feat(context): Add intelligent DiffProcessor to summarize and prioritize git diffs and integrate it into the commit context pipeline

2025-11-04 02:19:57 +00:00
parent f84a65217d
commit 4bf0c02618
7 changed files with 698 additions and 13 deletions
--- a/test/test.diffprocessor.node.ts
+++ b/test/test.diffprocessor.node.ts
@@ -0,0 +1,304 @@
+import { tap, expect } from '@git.zone/tstest/tapbundle';
+import { DiffProcessor } from '../ts/context/diff-processor.js';
+
+// Sample diff strings for testing
+const createSmallDiff = (filepath: string, addedLines = 5, removedLines = 3): string => {
+  const lines: string[] = [];
+  lines.push(`--- a/${filepath}`);
+  lines.push(`+++ b/${filepath}`);
+  lines.push(`@@ -1,10 +1,12 @@`);
+
+  for (let i = 0; i < removedLines; i++) {
+    lines.push(`-removed line ${i + 1}`);
+  }
+
+  for (let i = 0; i < addedLines; i++) {
+    lines.push(`+added line ${i + 1}`);
+  }
+
+  lines.push(' unchanged line');
+
+  return lines.join('\n');
+};
+
+const createMediumDiff = (filepath: string): string => {
+  const lines: string[] = [];
+  lines.push(`--- a/${filepath}`);
+  lines.push(`+++ b/${filepath}`);
+  lines.push(`@@ -1,100 +1,150 @@`);
+
+  // 150 lines of changes
+  for (let i = 0; i < 75; i++) {
+    lines.push(`+added line ${i + 1}`);
+  }
+
+  for (let i = 0; i < 75; i++) {
+    lines.push(`-removed line ${i + 1}`);
+  }
+
+  return lines.join('\n');
+};
+
+const createLargeDiff = (filepath: string): string => {
+  const lines: string[] = [];
+  lines.push(`--- a/${filepath}`);
+  lines.push(`+++ b/${filepath}`);
+  lines.push(`@@ -1,1000 +1,1500 @@`);
+
+  // 2500 lines of changes
+  for (let i = 0; i < 1250; i++) {
+    lines.push(`+added line ${i + 1}`);
+  }
+
+  for (let i = 0; i < 1250; i++) {
+    lines.push(`-removed line ${i + 1}`);
+  }
+
+  return lines.join('\n');
+};
+
+const createDeletedFileDiff = (filepath: string): string => {
+  return `--- a/${filepath}
+++ /dev/null
+@@ -1,5 +0,0 @@
+-deleted line 1
+-deleted line 2
+-deleted line 3
+-deleted line 4
+-deleted line 5`;
+};
+
+const createAddedFileDiff = (filepath: string): string => {
+  return `--- /dev/null
+++ b/${filepath}
+@@ -0,0 +1,5 @@
+added line 1
+added line 2
+added line 3
+added line 4
+added line 5`;
+};
+
+tap.test('DiffProcessor should parse small diff correctly', async () => {
+  const processor = new DiffProcessor();
+  const smallDiff = createSmallDiff('src/test.ts', 5, 3);
+
+  const result = processor.processDiffs([smallDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  expect(result.fullDiffs.length).toEqual(1);
+  expect(result.summarizedDiffs.length).toEqual(0);
+  expect(result.metadataOnly.length).toEqual(0);
+  expect(result.totalTokens).toBeGreaterThan(0);
+});
+
+tap.test('DiffProcessor should summarize medium diff', async () => {
+  const processor = new DiffProcessor();
+  const mediumDiff = createMediumDiff('src/medium-file.ts');
+
+  const result = processor.processDiffs([mediumDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  expect(result.fullDiffs.length).toEqual(0);
+  expect(result.summarizedDiffs.length).toEqual(1);
+  expect(result.metadataOnly.length).toEqual(0);
+
+  // Verify the summarized diff contains the sample
+  const formatted = processor.formatForContext(result);
+  expect(formatted).toInclude('SUMMARIZED DIFFS');
+  expect(formatted).toInclude('lines omitted');
+});
+
+tap.test('DiffProcessor should handle large diff as metadata only', async () => {
+  const processor = new DiffProcessor();
+  const largeDiff = createLargeDiff('dist/bundle.js');
+
+  const result = processor.processDiffs([largeDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  expect(result.fullDiffs.length).toEqual(0);
+  expect(result.summarizedDiffs.length).toEqual(0);
+  expect(result.metadataOnly.length).toEqual(1);
+
+  const formatted = processor.formatForContext(result);
+  expect(formatted).toInclude('METADATA ONLY');
+  expect(formatted).toInclude('dist/bundle.js');
+});
+
+tap.test('DiffProcessor should prioritize source files over build artifacts', async () => {
+  const processor = new DiffProcessor();
+  const diffs = [
+    createSmallDiff('dist/bundle.js'),
+    createSmallDiff('src/important.ts'),
+    createSmallDiff('build/output.js'),
+    createSmallDiff('src/core.ts'),
+  ];
+
+  const result = processor.processDiffs(diffs);
+
+  expect(result.totalFiles).toEqual(4);
+
+  // Source files should be included fully first
+  const formatted = processor.formatForContext(result);
+  const srcImportantIndex = formatted.indexOf('src/important.ts');
+  const srcCoreIndex = formatted.indexOf('src/core.ts');
+  const distBundleIndex = formatted.indexOf('dist/bundle.js');
+  const buildOutputIndex = formatted.indexOf('build/output.js');
+
+  // Source files should appear before build artifacts
+  expect(srcImportantIndex).toBeLessThan(distBundleIndex);
+  expect(srcCoreIndex).toBeLessThan(buildOutputIndex);
+});
+
+tap.test('DiffProcessor should respect token budget', async () => {
+  const processor = new DiffProcessor({
+    maxDiffTokens: 500, // Very small budget to force metadata-only
+  });
+
