ChunkMatches: drop trailing newline

.github/workflows/ci.yml

@@ -23,11 +23,15 @@ jobs:
     name: fuzz test
     runs-on: ubuntu-latest
     steps:
-      - uses: jidicula/go-fuzz-action@4f24eed45b25214f31a9fe035ca68ea2c88c6a13 # v1.2.0
+      # Pinned a commit to make go version configurable.
+      # This should be safe to upgrade once this commit is in a released version:
+      # https://github.com/jidicula/go-fuzz-action/commit/23cc553941669144159507e2cccdbb4afc5b3076
+      - uses: jidicula/go-fuzz-action@0206b61afc603b665297621fa5e691b1447a5e57
         with:
           packages: 'github.com/sourcegraph/zoekt' # This is the package where the Protobuf round trip tests are defined
           fuzz-time: 30s
           fuzz-minimize-time: 1m
+          go-version: '1.21'
 
   shellcheck:
     name: shellcheck

contentprovider.go

@@ -454,6 +454,18 @@ func (nls newlines) getLines(data []byte, low, high int) []byte {
 	lowStart, _ := nls.lineBounds(low)
 	_, highEnd := nls.lineBounds(high - 1)
 
+	// Drop any trailing newline. Editors do not treat a trailing newline as
+	// the start of a new line, so we should not either. lineBounds clamps to
+	// len(data) when an out-of-bounds line is requested.
+	//
+	// As an example, if we request lines 1-5 from a file with contents
+	// `one\ntwo\nthree\n`, we should return `one\ntwo\nthree` because those are
+	// the three "lines" in the file, separated by newlines.
+	if highEnd == uint32(len(data)) && bytes.HasSuffix(data, []byte{'\n'}) {
+		highEnd = highEnd - 1
+		lowStart = min(lowStart, highEnd)
+	}
+
 	return data[lowStart:highEnd]
 }
 
@@ -681,7 +693,6 @@ func sectionSlice(data []byte, sec DocumentSection) []byte {
 	return data[sec.Start:sec.End]
 }
 
-
 // scoreSymbolKind boosts a match based on the combination of language, symbol
 // and kind. The language string comes from go-enry, the symbol and kind from
 // ctags.

contentprovider_test.go

@@ -32,7 +32,8 @@ func TestGetLines(t *testing.T) {
 	for _, content := range contents {
 		t.Run("", func(t *testing.T) {
 			newLines := getNewlines(content)
-			lines := bytes.Split(content, []byte{'\n'}) // TODO does split group consecutive sep?
+			// Trim the last newline before splitting because a trailing newline does not constitute a new line
+			lines := bytes.Split(bytes.TrimSuffix(content, []byte{'\n'}), []byte{'\n'})
 			wantGetLines := func(low, high int) []byte {
 				low--
 				high--

web/e2e_test.go

@@ -560,7 +560,10 @@ func TestContextLines(t *testing.T) {
 						// Returns 3 instead of 4 new line characters since we swallow
 						// the last new line in Before, Fragments and After.
 						Before: "\n\n\n",
-						After:  "\n\n\n",
+						// Returns 2 instead of 3 new line characters since a
+						// trailing newline at the end of the file does not
+						// constitue a new line.
+						After: "\n\n",
 					},
 				},
 			},