Dedent on else: and similar statements

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Unreleased
 
+* Dedent current line on `else`, `elif`, `except`, and `finally` statements
+    * ***NOTE:*** You no longer need to manually un-indent on these lines, just press `Enter` and it will be un-indented for you.
 * Don't dedent on keywords if they appear in triple quoted string.
 
 ### 0.8.1

README.md

@@ -8,7 +8,7 @@ Correct python indentation in Visual Studio Code. [See it on the VSCode Marketpl
 
 ## How it works
 
-Every time you press the `Enter` key in a python context, this extension will parse your python file up to the location of your cursor, and determine exactly how much the next line (or two in the case of hanging indents) should be indented. There are two main cases.
+Every time you press the `Enter` key in a python context, this extension will parse your python file up to the location of your cursor, and determine exactly how much the next line (or two in the case of hanging indents) should be indented and how much nearby lines should be un-indented. There are three main cases.
 
 ### Between bracket pairs
 
@@ -76,6 +76,12 @@ result = my_func(
     |x, y, z)
 ```
 
+### Keywords
+
+Some keywords in python imply certain indentation behaviors. For example, if there is a `return` statement, then we know the next line can be un-indented (or *de*dented) since no statements can follow a `return` in the same code block. Other keywords that follow the same pattern are `pass`, `break`, `continue`, and `raise`
+
+Similarly, if there is an `else:` on the current line, that the current line needs to be dedented, and the next line needs to be indented *relative to* the new position of the `else:`. Other keywords that follow the same pattern are `elif <stuff>:`, `except <stuff>:`, and `finally:`.
+
 ## Why is it needed?
 
 There are many related issues on GitHub ([[1]](https://github.com/Microsoft/vscode-python/issues/481), [[2]](https://github.com/Microsoft/python-language-server/issues/671), [[3]](https://github.com/Microsoft/vscode/issues/66235), [[4]](https://github.com/Microsoft/vscode-python/issues/684), [[5]](https://github.com/Microsoft/vscode-python/issues/539)) asking for improved python indentation in VS Code. It seems like the maintainers of the python extension at microsoft are not prioritizing indentation, since there has been no progress in the years since it was first asked for.

src/indent.ts

@@ -21,11 +21,17 @@ export function newlineAndIndent(
 
     try {
         if (textEditor.document.languageId === 'python') {
-            const indent = nextIndentationLevel(
-                textEditor.document.getText(
-                    new vscode.Range(0, 0, position.line, position.character)).split("\n"),
-                tabSize
-            );
+            const lines = textEditor.document.getText(
+                new vscode.Range(0, 0, position.line, position.character)).split("\n");
+            let indent = nextIndentationLevel(lines, tabSize);
+            const spacesToRemove = dedentCurrentLine(currentLine, tabSize);
+            if (spacesToRemove > 0) {
+                // don't dedent the current line if we already dedented it, e.g. after a "return"
+                if (!parseLines(lines.slice(0, -1)).dedentNext) {
+                    edit.delete(new vscode.Range(position.line, 0, position.line, spacesToRemove));
+                    indent = Math.max(indent - spacesToRemove, 0);
+                }
+            }
             hanging = shouldHang(currentLine, position.character);
             if (hanging === Hanging.Partial) {
                 toInsert = '\n' + ' '.repeat(indentationLevel(currentLine) + tabSize);
@@ -63,7 +69,7 @@ export function nextIndentationLevel(
         openBracketStack, lastClosedRow, lastColonRow, dedentNext
     } = parseOutput;
 
-    if (dedentNext  && !openBracketStack.length) {
+    if (dedentNext && !openBracketStack.length) {
         return indentationLevel(lines[row]) - tabSize;
     }
 
@@ -326,3 +332,15 @@ export function shouldHang(line: string, char: number): Hanging {
     }
     return Hanging.None;
 }
+
+// Returns the number of spaces that should be removed from the current line
+export function dedentCurrentLine(line: string, tabSize: number): number {
+    const dedentKeywords = ["elif", "else", "except", "finally"];
+    const trimmed = line.trim();
+    if (trimmed.endsWith(":")) {
+        if (dedentKeywords.some((keyword) => trimmed.startsWith(keyword))) {
+            return Math.min(tabSize, indentationLevel(line));
+        }
+    }
+    return 0;
+}

src/test/extension.test.ts

@@ -433,7 +433,7 @@ x = ['here(\\'(', 'is', 'a',\n\
             ));
         });
     });
-    suite("dedent", function () {
+    suite("dedent next line", function () {
         test("return", function () {
             assert.equal(0, indent.nextIndentationLevel(
                 [
@@ -527,4 +527,27 @@ x = ['here(\\'(', 'is', 'a',\n\
             ));
         });
     });
+    suite("dedent current line", function () {
+        test("normal else", function () {
+            assert.equal(4, indent.dedentCurrentLine("    else:", 4));
+        });
+        test("else with small tabsize", function () {
+            assert.equal(2, indent.dedentCurrentLine("    else:", 2));
+        });
+        test("else resulting in over dedentation", function () {
+            assert.equal(0, indent.dedentCurrentLine("else:", 4));
+        });
+        test("else resulting in over dedentation, 2", function () {
+            assert.equal(2, indent.dedentCurrentLine("  else:", 4));
+        });
+        test("elif", function () {
+            assert.equal(2, indent.dedentCurrentLine("    elif x == 5:", 2));
+        });
+        test("except", function () {
+            assert.equal(2, indent.dedentCurrentLine("    except ValueError:", 2));
+        });
+        test("finally", function () {
+            assert.equal(2, indent.dedentCurrentLine("    finally:", 2));
+        });
+    });
 });