Merge pull request #17662 from overleaf/em-handle-tcs-history

Reintroduce tracked changes handling in project-history

GitOrigin-RevId: f6d72fbffc9b2d2328edc35ffb3f328a31d95e6a

services/project-history/app/js/UpdateCompressor.js

@@ -1,6 +1,15 @@
+// @ts-check
+
 import OError from '@overleaf/o-error'
 import DMP from 'diff-match-patch'
 
+/**
+ * @typedef {import('./types').DeleteOp} DeleteOp
+ * @typedef {import('./types').InsertOp} InsertOp
+ * @typedef {import('./types').Op} Op
+ * @typedef {import('./types').Update} Update
+ */
+
 const MAX_TIME_BETWEEN_UPDATES = 60 * 1000 // one minute
 const MAX_UPDATE_SIZE = 2 * 1024 * 1024 // 2 MB
 const ADDED = 1
@@ -31,47 +40,87 @@ const mergeUpdatesWithOp = function (firstUpdate, secondUpdate, op) {
   return update
 }
 
-const adjustLengthByOp = function (length, op) {
-  if (op.i != null) {
-    return length + op.i.length
-  } else if (op.d != null) {
-    return length - op.d.length
-  } else if (op.c != null) {
+/**
+ * Adjust the given length to account for the given op
+ *
+ * The resulting length is the new length of the doc after the op is applied.
+ *
+ * @param {number} length
+ * @param {Op} op
+ * @param {object} opts
+ * @param {boolean} [opts.tracked] - whether or not the update is a tracked change
+ * @returns {number} the adjusted length
+ */
+function adjustLengthByOp(length, op, opts = {}) {
+  if ('i' in op && op.i != null) {
+    if (op.trackedDeleteRejection) {
+      // Tracked delete rejection: will be translated into a retain
+      return length
+    } else {
+      return length + op.i.length
+    }
+  } else if ('d' in op && op.d != null) {
+    if (opts.tracked && op.u == null) {
+      // Tracked delete: will be translated into a retain, except where it overlaps tracked inserts.
+      for (const change of op.trackedChanges ?? []) {
+        if (change.type === 'insert') {
+          length -= change.length
+        }
+      }
+      return length
+    } else {
+      return length - op.d.length
+    }
+  } else if ('c' in op && op.c != null) {
     return length
   } else {
     throw new OError('unexpected op type')
   }
 }
 
-// Updates come from the doc updater in format
-// {
-// 	op:   [ { ... op1 ... }, { ... op2 ... } ]
-// 	meta: { ts: ..., user_id: ... }
-// }
-// but it's easier to work with on op per update, so convert these updates to
-// our compressed format
-// [{
-// 	op: op1
-// 	meta: { ts: ..., user_id: ... }
-// }, {
-// 	op: op2
-// 	meta: { ts: ..., user_id: ... }
-// }]
+/**
+ * Updates come from the doc updater in format
+ * {
+ * 	op:   [ { ... op1 ... }, { ... op2 ... } ]
+ * 	meta: { ts: ..., user_id: ... }
+ * }
+ * but it's easier to work with on op per update, so convert these updates to
+ * our compressed format
+ * [{
+ * 	op: op1
+ * 	meta: { ts: ..., user_id: ... }
+ * }, {
+ * 	op: op2
+ * 	meta: { ts: ..., user_id: ... }
+ * }]
+ *
+ * @param {Update[]} updates
+ * @returns {Update[]} single op updates
+ */
 export function convertToSingleOpUpdates(updates) {
   const splitUpdates = []
   for (const update of updates) {
-    if (update.op == null) {
+    if (!('op' in update)) {
       // Not a text op, likely a project strucure op
       splitUpdates.push(update)
       continue
     }
     const ops = update.op
-    let { doc_length: docLength } = update.meta
+
+    let docLength = update.meta.history_doc_length ?? update.meta.doc_length
+    // Temporary fix for document-updater sending a length of -1 for empty
+    // documents. This can be removed after all queues have been flushed.
+    if (docLength === -1) {
+      docLength = 0
+    }
     for (const op of ops) {
       const splitUpdate = cloneWithOp(update, op)
       if (docLength != null) {
         splitUpdate.meta.doc_length = docLength
-        docLength = adjustLengthByOp(docLength, op)
+        docLength = adjustLengthByOp(docLength, op, {
+          tracked: update.meta.tc != null,
+        })
+        delete splitUpdate.meta.history_doc_length
       }
       splitUpdates.push(splitUpdate)
     }
@@ -146,13 +195,21 @@ export function compressUpdates(updates) {
   return compressedUpdates
 }
 
