feat(dsc): add skipExistingInit

resolves #7560

Co-authored-by: JanDeDobbeleer <2492783+JanDeDobbeleer@users.noreply.github.com>

Author: Copilot

src/shell/dsc.go

@@ -28,8 +28,9 @@ func DSC() *dsc.Resource[*Shell] {
 }
 
 type Shell struct {
-	Command string `json:"command,omitempty" jsonschema:"title=Command,description=The oh-my-posh init command to run"`
-	Name    string `json:"name,omitempty" jsonschema:"title=Shell name,description=The name of the shell"`
+	Command          string `json:"command,omitempty" jsonschema:"title=Command,description=The oh-my-posh init command to run"`
+	Name             string `json:"name,omitempty" jsonschema:"title=Shell name,description=The name of the shell"`
+	SkipExistingInit bool   `json:"skipExistingInit,omitempty" jsonschema:"title=Skip existing init,description=Treat any existing oh-my-posh init line as compliant instead of rewriting it"` //nolint:lll
 }
 
 func (s *Shell) Equal(shell *Shell) bool {
@@ -149,6 +150,11 @@ func (s *Shell) updateShellConfig(content string) (string, bool) {
 	initLineStr := lines[initLinePos]
 	shellCommand := s.shellCommand()
 
+	if s.SkipExistingInit {
+		log.Debug("existing oh-my-posh init line found, skipping update")
+		return content, false
+	}
+
 	// validate if we have the same command
 	if strings.Contains(initLineStr, shellCommand) {
 		log.Debug("oh-my-posh already correctly configured")

src/shell/dsc_test.go

@@ -265,6 +265,28 @@ func TestUpdateShellConfig(t *testing.T) {
 			expectedOutput: "if command -v oh-my-posh >/dev/null 2>&1; then\n \t  eval \"$(oh-my-posh init bash --config theme.json)\"\nfi\n",
 			expectedUpdate: true,
 		},
+		{
+			name: "preserve existing initialization when configured",
+			shell: &Shell{
+				Name:             "pwsh",
+				Command:          "oh-my-posh init pwsh",
+				SkipExistingInit: true,
+			},
+			content:        "oh-my-posh init pwsh --config \"$HOME/.config/oh-my-posh/custom.omp.json\" | Invoke-Expression\n",
+			expectedOutput: "oh-my-posh init pwsh --config \"$HOME/.config/oh-my-posh/custom.omp.json\" | Invoke-Expression\n",
+			expectedUpdate: false,
+		},
+		{
+			name: "add initialization when skip existing is enabled but no init line exists",
+			shell: &Shell{
+				Name:             "pwsh",
+				Command:          "oh-my-posh init pwsh",
+				SkipExistingInit: true,
+			},
+			content:        "$env:PATH += ';C:\\Program Files'\n",
+			expectedOutput: "$env:PATH += ';C:\\Program Files'\noh-my-posh init pwsh | Invoke-Expression\n",
+			expectedUpdate: true,
+		},
 	}
 
 	for _, tt := range tests {

website/docs/dsc.md

@@ -244,6 +244,7 @@ resources:
       states:
         - name: pwsh
           command: oh-my-posh init pwsh --config ~/mytheme.omp.json
+          skipExistingInit: true
 ```
 
 Apply with:
@@ -391,6 +392,13 @@ Manages shell initialization.
 
 **Properties:**
 
+- `states` (array): List of shell initialization states
+  - `name` (string): Shell name
+  - `command` (string): `oh-my-posh init` command to apply
+  - `skipExistingInit` (boolean): When `true`, any existing `oh-my-posh init` line is treated as compliant and left unchanged
+
+**Properties:**
+
 - `states` (array): List of shell configurations
   - `name` (string): Shell name (`bash`, `zsh`, `pwsh`, `fish`, etc.)
   - `command` (string): Oh My Posh initialization command