(GH-1437) Fix detecting contiguous comment blocks and regions

src/features/Folding.ts

@@ -173,6 +173,22 @@ interface ILineNumberRangeList extends Array<LineNumberRange> { }
 export class FoldingProvider implements vscode.FoldingRangeProvider {
     private powershellGrammar: IGrammar;
 
+    /**
+     * These regular expressions are used to match lines which mark the start and end of region comment in a PowerShell
+     * script. They are based on the defaults in the VS Code Language Configuration at;
+     * https://github.com/Microsoft/vscode/blob/64186b0a26/extensions/powershell/language-configuration.json#L26-L31
+     */
+    private readonly startRegionText = /^\s*#region\b/i;
+    private readonly endRegionText = /^\s*#endregion\b/i;
+    /**
+     * This regular expressions is used to detect a line comment (as opposed to an inline comment), that is not a region
+     * block directive i.e.
+     * - No text between the beginning of the line and `#`
+     * - Comment does start with region
+     * - Comment does start with endregion
+     */
+    private readonly lineCommentText = /\s*#(?!region\b|endregion\b)/i;
+
     constructor(
         powershellGrammar: IGrammar,
     ) {
@@ -310,34 +326,16 @@ export class FoldingProvider implements vscode.FoldingRangeProvider {
     }
 
     /**
-     * Given a zero based offset, find the line text preceeding it in the document
+     * Given a zero based offset, find the line in the document
      * @param offset   Zero based offset in the document
      * @param document The source text document
-     * @returns        The line text preceeding the offset, not including the preceeding Line Feed
+     * @returns        The line at the offset
      */
-    private preceedingText(
+    private lineAtOffset(
         offset: number,
         document: vscode.TextDocument,
-    ): string {
-        const endPos = document.positionAt(offset);
-        const startPos = endPos.translate(0, -endPos.character);
-
-        return document.getText(new vscode.Range(startPos, endPos));
-    }
-
-    /**
-     * Given a zero based offset, find the line text after it in the document
-     * @param offset   Zero based offset in the document
-     * @param document The source text document
-     * @returns        The line text after the offset, not including the subsequent Line Feed
-     */
-    private subsequentText(
-        offset: number,
-        document: vscode.TextDocument,
-    ): string {
-        const startPos: vscode.Position = document.positionAt(offset);
-        const endPos: vscode.Position = document.lineAt(document.positionAt(offset)).range.end;
-        return document.getText(new vscode.Range(startPos, endPos));
+    ): vscode.TextLine {
+        return document.lineAt(document.positionAt(offset));
     }
 
     /**
@@ -353,19 +351,16 @@ export class FoldingProvider implements vscode.FoldingRangeProvider {
         document: vscode.TextDocument,
     ): ILineNumberRangeList {
         const result = [];
-
-        const emptyLine = /^\s*$/;
-
         let startLine: number = -1;
         let nextLine: number = -1;
 
         tokens.forEach((token) => {
             if (token.scopes.indexOf("punctuation.definition.comment.powershell") !== -1) {
+                const line: vscode.TextLine = this.lineAtOffset(token.startIndex, document);
                 // The punctuation.definition.comment.powershell token matches new-line comments
-                // and inline comments e.g. `$x = 'foo' # inline comment`.  We are only interested
-                // in comments which begin the line i.e. no preceeding text
-                if (emptyLine.test(this.preceedingText(token.startIndex, document))) {
-                    const lineNum = document.positionAt(token.startIndex).line;
+                // and inline comments e.g. `$x = 'foo' # inline comment`.
+                if (this.lineCommentText.test(line.text)) {
+                    const lineNum = line.lineNumber;
                     // A simple pattern for keeping track of contiguous numbers in a known sorted array
                     if (startLine === -1) {
                         startLine = lineNum;
@@ -420,21 +415,14 @@ export class FoldingProvider implements vscode.FoldingRangeProvider {
         document: vscode.TextDocument,
     ): ITokenList {
         const result = [];
-
-        const emptyLine = /^\s*$/;
-        const startRegionText = /^#region\b/i;
-        const endRegionText = /^#endregion\b/i;
-
         tokens.forEach((token) => {
             if (token.scopes.indexOf("punctuation.definition.comment.powershell") !== -1) {
-                if (emptyLine.test(this.preceedingText(token.startIndex, document))) {
-                    const commentText = this.subsequentText(token.startIndex, document);
-                    if (startRegionText.test(commentText)) {
-                        result.push(this.addTokenScope(token, "custom.start.region"));
-                    }
-                    if (endRegionText.test(commentText)) {
-                        result.push(this.addTokenScope(token, "custom.end.region"));
-                    }
+                const line: string = this.lineAtOffset(token.startIndex, document).text;
+                if (this.startRegionText.test(line)) {
+                    result.push(this.addTokenScope(token, "custom.start.region"));
+                }
+                if (this.endRegionText.test(line)) {
+                    result.push(this.addTokenScope(token, "custom.end.region"));
                 }
             }
         });

test/features/folding.test.ts

@@ -50,6 +50,9 @@ suite("Features", () => {
                 { start: 41, end: 45, kind: 3 },
                 { start: 51, end: 53, kind: 3 },
                 { start: 56, end: 59, kind: 3 },
+                { start: 64, end: 66, kind: 1 },
+                { start: 67, end: 72, kind: 3 },
+                { start: 68, end: 70, kind: 1 },
             ];
 
             test("Can detect all of the foldable regions in a document with CRLF line endings", async () => {

test/fixtures/folding-crlf.ps1

@@ -59,3 +59,15 @@ double quoted herestrings should also fold
   'should fold2'
   )
 }
+
+# Make sure contiguous comment blocks can be folded properly
+
+# Comment Block 1
+# Comment Block 1
+# Comment Block 1
+#region Comment Block 3
+# Comment Block 2
+# Comment Block 2
+# Comment Block 2
+$something = $true
+#endregion Comment Block 3

test/fixtures/folding-lf.ps1

@@ -59,3 +59,15 @@ double quoted herestrings should also fold
   'should fold2'
   )
 }
+
+# Make sure contiguous comment blocks can be folded properly
+
+# Comment Block 1
+# Comment Block 1
+# Comment Block 1
+#region Comment Block 3
+# Comment Block 2
+# Comment Block 2
+# Comment Block 2
+$something = $true
+#endregion Comment Block 3