+/**
+ * If possible, merge two updates into a single update that has the same effect.
+ *
+ * It's useful to do some of this work at this point while we're dealing with
+ * document-updater updates. The deletes, in particular include the deleted
+ * text. This allows us to find pieces of inserts and deletes that cancel each
+ * other out because they insert/delete the exact same text. This compression
+ * makes the diff smaller.
+ */
 function _concatTwoUpdates(firstUpdate, secondUpdate) {
   // Previously we cloned firstUpdate and secondUpdate at this point but we
   // can skip this step because whenever they are returned with
   // modification there is always a clone at that point via
   // mergeUpdatesWithOp.
 
-  let offset
   if (firstUpdate.op == null || secondUpdate.op == null) {
     // Project structure ops
     return [firstUpdate, secondUpdate]
@@ -185,6 +242,45 @@ function _concatTwoUpdates(firstUpdate, secondUpdate) {
     return [firstUpdate, secondUpdate]
   }
 
+  if (
+    (firstUpdate.meta.tc == null && secondUpdate.meta.tc != null) ||
+    (firstUpdate.meta.tc != null && secondUpdate.meta.tc == null)
+  ) {
+    // One update is tracking changes and the other isn't. Tracking changes
+    // results in different behaviour in the history, so we need to keep these
+    // two updates separate.
+    return [firstUpdate, secondUpdate]
+  }
+
+  if (Boolean(firstUpdate.op.u) !== Boolean(secondUpdate.op.u)) {
+    // One update is an undo and the other isn't. If we were to merge the two
+    // updates, we would have to choose one value for the flag, which would be
+    // partially incorrect. Moreover, a tracked delete that is also an undo is
+    // treated as a tracked insert rejection by the history, so these updates
+    // need to be well separated.
+    return [firstUpdate, secondUpdate]
+  }
+
+  if (
+    firstUpdate.op.trackedDeleteRejection ||
+    secondUpdate.op.trackedDeleteRejection
+  ) {
+    // Do not merge tracked delete rejections. Each tracked delete rejection is
+    // a separate operation.
+    return [firstUpdate, secondUpdate]
+  }
+
+  if (
+    firstUpdate.op.trackedChanges != null ||
+    secondUpdate.op.trackedChanges != null
+  ) {
+    // Do not merge ops that span tracked changes.
+    // TODO: This could theoretically be handled, but it would be complex. One
+    // would need to take tracked deletes into account when merging inserts and
+    // deletes together.
+    return [firstUpdate, secondUpdate]
+  }
+
   const firstOp = firstUpdate.op
   const secondOp = secondUpdate.op
   const firstSize =
@@ -206,26 +302,38 @@ function _concatTwoUpdates(firstUpdate, secondUpdate) {
   ) {
     return [
       mergeUpdatesWithOp(firstUpdate, secondUpdate, {
-        p: firstOp.p,
+        ...firstOp,
         i: strInject(firstOp.i, secondOp.p - firstOp.p, secondOp.i),
       }),
     ]
-    // Two deletes
-  } else if (
+  }
+
+  // Two deletes
+  if (
     firstOp.d != null &&
     secondOp.d != null &&
     firstOpInsideSecondOp &&
-    combinedLengthUnderLimit
+    combinedLengthUnderLimit &&
+    firstUpdate.meta.tc == null &&
+    secondUpdate.meta.tc == null
   ) {
     return [
       mergeUpdatesWithOp(firstUpdate, secondUpdate, {
-        p: secondOp.p,
+        ...secondOp,
         d: strInject(secondOp.d, firstOp.p - secondOp.p, firstOp.d),
       }),
     ]
-    // An insert and then a delete
-  } else if (firstOp.i != null && secondOp.d != null && secondOpInsideFirstOp) {
-    offset = secondOp.p - firstOp.p
+  }
+
+  // An insert and then a delete
+  if (
+    firstOp.i != null &&
+    secondOp.d != null &&
+    secondOpInsideFirstOp &&
+    firstUpdate.meta.tc == null &&
+    secondUpdate.meta.tc == null
+  ) {
+    const offset = secondOp.p - firstOp.p
     const insertedText = firstOp.i.slice(offset, offset + secondOp.d.length)
     // Only trim the insert when the delete is fully contained within in it
     if (insertedText === secondOp.d) {
@@ -235,7 +343,7 @@ function _concatTwoUpdates(firstUpdate, secondUpdate) {
       } else {
         return [
           mergeUpdatesWithOp(firstUpdate, secondUpdate, {
-            p: firstOp.p,
+            ...firstOp,
             i: insert,
           }),
         ]
@@ -244,35 +352,60 @@ function _concatTwoUpdates(firstUpdate, secondUpdate) {
       // This will only happen if the delete extends outside the insert
       return [firstUpdate, secondUpdate]
     }
+  }
 
