fix(longevity): the alg fails on multiple of insertions and deletions (APP-95)

Author: asurkov

src/main/kotlin/app/hashers/CodeLongevity.kt

@@ -233,35 +233,18 @@ class CodeLongevity(private val localRepo: LocalRepo,
                 }
                 val lines = files.get(path)!!
 
-                // Update the lines array to match the diff's edit list changes.
-                // Traverse the edit list backwards to keep indices of the edit
-                // list and the lines array in sync.
-                val editList = df.toFileHeader(diff).toEditList().asReversed()
-                for (edit in editList) {
-                    val delStart = edit.getBeginA()
-                    val delEnd = edit.getEndA()
-                    val delCount = edit.getLengthA()
-                    var insStart = edit.getBeginB()
-                    var insEnd = edit.getEndB()
+                // Update the lines array according to diff insertions.
+                // Traverse the edit list backwards to keep indices of
+                // the edit list and the lines array in sync.
+                val editList = df.toFileHeader(diff).toEditList()
+                for (edit in editList.asReversed()) {
+                    // Insertion case: track the lines.
                     val insCount = edit.getLengthB()
-                    Logger.debug("del ($delStart, $delEnd), "
-                        + "ins ($insStart, $insEnd)")
-
-                    // Deletion case. Chase down the deleted lines through the
-                    // history.
-                    if (delCount > 0) {
-                        var tmpLines = ArrayList<RevCommitLine>(delCount)
-                        for (idx in delStart .. delEnd - 1) {
-                            tmpLines.add(RevCommitLine(commit, oldPath, idx))
-                        }
-                        
-                        // TODO(alex): Approve code change.
-                        // delStart index caused IndexOutOfBoundException.
-                        lines.addAll(tmpLines)
-                    }
-
-                    // Insertion case. Track it.
                     if (insCount > 0) {
+                        var insStart = edit.getBeginB()
+                        var insEnd = edit.getEndB()
+                        Logger.debug("ins ($insStart, $insEnd)")
+
                         val fileLoader = repo.open(newId)
                         val fileText = RawText(fileLoader.getBytes())
 
@@ -276,6 +259,24 @@ class CodeLongevity(private val localRepo: LocalRepo,
                     }
                 }
 
+                // Update the lines array according to diff deletions.
+                for (edit in editList) {
+                    // Deletion case. Chase down the deleted lines through the
+                    // history.
+                    val delCount = edit.getLengthA()
+                    if (delCount > 0) {
+                        val delStart = edit.getBeginA()
+                        val delEnd = edit.getEndA()
+                        Logger.debug("del ($delStart, $delEnd)")
+
+                        var tmpLines = ArrayList<RevCommitLine>(delCount)
+                        for (idx in delStart .. delEnd - 1) {
+                            tmpLines.add(RevCommitLine(commit, oldPath, idx))
+                        }
+                        lines.addAll(delStart, tmpLines)
+                    }
+                }
+
                 // File was renamed, tweak the files map.
                 if (diff.changeType == DiffEntry.ChangeType.RENAME) {
                     files.set(oldPath, files.remove(newPath)!!)

src/test/kotlin/test/tests/hashers/CodeLongevityTest.kt

@@ -148,4 +148,86 @@ class CodeLongevityTest : Spek({
             testRepo.destroy()
         }
     }
+
+    given("'test group #2'") {
+
+        val testRepoPath = "../testrepo2"
+        val testRepo = TestRepo(testRepoPath)
+        val fileName = "test1.txt"
+
+        // t2.1: initial insertion
+        val fileContent = listOf(
+          "line1",
+          "line2",
+          "line3",
+          "line4",
+          "line4",
+          "line5",
+          "line6",
+          "line7",
+          "line8",
+          "line9",
+          "line10",
+          "line11",
+          "line12",
+          "line13",
+          "line14",
+          "line15",
+          "line16",
+          "line17",
+          "line18"
+        )
+        testRepo.newFile(fileName, fileContent)
+        val rev1 = testRepo.commit("inital commit")
+        val lines1 = CodeLongevity(
+            LocalRepo(testRepoPath), Repo(), MockApi(), testRepo.git).compute()
+
+        it("'t2.1: initial insertion'") {
+            assertEquals(fileContent.size, lines1.size)
+            for (idx in 0 .. fileContent.size - 1) {
+                assertCodeLine(fileContent[idx],
+                               rev1, fileName, idx,
+                               rev1, fileName, idx,
+                               lines1[idx])
+            }
+        }
+
+        // t2.2: ins+del
+        testRepo.deleteLines(fileName, 15, 18)
+        testRepo.deleteLines(fileName, 9, 11)
+        testRepo.deleteLines(fileName, 3, 5)
+        testRepo.insertLines(fileName, 3, listOf("Proof addition 1"))
+        testRepo.insertLines(fileName, 7, listOf("Proof addition 2"))
+        testRepo.insertLines(fileName, 11, listOf("Proof addition 3"))
+        val rev2 = testRepo.commit("insert+delete")
+
+        val lines2 = CodeLongevity(
+            LocalRepo(testRepoPath), Repo(), MockApi(), testRepo.git).compute()
+
+        it("'t2.2: ins+del'") {
+            assertEquals(22, lines2.size)
+            assertCodeLine("Proof addition 3", rev2, fileName, 11,
+                           rev2, fileName, 11, lines2[0])
+            assertCodeLine("Proof addition 2", rev2, fileName, 7,
+                           rev2, fileName, 7, lines2[1])
+            assertCodeLine("Proof addition 1", rev2, fileName, 3,
+                           rev2, fileName, 3, lines2[2])
+            assertCodeLine("line1", rev1, fileName, 0,
+                           rev2, fileName, 0, lines2[3])
+            assertCodeLine("line2",
+                           rev1, fileName, 1, rev2, fileName, 1, lines2[4])
+            assertCodeLine("line3",
+                           rev1, fileName, 2, rev2, fileName, 2, lines2[5])
+            assertCodeLine("line4",
+                           rev1, fileName, 3, rev2, fileName, 3, lines2[6])
+            assertCodeLine("line4",
+                           rev1, fileName, 4, rev2, fileName, 4, lines2[7])
+            assertCodeLine("line5",
+                           rev1, fileName, 5, rev2, fileName, 5, lines2[8])
+        }
+
+        afterGroup {
+            testRepo.destroy()
+        }
+    }
 })

src/test/kotlin/test/utils/TestRepo.kt

@@ -53,6 +53,7 @@ class TestRepo(val repoPath: String) {
 
         var lineIdx = 0
         for (line in reader.lines()) {
+            // Insertion case
             if (lineIdx == insIndex) {
                 for (insLine in insLines) {
                     tmpWriter.write(insLine)
@@ -64,6 +65,15 @@ class TestRepo(val repoPath: String) {
             tmpWriter.newLine()
             lineIdx++
         }
+
+        // Append case
+        if (lineIdx == insIndex) {
+            for (insLine in insLines) {
+                tmpWriter.write(insLine)
+                tmpWriter.newLine()
+            }
+        }
+
         tmpWriter.flush()
 
         val writer = FileWriter(file)