+  // Create multiple large diffs that will exceed budget
+  const diffs = [
+    createLargeDiff('src/file1.ts'),
+    createLargeDiff('src/file2.ts'),
+    createLargeDiff('src/file3.ts'),
+    createLargeDiff('src/file4.ts'),
+  ];
+
+  const result = processor.processDiffs(diffs);
+
+  expect(result.totalTokens).toBeLessThanOrEqual(500);
+  // With such a small budget and large files, most should be metadata only
+  expect(result.metadataOnly.length).toBeGreaterThanOrEqual(2);
+});
+
+tap.test('DiffProcessor should handle deleted files', async () => {
+  const processor = new DiffProcessor();
+  const deletedDiff = createDeletedFileDiff('src/old-file.ts');
+
+  const result = processor.processDiffs([deletedDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  // Small deleted file should be included fully
+  expect(result.fullDiffs.length).toEqual(1);
+
+  const formatted = processor.formatForContext(result);
+  expect(formatted).toInclude('src/old-file.ts');
+  // Verify the file appears in the output
+  expect(formatted).toInclude('FULL DIFFS');
+});
+
+tap.test('DiffProcessor should handle added files', async () => {
+  const processor = new DiffProcessor();
+  const addedDiff = createAddedFileDiff('src/new-file.ts');
+
+  const result = processor.processDiffs([addedDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  // Small added file should be included fully
+  expect(result.fullDiffs.length).toEqual(1);
+
+  const formatted = processor.formatForContext(result);
+  expect(formatted).toInclude('src/new-file.ts');
+  // Verify the file appears in the output
+  expect(formatted).toInclude('FULL DIFFS');
+});
+
+tap.test('DiffProcessor should handle mixed file sizes', async () => {
+  const processor = new DiffProcessor();
+  const diffs = [
+    createSmallDiff('src/small.ts'),
+    createMediumDiff('src/medium.ts'),
+    createLargeDiff('dist/large.js'),
+  ];
+
+  const result = processor.processDiffs(diffs);
+
+  expect(result.totalFiles).toEqual(3);
+  expect(result.fullDiffs.length).toEqual(1); // small file
+  expect(result.summarizedDiffs.length).toEqual(1); // medium file
+  expect(result.metadataOnly.length).toEqual(1); // large file
+
+  const formatted = processor.formatForContext(result);
+  expect(formatted).toInclude('FULL DIFFS (1 files)');
+  expect(formatted).toInclude('SUMMARIZED DIFFS (1 files)');
+  expect(formatted).toInclude('METADATA ONLY (1 files)');
+});
+
+tap.test('DiffProcessor should handle empty diff array', async () => {
+  const processor = new DiffProcessor();
+  const result = processor.processDiffs([]);
+
+  expect(result.totalFiles).toEqual(0);
+  expect(result.fullDiffs.length).toEqual(0);
+  expect(result.summarizedDiffs.length).toEqual(0);
+  expect(result.metadataOnly.length).toEqual(0);
+  expect(result.totalTokens).toEqual(0);
+});
+
+tap.test('DiffProcessor should generate comprehensive summary', async () => {
+  const processor = new DiffProcessor();
+  const diffs = [
+    createSmallDiff('src/file1.ts'),
+    createSmallDiff('src/file2.ts'),
+    createMediumDiff('src/file3.ts'),
+    createLargeDiff('dist/bundle.js'),
+  ];
+
+  const result = processor.processDiffs(diffs);
+  const formatted = processor.formatForContext(result);
+
+  expect(formatted).toInclude('GIT DIFF SUMMARY');
+  expect(formatted).toInclude('Files changed: 4 total');
+  expect(formatted).toInclude('included in full');
+  expect(formatted).toInclude('summarized');
+  expect(formatted).toInclude('metadata only');
+  expect(formatted).toInclude('Estimated tokens:');
+  expect(formatted).toInclude('END OF GIT DIFF');
+});
+
+tap.test('DiffProcessor should handle custom options', async () => {
+  const processor = new DiffProcessor({
+    maxDiffTokens: 50000,
+    smallFileLines: 30,
+    mediumFileLines: 150,
+    sampleHeadLines: 10,
+    sampleTailLines: 10,
+  });
+
+  const mediumDiff = createMediumDiff('src/file.ts'); // 150 lines
+  const result = processor.processDiffs([mediumDiff]);
+
+  // With custom settings, this should be summarized (exactly at the mediumFileLines threshold)
+  expect(result.summarizedDiffs.length).toEqual(1);
+});
+
+tap.test('DiffProcessor should prioritize test files appropriately', async () => {
+  const processor = new DiffProcessor();
+  const diffs = [
+    createSmallDiff('src/core.ts'),
+    createSmallDiff('test/core.test.ts'),
+    createSmallDiff('config.json'),
+  ];
+
+  const result = processor.processDiffs(diffs);
+  const formatted = processor.formatForContext(result);
+
+  // Source files should come before test files
+  const srcIndex = formatted.indexOf('src/core.ts');
+  const testIndex = formatted.indexOf('test/core.test.ts');
+
+  expect(srcIndex).toBeLessThan(testIndex);
+});
+
+tap.test('DiffProcessor should handle files with no changes gracefully', async () => {
+  const processor = new DiffProcessor();
+  const emptyDiff = `--- a/src/file.ts
+++ b/src/file.ts
+@@ -1,1 +1,1 @@`;
+
+  const result = processor.processDiffs([emptyDiff]);
+
+  expect(result.totalFiles).toEqual(1);
+  expect(result.fullDiffs.length).toEqual(1); // Still included as a small file
+});
+
+export default tap.start();