-    // A delete then an insert at the same place, likely a copy-paste of a chunk of content
-  } else if (
+  // A delete then an insert at the same place, likely a copy-paste of a chunk of content
+  if (
     firstOp.d != null &&
     secondOp.i != null &&
-    firstOp.p === secondOp.p
+    firstOp.p === secondOp.p &&
+    firstUpdate.meta.tc == null &&
+    secondUpdate.meta.tc == null
   ) {
-    offset = firstOp.p
+    const offset = firstOp.p
+    const hoffset = firstOp.hpos
     const diffUpdates = diffAsShareJsOps(firstOp.d, secondOp.i).map(
       function (op) {
-        op.p += offset
+        // diffAsShareJsOps() returns ops with positions relative to the position
+        // of the copy/paste. We need to adjust these positions so that they
+        // apply to the whole document instead.
+        const pos = op.p
+        op.p = pos + offset
+        if (hoffset != null) {
+          op.hpos = pos + hoffset
+        }
+        if (firstOp.u && secondOp.u) {
+          op.u = true
+        }
         return mergeUpdatesWithOp(firstUpdate, secondUpdate, op)
       }
     )
 
     // Doing a diff like this loses track of the doc lengths for each
     // update, so recalculate them
-    let { doc_length: docLength } = firstUpdate.meta
+    let docLength =
+      firstUpdate.meta.history_doc_length ?? firstUpdate.meta.doc_length
     for (const update of diffUpdates) {
       update.meta.doc_length = docLength
-      docLength = adjustLengthByOp(docLength, update.op)
+      docLength = adjustLengthByOp(docLength, update.op, {
+        tracked: update.meta.tc != null,
+      })
+      delete update.meta.history_doc_length
     }
 
     return diffUpdates
-  } else {
-    return [firstUpdate, secondUpdate]
   }
+
+  return [firstUpdate, secondUpdate]
 }
 
+/**
+ * Return the diff between two strings
+ *
+ * @param {string} before
+ * @param {string} after
+ * @returns {(InsertOp | DeleteOp)[]} the ops that generate that diff
+ */
 export function diffAsShareJsOps(before, after) {
   const diffs = dmp.diff_main(before, after)
   dmp.diff_cleanupSemantic(diffs)

services/project-history/app/js/UpdateTranslator.js

@@ -6,17 +6,19 @@ import * as Errors from './Errors.js'
 import * as OperationsCompressor from './OperationsCompressor.js'
 
 /**
- * @typedef {import('./types.ts').AddDocUpdate} AddDocUpdate
- * @typedef {import('./types.ts').AddFileUpdate} AddFileUpdate
- * @typedef {import('./types.ts').CommentOp} CommentOp
- * @typedef {import('./types.ts').DeleteOp} DeleteOp
- * @typedef {import('./types.ts').InsertOp} InsertOp
- * @typedef {import('./types.ts').Op} Op
- * @typedef {import('./types.ts').RenameUpdate} RenameUpdate
- * @typedef {import('./types.ts').TextUpdate} TextUpdate
- * @typedef {import('./types.ts').DeleteCommentUpdate} DeleteCommentUpdate
- * @typedef {import('./types.ts').Update} Update
- * @typedef {import('./types.ts').UpdateWithBlob} UpdateWithBlob
+ * @typedef {import('./types').AddDocUpdate} AddDocUpdate
+ * @typedef {import('./types').AddFileUpdate} AddFileUpdate
+ * @typedef {import('./types').CommentOp} CommentOp
+ * @typedef {import('./types').DeleteOp} DeleteCommentUpdate
+ * @typedef {import('./types').DeleteOp} DeleteOp
+ * @typedef {import('./types').InsertOp} InsertOp
+ * @typedef {import('./types').Op} Op
+ * @typedef {import('./types').RawScanOp} RawScanOp
+ * @typedef {import('./types').RenameUpdate} RenameUpdate
+ * @typedef {import('./types').TextUpdate} TextUpdate
+ * @typedef {import('./types').TrackingProps} TrackingProps
+ * @typedef {import('./types').Update} Update
+ * @typedef {import('./types').UpdateWithBlob} UpdateWithBlob
  */
 
