Handle breaking change in ChunkMatch newlines

Previously, zoekt made the curious choice to not include trailing
newline characters in each chunk it served in its API, in spite of the
posix definition of a line including the trailing newline character,
which is respected in many line-oriented unix tools like grep/ripgrep,
etc.

This mistake has finally been corrected! But it is a breakage that we
have to handle here. I've updated the tests to reflect the kind of data
that zoekt is actually serving now.

See sourcegraph/zoekt#747.

.changeset/dirty-windows-marry.md

@@ -0,0 +1,5 @@
+---
+"neogrok": patch
+---
+
+Handle breaking change in ChunkMatch newlines

src/lib/server/content-parser.test.ts

@@ -37,23 +37,23 @@ describe("parseFileNameMatch", () => {
 describe("parseChunkMatch", () => {
   it("parses chunk matches", () => {
     // Single line.
-    expect(parseChunkMatch(Buffer.from("foo"), [])).toEqual([
+    expect(parseChunkMatch(Buffer.from("foo\n"), [])).toEqual([
       { text: "foo", matchRanges: [] },
     ]);
-    expect(parseChunkMatch(Buffer.from("foo"), [{ start: 0, end: 3 }])).toEqual(
-      [{ text: "foo", matchRanges: [{ start: 0, end: 3 }] }],
-    );
-    expect(parseChunkMatch(Buffer.from("foo"), [{ start: 0, end: 2 }])).toEqual(
-      [{ text: "foo", matchRanges: [{ start: 0, end: 2 }] }],
-    );
-    expect(parseChunkMatch(Buffer.from("foo"), [{ start: 1, end: 3 }])).toEqual(
-      [{ text: "foo", matchRanges: [{ start: 1, end: 3 }] }],
-    );
-    expect(parseChunkMatch(Buffer.from("foo"), [{ start: 1, end: 2 }])).toEqual(
-      [{ text: "foo", matchRanges: [{ start: 1, end: 2 }] }],
-    );
     expect(
-      parseChunkMatch(Buffer.from("foo"), [
+      parseChunkMatch(Buffer.from("foo\n"), [{ start: 0, end: 3 }]),
+    ).toEqual([{ text: "foo", matchRanges: [{ start: 0, end: 3 }] }]);
+    expect(
+      parseChunkMatch(Buffer.from("foo\n"), [{ start: 0, end: 2 }]),
+    ).toEqual([{ text: "foo", matchRanges: [{ start: 0, end: 2 }] }]);
+    expect(
+      parseChunkMatch(Buffer.from("foo\n"), [{ start: 1, end: 3 }]),
+    ).toEqual([{ text: "foo", matchRanges: [{ start: 1, end: 3 }] }]);
+    expect(
+      parseChunkMatch(Buffer.from("foo\n"), [{ start: 1, end: 2 }]),
+    ).toEqual([{ text: "foo", matchRanges: [{ start: 1, end: 2 }] }]);
+    expect(
+      parseChunkMatch(Buffer.from("foo\n"), [
         { start: 1, end: 2 },
         { start: 2, end: 3 },
       ]),
@@ -68,42 +68,42 @@ describe("parseChunkMatch", () => {
     ]);
 
     // Multi-line.
-    expect(parseChunkMatch(Buffer.from("foo\n"), [])).toEqual([
+    expect(parseChunkMatch(Buffer.from("foo\n\n"), [])).toEqual([
       { text: "foo", matchRanges: [] },
       { text: "", matchRanges: [] },
     ]);
     expect(
-      parseChunkMatch(Buffer.from("foo\n"), [{ start: 0, end: 3 }]),
+      parseChunkMatch(Buffer.from("foo\n\n"), [{ start: 0, end: 3 }]),
     ).toEqual([
       { text: "foo", matchRanges: [{ start: 0, end: 3 }] },
       { text: "", matchRanges: [] },
     ]);
     expect(
-      parseChunkMatch(Buffer.from("foo\n"), [{ start: 0, end: 4 }]),
+      parseChunkMatch(Buffer.from("foo\n\n"), [{ start: 0, end: 4 }]),
     ).toEqual([
       { text: "foo", matchRanges: [{ start: 0, end: 3 }] },
       { text: "", matchRanges: [] },
     ]);
 
-    expect(parseChunkMatch(Buffer.from("foo\nbar"), [])).toEqual([
+    expect(parseChunkMatch(Buffer.from("foo\nbar\n"), [])).toEqual([
       { text: "foo", matchRanges: [] },
       { text: "bar", matchRanges: [] },
     ]);
     expect(
-      parseChunkMatch(Buffer.from("foo\nbar"), [{ start: 0, end: 3 }]),
+      parseChunkMatch(Buffer.from("foo\nbar\n"), [{ start: 0, end: 3 }]),
     ).toEqual([
       { text: "foo", matchRanges: [{ start: 0, end: 3 }] },
       { text: "bar", matchRanges: [] },
     ]);
     expect(
-      parseChunkMatch(Buffer.from("foo\nbar"), [{ start: 0, end: 4 }]),
+      parseChunkMatch(Buffer.from("foo\nbar\n"), [{ start: 0, end: 4 }]),
     ).toEqual([
       { text: "foo", matchRanges: [{ start: 0, end: 3 }] },
       { text: "bar", matchRanges: [] },
     ]);
 
     expect(
-      parseChunkMatch(Buffer.from("foo\nbar"), [
+      parseChunkMatch(Buffer.from("foo\nbar\n"), [
         { start: 0, end: 1 },
         { start: 2, end: 5 },
       ]),

src/lib/server/content-parser.ts

@@ -132,11 +132,10 @@ Array<ContentLine> => {
     }
   }
 
-  // Conclude the current line. Note that if `currentLineText` is length 0,
-  // that is still semantically a line, namely an empty line. `Content` never
-  // naturally has a trailing newline; if there's a newline at the last byte,
-  // this indicates that there is a final line that is empty.
-  lines.push({ text: currentLineText, matchRanges: currentLineMatchRanges });
+  if (currentLineText.length > 0) {
+    // Conclude the current line.
+    lines.push({ text: currentLineText, matchRanges: currentLineMatchRanges });
+  }
 
   return lines;
 };