Allow whitespace lines when calculating edit indentation (#2511)

When calculating the edit indentation we want to skip empty lines, but
whitespace lines we should actually use.

## Checklist

- [x] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [/] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [/] I have not broken the cheatsheet

---------

Co-authored-by: Pokey Rule <[email protected]>

data/fixtures/recorded/actions/drinkLine2.yml

@@ -0,0 +1,37 @@
+languageId: plaintext
+command:
+  version: 7
+  spokenForm: drink line
+  action:
+    name: editNewLineBefore
+    target:
+      type: primitive
+      modifiers:
+        - type: containingScope
+          scopeType: {type: line}
+  usePrePhraseSnapshot: true
+initialState:
+  documentContents: |-
+    def my_funk():
+        
+        pass
+  selections:
+    - anchor: {line: 1, character: 4}
+      active: {line: 1, character: 4}
+  marks: {}
+finalState:
+  documentContents: |-
+    def my_funk():
+        
+        
+        pass
+  selections:
+    - anchor: {line: 1, character: 4}
+      active: {line: 1, character: 4}
+  thatMark:
+    - type: UntypedTarget
+      contentRange:
+        start: {line: 2, character: 0}
+        end: {line: 2, character: 4}
+      isReversed: false
+      hasExplicitRange: true

data/fixtures/recorded/actions/pourFunk.yml

@@ -0,0 +1,38 @@
+languageId: typescript
+command:
+  version: 7
+  spokenForm: pour funk
+  action:
+    name: editNewLineAfter
+    target:
+      type: primitive
+      modifiers:
+        - type: containingScope
+          scopeType: {type: namedFunction}
+  usePrePhraseSnapshot: true
+initialState:
+  documentContents: |2-
+        function foo() {
+      
+        }
+  selections:
+    - anchor: {line: 1, character: 2}
+      active: {line: 1, character: 2}
+  marks: {}
+finalState:
+  documentContents: |2-
+        function foo() {
+      
+        }
+
+        
+  selections:
+    - anchor: {line: 4, character: 4}
+      active: {line: 4, character: 4}
+  thatMark:
+    - type: UntypedTarget
+      contentRange:
+        start: {line: 0, character: 4}
+        end: {line: 2, character: 5}
+      isReversed: false
+      hasExplicitRange: true

data/fixtures/recorded/actions/pourLine2.yml

@@ -0,0 +1,37 @@
+languageId: plaintext
+command:
+  version: 7
+  spokenForm: pour line
+  action:
+    name: editNewLineAfter
+    target:
+      type: primitive
+      modifiers:
+        - type: containingScope
+          scopeType: {type: line}
+  usePrePhraseSnapshot: true
+initialState:
+  documentContents: |-
+    def my_funk():
+        
+        pass
+  selections:
+    - anchor: {line: 1, character: 4}
+      active: {line: 1, character: 4}
+  marks: {}
+finalState:
+  documentContents: |-
+    def my_funk():
+        
+        
+        pass
+  selections:
+    - anchor: {line: 2, character: 4}
+      active: {line: 2, character: 4}
+  thatMark:
+    - type: UntypedTarget
+      contentRange:
+        start: {line: 1, character: 0}
+        end: {line: 1, character: 4}
+      isReversed: false
+      hasExplicitRange: true

packages/cursorless-engine/src/processTargets/targets/DestinationImpl.ts

@@ -185,9 +185,19 @@ function getIndentationString(editor: TextEditor, range: Range) {
   for (let i = range.start.line; i <= range.end.line; ++i) {
     const line = editor.document.lineAt(i);
     if (
-      !line.isEmptyOrWhitespace &&
-      line.firstNonWhitespaceCharacterIndex < length
+      line.range.isEmpty ||
+      (line.isEmptyOrWhitespace && !range.isSingleLine)
     ) {
+      // Skip empty lines. If the range is a single line, we want to include the
+      // indentation of the line even if it is all whitespace so that you can
+      // "drink line" on an indented but empty line and get the same
+      // indentation. If the range is not a single line, we want to skip any
+      // lines that are all whitespace to avoid including a random line of
+      // whitespace in the indentation.
+      continue;
+    }
+
+    if (line.firstNonWhitespaceCharacterIndex < length) {
       length = line.firstNonWhitespaceCharacterIndex;
       indentationString = line.text.slice(0, length);
     }