 /**
@@ -63,15 +65,14 @@ function _convertToChange(projectId, updateWithBlob) {
     ]
     projectVersion = update.version
   } else if (isTextUpdate(update)) {
-    const docLength = update.meta.doc_length
+    const docLength = update.meta.history_doc_length ?? update.meta.doc_length
     let pathname = update.meta.pathname
 
     pathname = _convertPathname(pathname)
     const builder = new OperationsBuilder(docLength, pathname)
     // convert ops
     for (const op of update.op) {
-      // if this throws an exception it will be caught in convertToChanges
-      builder.addOp(op)
+      builder.addOp(op, update)
     }
     operations = builder.finish()
     // add doc version information if present
@@ -232,7 +233,7 @@ class OperationsBuilder {
     /**
      * Currently built text operation
      *
-     * @type {(number | string)[]}
+     * @type {RawScanOp[]}
      */
     this.textOperation = []
 
@@ -247,9 +248,15 @@ class OperationsBuilder {
 
   /**
    * @param {Op} op
+   * @param {Update} update
    * @returns {void}
    */
-  addOp(op) {
+  addOp(op, update) {
+    // We sometimes receive operations that operate at positions outside the
+    // docLength. Document updater coerces the position to the end of the
+    // document. We do the same here.
+    const pos = Math.min(op.hpos ?? op.p, this.docLength)
+
     if (isComment(op)) {
       // Close the current text operation
       this.pushTextOperation()
@@ -260,8 +267,8 @@ class OperationsBuilder {
         commentId: op.t,
         ranges: [
           {
-            pos: op.p,
-            length: op.c.length,
+            pos,
+            length: op.hlen ?? op.c.length,
           },
         ],
       })
@@ -272,11 +279,6 @@ class OperationsBuilder {
       throw new Errors.UnexpectedOpTypeError('unexpected op type', { op })
     }
 
-    // We sometimes receive operations that operate at positions outside the
-    // docLength. Document updater coerces the position to the end of the
-    // document. We do the same here.
-    const pos = Math.min(op.p, this.docLength)
-
     if (pos < this.cursor) {
       this.pushTextOperation()
       // At this point, this.cursor === 0 and we can continue
@@ -287,26 +289,128 @@ class OperationsBuilder {
     }
 
     if (isInsert(op)) {
-      this.insert(op.i)
+      if (op.trackedDeleteRejection) {
+        this.retain(op.i.length, {
+          tracking: {
+            type: 'none',
+            userId: update.meta.user_id,
+            ts: new Date(update.meta.ts).toISOString(),
+          },
+        })
+      } else if (update.meta.tc != null) {
+        this.insert(op.i, {
+          tracking: {
+            type: 'insert',
+            userId: update.meta.user_id,
+            ts: new Date(update.meta.ts).toISOString(),
+          },
+        })
+      } else {
+        this.insert(op.i)
+      }
     }
 
     if (isDelete(op)) {
-      this.delete(op.d.length)
+      const changes = op.trackedChanges ?? []
+
+      // Tracked changes should already be ordered by offset, but let's make
+      // sure they are.
+      changes.sort((a, b) => {
+        const posOrder = a.offset - b.offset
+        if (posOrder !== 0) {
+          return posOrder
+        } else if (a.type === 'insert' && b.type === 'delete') {
+          return 1
+        } else if (a.type === 'delete' && b.type === 'insert') {
+          return -1
+        } else {
+          return 0
+        }
+      })
+
+      let offset = 0
+      for (const change of changes) {
+        if (change.offset > offset) {
+          // Handle the portion before the tracked change
+          if (update.meta.tc != null && op.u == null) {
+            // This is a tracked delete
+            this.retain(change.offset - offset, {
+              tracking: {
+                type: 'delete',
+                userId: update.meta.user_id,
+                ts: new Date(update.meta.ts).toISOString(),
+              },
+            })
+          } else {
+            // This is a regular delete
+            this.delete(change.offset - offset)
+          }
+          offset = change.offset
+        }
+
+        // Now, handle the portion inside the tracked change
+        if (change.type === 'delete') {
+          // Tracked deletes are skipped over when deleting
+          this.retain(change.length)
+        } else if (change.type === 'insert') {
+          // Deletes inside tracked inserts are always regular deletes
+          this.delete(change.length)
+          offset += change.length
+        }
+      }
+      if (offset < op.d.length) {
+        // Handle the portion after the last tracked change
+        if (update.meta.tc != null && op.u == null) {
+          // This is a tracked delete
+          this.retain(op.d.length - offset, {
+            tracking: {
+              type: 'delete',
+              userId: update.meta.user_id,
+              ts: new Date(update.meta.ts).toISOString(),
+            },
+          })
+        } else {
+          // This is a regular delete
+          this.delete(op.d.length - offset)
+        }
+      }
     }
   }
 
