test-Path $CspellConfigPath)) {
     exit 1
 }
 
-$exitCode = 0
-
 # Lists names of files that were in some way changed between the 
-# current ref and $TargetRef. Excludes files that were deleted to
+# current ref and $TargetBranch. Excludes files that were deleted to
 # prevent errors in Resolve-Path
-Write-Host "git diff --diff-filter=d --name-only $TargetRef"
-$changedFiles = git diff --diff-filter=d --name-only $TargetRef `
+Write-Host "git diff --diff-filter=d --name-only $TargetBranch $SourceBranch"
+$changedFiles = git diff --diff-filter=d --name-only $TargetBranch $SourceBranch `
     | Resolve-Path
 
 $changedFilesCount = ($changedFiles | Measure-Object).Count
@@ -40,7 +41,7 @@ Write-Host "Git Detected $changedFilesCount changed file(s). Files checked by cs
 
 if ($changedFilesCount -eq 0) {
     Write-Host "No changes detected"
-    exit $exitCode
+    exit 0
 }
 
 $changedFilesString = $changedFiles -join ' '
@@ -49,13 +50,13 @@ Write-Host "npx cspell --config $CspellConfigPath $changedFilesString"
 $spellingErrors = Invoke-Expression "npx cspell --config $CspellConfigPath $changedFilesString"
 
 if ($spellingErrors) {
-    $exitCode = 1
     foreach ($spellingError in $spellingErrors) { 
         LogWarning $spellingError
-    }    
+    }
+    LogWarning "Spelling errors detected. To correct false positives or learn about spell checking see: https://aka.ms/azsdk/engsys/spellcheck"
 }
 
-exit $exitCode
+exit 0
 
 <#
 .SYNOPSIS
@@ -75,15 +76,22 @@ of the file not touched will still be shown.
 
 Running this on the local machine will trigger tests 
 
-.PARAMETER TargetRef
-Git ref to compare changes.
+.PARAMETER TargetBranch
+Git ref to compare changes. This is usually the "base" (GitHub) or "target" 
+(DevOps) branch for which a pull request would be opened.
+
+.PARAMETER SouceBranch
+Git ref to use instead of changes in current repo state. Use `HEAD` here to 
+check spelling of files that have been committed and exlcude any new files or
+modified files that are not committed. This is most useful in CI scenarios where
+builds may have modified the state of the repo.
 
 .PARAMETER CspellConfigPath
 Optional location to use for cspell.json path. Default value is 
 `./.vscode/cspell.json`
 
 .EXAMPLE
-./eng/common/scripts/Test-Spelling.ps1 -TargetRef 'target_branch_name'
+./eng/common/scripts/Test-Spelling.ps1 -TargetBranch 'target_branch_name'
 
 This will run spell check with changes in the current branch with respect to 
 `target_branch_name`

From cfad164ee53aebe82c1b1e92405b1da5d327d0b3 Mon Sep 17 00:00:00 2001
From: Daniel Jurek <djurek@microsoft.com>
Date: Mon, 22 Feb 2021 13:31:33 -0800
Subject: [PATCH 6/6] Review feedback: Remove ValidateNotNullOrEmpty (we do
 more definitive validation farther down that will also catch these errors),
 Update comments and script name

---
 eng/common/scripts/check-spelling-in-changed-files.ps1 | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/eng/common/scripts/check-spelling-in-changed-files.ps1 b/eng/common/scripts/check-spelling-in-changed-files.ps1
index cc1b21bf1db0e..8a9654d203c76 100644
--- a/eng/common/scripts/check-spelling-in-changed-files.ps1
+++ b/eng/common/scripts/check-spelling-in-changed-files.ps1
@@ -7,7 +7,6 @@ Param (
     [string] $SourceBranch,
 
     [Parameter()]
-    [ValidateNotNullOrEmpty()]
     [string] $CspellConfigPath = "./.vscode/cspell.json"
 )
 
@@ -30,7 +29,7 @@ if (!(Test-Path $CspellConfigPath)) {
 }
 
 # Lists names of files that were in some way changed between the 
-# current ref and $TargetBranch. Excludes files that were deleted to
+# current $SourceBranch and $TargetBranch. Excludes files that were deleted to
 # prevent errors in Resolve-Path
 Write-Host "git diff --diff-filter=d --name-only $TargetBranch $SourceBranch"
 $changedFiles = git diff --diff-filter=d --name-only $TargetBranch $SourceBranch `
@@ -84,14 +83,15 @@ Git ref to compare changes. This is usually the "base" (GitHub) or "target"
 Git ref to use instead of changes in current repo state. Use `HEAD` here to 
 check spelling of files that have been committed and exlcude any new files or
 modified files that are not committed. This is most useful in CI scenarios where
-builds may have modified the state of the repo.
+builds may have modified the state of the repo. Leaving this parameter blank  
+includes files for whom changes have not been committed. 
 
 .PARAMETER CspellConfigPath
 Optional location to use for cspell.json path. Default value is 
 `./.vscode/cspell.json`
 
 .EXAMPLE
-./eng/common/scripts/Test-Spelling.ps1 -TargetBranch 'target_branch_name'
+./eng/common/scripts/check-spelling-in-changed-files.ps1 -TargetBranch 'target_branch_name'
 
 This will run spell check with changes in the current branch with respect to 
 `target_branch_name`