-  retain(length) {
-    this.textOperation.push(length)
+  /**
+   * @param {number} length
+   * @param {object} opts
+   * @param {TrackingProps} [opts.tracking]
+   */
+  retain(length, opts = {}) {
+    if (opts.tracking) {
+      this.textOperation.push({ r: length, ...opts })
+    } else {
+      this.textOperation.push(length)
+    }
     this.cursor += length
   }
 
-  insert(str) {
-    this.textOperation.push(str)
+  /**
+   * @param {string} str
+   * @param {object} opts
+   * @param {TrackingProps} [opts.tracking]
+   */
+  insert(str, opts = {}) {
+    if (opts.tracking) {
+      this.textOperation.push({ i: str, ...opts })
+    } else {
+      this.textOperation.push(str)
+    }
     this.cursor += str.length
     this.docLength += str.length
   }
 
-  delete(length) {
+  /**
+   * @param {number} length
+   * @param {object} opts
+   */
+  delete(length, opts = {}) {
     this.textOperation.push(-length)
     this.docLength -= length
   }

services/project-history/app/js/types.ts

@@ -2,10 +2,11 @@ export type Update = TextUpdate | AddDocUpdate | AddFileUpdate | RenameUpdate |
 
 export type UpdateMeta = {
   user_id: string
-  ts: string
+  ts: number
   source?: string
   type?: string
   origin?: RawOrigin
+  tc?: string
 }
 
 export type TextUpdate = {
@@ -15,6 +16,7 @@ export type TextUpdate = {
   meta: UpdateMeta & {
     pathname: string
     doc_length: number
+    history_doc_length?: number
   }
 }
 
@@ -52,17 +54,31 @@ export type Op = InsertOp | DeleteOp | CommentOp
 export type InsertOp = {
   i: string
   p: number
+  u?: boolean
+  hpos?: number
+  trackedDeleteRejection?: boolean
 }
 
 export type DeleteOp = {
   d: string
   p: number
+  u?: boolean
+  hpos?: number
+  trackedChanges?: TrackedChangesInsideDelete[]
+}
+
+export type TrackedChangesInsideDelete = {
+  type: 'insert' | 'delete'
+  offset: number
+  length: number
 }
 
 export type CommentOp = {
   c: string
   p: number
   t: string
+  hpos?: number
+  hlen?: number
 }
 
 export type UpdateWithBlob = {
@@ -73,3 +89,16 @@ export type UpdateWithBlob = {
 export type RawOrigin = {
   kind: string
 }
+
+export type TrackingProps = {
+  type: 'insert' | 'delete' | 'none'
+  userId: string
+  ts: string
+}
+
+export type RawScanOp =
+  | number
+  | string
+  | { r: number; tracking?: TrackingProps }
+  | { i: string; tracking?: TrackingProps; commentIds?: string[] }
+  | { d: number; tracking?: TrackingProps }

services/project-history/test/unit/js/UpdateCompressor/UpdateCompressorTests.js

@@ -148,6 +148,61 @@ describe('UpdateCompressor', function () {
         },
       ])
     })
+
+    it('should take tracked changes into account when calculating the doc length', function () {
+      const meta = {
+        ts: this.ts1,
+        user_id: this.user_id,
+        tc: 'tracked-change-id',
+      }
+      expect(
+        this.UpdateCompressor.convertToSingleOpUpdates([
+          {
+            op: [
+              { p: 6, i: 'orange' }, // doc_length += 6
+              { p: 22, d: 'apple' }, // doc_length doesn't change
+              { p: 12, i: 'melon', u: true }, // doc_length += 5
+              { p: 18, i: 'banana', u: true, trackedDeleteRejection: true }, // doc_length doesn't change
+              { p: 8, d: 'pineapple', u: true }, // doc_length -= 9
+              { p: 11, i: 'fruit salad' },
+            ],
+            meta: { ...meta, doc_length: 20, history_doc_length: 30 },
+            v: 42,
+          },
+        ])
+      ).to.deep.equal([
+        {
+          op: { p: 6, i: 'orange' },
+          meta: { ...meta, doc_length: 30 },
+          v: 42,
+        },
+        {
+          op: { p: 22, d: 'apple' },
+          meta: { ...meta, doc_length: 36 },
+          v: 42,
+        },
+        {
+          op: { p: 12, i: 'melon', u: true },
+          meta: { ...meta, doc_length: 36 },
+          v: 42,
+        },
+        {
+          op: { p: 18, i: 'banana', u: true, trackedDeleteRejection: true },
+          meta: { ...meta, doc_length: 41 },
+          v: 42,
+        },
+        {
+          op: { p: 8, d: 'pineapple', u: true },
+          meta: { ...meta, doc_length: 41 },
+          v: 42,
+        },
+        {
+          op: { p: 11, i: 'fruit salad' },
+          meta: { ...meta, doc_length: 32 },
+          v: 42,
+        },
+      ])
+    })
   })
 
   describe('concatUpdatesWithSameVersion', function () {
@@ -571,6 +626,153 @@ describe('UpdateCompressor', function () {
           },
         ])
       })
+
+      it("should not merge updates that track changes and updates that don't", function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              pathname: 'main.tex',
+              op: { p: 3, i: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              pathname: 'main.tex',
+              op: { p: 6, i: 'bar' },
+              meta: { ts: this.ts2, user_id: this.user_id, tc: 'tracking-id' },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            pathname: 'main.tex',
+            op: { p: 3, i: 'foo' },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 42,
+          },
+          {
+            pathname: 'main.tex',
+            op: { p: 6, i: 'bar' },
+            meta: { ts: this.ts2, user_id: this.user_id, tc: 'tracking-id' },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should not merge undos with regular ops', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              pathname: 'main.tex',
+              op: { p: 3, i: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              pathname: 'main.tex',
+              op: { p: 6, i: 'bar', u: true },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            pathname: 'main.tex',
+            op: { p: 3, i: 'foo' },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 42,
+          },
+          {
+            pathname: 'main.tex',
+            op: { p: 6, i: 'bar', u: true },
+            meta: { ts: this.ts2, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should not merge tracked delete rejections', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              pathname: 'main.tex',
+              op: { p: 3, i: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              pathname: 'main.tex',
+              op: { p: 6, i: 'bar', trackedDeleteRejection: true },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            pathname: 'main.tex',
+            op: { p: 3, i: 'foo' },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 42,
+          },
+          {
+            pathname: 'main.tex',
+            op: { p: 6, i: 'bar', trackedDeleteRejection: true },
+            meta: { ts: this.ts2, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should preserve history metadata', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, i: 'foo', hpos: 13 },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              op: { p: 6, i: 'bar', hpos: 16 },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, i: 'foobar', hpos: 13 },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should not merge updates from different users', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, i: 'foo', hpos: 13 },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              op: { p: 6, i: 'bar', hpos: 16 },
+              meta: { ts: this.ts2, user_id: this.other_user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, i: 'foo', hpos: 13 },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 42,
+          },
+          {
+            op: { p: 6, i: 'bar', hpos: 16 },
+            meta: { ts: this.ts2, user_id: this.other_user_id },
+            v: 43,
+          },
+        ])
+      })
     })
 
     describe('delete - delete', function () {
@@ -647,6 +849,95 @@ describe('UpdateCompressor', function () {
           },
         ])
       })
+
+      it('should not merge deletes over tracked changes', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, d: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              op: {
+                p: 3,
+                d: 'bar',
+                trackedChanges: [{ type: 'delete', pos: 2, length: 10 }],
+              },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, d: 'foo' },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 42,
+          },
+          {
+            op: {
+              p: 3,
+              d: 'bar',
+              trackedChanges: [{ type: 'delete', pos: 2, length: 10 }],
+            },
+            meta: { ts: this.ts2, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should preserve history metadata', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, d: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              op: { p: 3, d: 'bar' },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, d: 'foobar' },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should not merge when the deletes are tracked', function () {
+        // TODO: We should be able to lift that constraint, but it would
+        // require recalculating the hpos on the second op.
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, d: 'foo' },
+              meta: { ts: this.ts1, user_id: this.user_id, tc: 'tracking-id' },
+              v: 42,
+            },
+            {
+              op: { p: 3, d: 'bar' },
+              meta: { ts: this.ts2, user_id: this.user_id, tc: 'tracking-id' },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, d: 'foo' },
+            meta: { ts: this.ts1, user_id: this.user_id, tc: 'tracking-id' },
+            v: 42,
+          },
+          {
+            op: { p: 3, d: 'bar' },
+            meta: { ts: this.ts2, user_id: this.user_id, tc: 'tracking-id' },
+            v: 43,
+          },
+        ])
+      })
     })
 
     describe('insert - delete', function () {
@@ -768,6 +1059,29 @@ describe('UpdateCompressor', function () {
           },
         ])
       })
+
+      it('should preserver history metadata', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, i: 'foo', hpos: 13 },
+              meta: { ts: this.ts1, user_id: this.user_id },
+              v: 42,
+            },
+            {
+              op: { p: 5, d: 'o', hpos: 15 },
+              meta: { ts: this.ts2, user_id: this.user_id },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, i: 'fo', hpos: 13 },
+            meta: { ts: this.ts1, user_id: this.user_id },
+            v: 43,
+          },
+        ])
+      })
     })
 
     describe('delete - insert', function () {
@@ -815,6 +1129,90 @@ describe('UpdateCompressor', function () {
           ])
         ).to.deep.equal([])
       })
+
+      it('should preserver history metadata', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: {
+                p: 3,
+                d: 'one two three four five six seven eight',
+                hpos: 13,
+              },
+              meta: { ts: this.ts1, user_id: this.user_id, doc_length: 100 },
+              v: 42,
+            },
+            {
+              op: {
+                p: 3,
+                i: 'one 2 three four five six seven eight',
+                hpos: 13,
+              },
+              meta: { ts: this.ts2, user_id: this.user_id, doc_length: 100 },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 7, d: 'two', hpos: 17 },
+            meta: { ts: this.ts1, user_id: this.user_id, doc_length: 100 },
+            v: 43,
+          },
+          {
+            op: { p: 7, i: '2', hpos: 17 },
+            meta: { ts: this.ts1, user_id: this.user_id, doc_length: 97 },
+            v: 43,
+          },
+        ])
+      })
+
+      it('should not merge when tracking changes', function () {
+        expect(
+          this.UpdateCompressor.compressUpdates([
+            {
+              op: { p: 3, d: 'one two three four five six seven eight' },
+              meta: {
+                ts: this.ts1,
+                user_id: this.user_id,
+                doc_length: 100,
+                tc: 'tracking-id',
+              },
+              v: 42,
+            },
+            {
+              op: { p: 3, i: 'one 2 three four five six seven eight' },
+              meta: {
+                ts: this.ts2,
+                user_id: this.user_id,
+                doc_length: 100,
+                tc: 'tracking-id',
+              },
+              v: 43,
+            },
+          ])
+        ).to.deep.equal([
+          {
+            op: { p: 3, d: 'one two three four five six seven eight' },
+            meta: {
+              ts: this.ts1,
+              user_id: this.user_id,
+              doc_length: 100,
+              tc: 'tracking-id',
+            },
+            v: 42,
+          },
+          {
+            op: { p: 3, i: 'one 2 three four five six seven eight' },
+            meta: {
+              ts: this.ts2,
+              user_id: this.user_id,
+              doc_length: 100,
+              tc: 'tracking-id',
+            },
+            v: 43,
+          },
+        ])
+      })
     })
 
     describe('a long chain of ops', function () {

services/project-history/test/unit/js/UpdateTranslator/UpdateTranslatorTests.js

@@ -831,5 +831,276 @@ describe('UpdateTranslator', function () {
         }).to.throw('unexpected op type')
       })
     })
+
+    describe('text updates with history metadata', function () {
+      it('handles deletes over tracked deletes', function () {
+        const updates = [
+          {
+            update: {
+              doc: this.doc_id,
+              op: [
+                { i: 'foo', p: 3, hpos: 5 },
+                {
+                  d: 'quux',
+                  p: 10,
+                  hpos: 15,
+                  trackedChanges: [
+                    { type: 'delete', offset: 2, length: 3 },
+                    { type: 'delete', offset: 3, length: 1 },
+                  ],
+                },
+                { c: 'noteworthy', p: 8, t: 'comment-id', hpos: 11, hlen: 14 },
+              ],
+              v: this.version,
+              meta: {
+                user_id: this.user_id,
+                ts: new Date(this.timestamp).getTime(),
+                pathname: '/main.tex',
+                doc_length: 20,
+                history_doc_length: 30,
+                source: 'some-editor-id',
+              },
+            },
+          },
+        ]
+
+        const changes = this.UpdateTranslator.convertToChanges(
+          this.project_id,
+          updates
+        ).map(change => change.toRaw())
+
+        expect(changes).to.deep.equal([
+          {
+            authors: [],
+            operations: [
+              {
+                pathname: 'main.tex',
+                textOperation: [5, 'foo', 7, -2, 3, -1, 1, -1, 10],
+              },
+              {
+                pathname: 'main.tex',
+                commentId: 'comment-id',
+                ranges: [{ pos: 11, length: 14 }],
+                resolved: false,
+              },
+            ],
+            v2Authors: [this.user_id],
+            timestamp: this.timestamp,
+            v2DocVersions: {
+              '59bfd450e3028c4d40a1e9ab': {
+                pathname: 'main.tex',
+                v: 0,
+              },
+            },
+          },
+        ])
+      })
+
+      it('handles tracked delete rejections specially', function () {
+        const updates = [
+          {
+            update: {
+              doc: this.doc_id,
+              op: [{ i: 'foo', p: 3, trackedDeleteRejection: true }],
+              v: this.version,
+              meta: {
+                user_id: this.user_id,
+                ts: new Date(this.timestamp).getTime(),
+                pathname: '/main.tex',
+                doc_length: 20,
+                source: 'some-editor-id',
+              },
+            },
+          },
+        ]
+
+        const changes = this.UpdateTranslator.convertToChanges(
+          this.project_id,
+          updates
+        ).map(change => change.toRaw())
+
+        expect(changes).to.deep.equal([
+          {
+            authors: [],
+            operations: [
+              {
+                pathname: 'main.tex',
+                textOperation: [
+                  3,
+                  {
+                    r: 3,
+                    tracking: {
+                      type: 'none',
+                      userId: this.user_id,
+                      ts: new Date(this.timestamp).toISOString(),
+                    },
+                  },
+                  14,
+                ],
+              },
+            ],
+            v2Authors: [this.user_id],
+            timestamp: this.timestamp,
+            v2DocVersions: {
+              '59bfd450e3028c4d40a1e9ab': {
+                pathname: 'main.tex',
+                v: 0,
+              },
+            },
+          },
+        ])
+      })
+
+      it('handles tracked changes', function () {
+        const updates = [
+          {
+            update: {
+              doc: this.doc_id,
+              op: [
+                { i: 'inserted', p: 5 },
+                { d: 'deleted', p: 20 },
+                { i: 'rejected deletion', p: 30, trackedDeleteRejection: true },
+                { d: 'rejected insertion', p: 50, u: true },
+              ],
+              v: this.version,
+              meta: {
+                tc: 'tracked-change-id',
+                user_id: this.user_id,
+                ts: new Date(this.timestamp).getTime(),
+                pathname: '/main.tex',
+                doc_length: 70,
+                source: 'some-editor-id',
+              },
+            },
+          },
+        ]
+
+        const changes = this.UpdateTranslator.convertToChanges(
+          this.project_id,
+          updates
+        ).map(change => change.toRaw())
+
+        expect(changes).to.deep.equal([
+          {
+            authors: [],
+            operations: [
+              {
+                pathname: 'main.tex',
+                textOperation: [
+                  5,
+                  {
+                    i: 'inserted',
+                    tracking: {
+                      type: 'insert',
+                      userId: this.user_id,
+                      ts: new Date(this.timestamp).toISOString(),
+                    },
+                  },
+                  7,
+                  {
+                    r: 7,
+                    tracking: {
+                      type: 'delete',
+                      userId: this.user_id,
+                      ts: new Date(this.timestamp).toISOString(),
+                    },
+                  },
+                  3,
+                  {
+                    r: 17,
+                    tracking: {
+                      type: 'none',
+                      userId: this.user_id,
+                      ts: new Date(this.timestamp).toISOString(),
+                    },
+                  },
+                  3,
+                  -18,
+                  10,
+                ],
+              },
+            ],
+            v2Authors: [this.user_id],
+            timestamp: this.timestamp,
+            v2DocVersions: {
+              '59bfd450e3028c4d40a1e9ab': {
+                pathname: 'main.tex',
+                v: 0,
+              },
+            },
+          },
+        ])
+      })
+
+      it('handles a delete over a mix of tracked inserts and tracked deletes', function () {
+        const updates = [
+          {
+            update: {
+              doc: this.doc_id,
+              op: [
+                {
+                  d: 'abcdef',
+                  p: 10,
+                  trackedChanges: [
+                    { type: 'insert', offset: 0, length: 3 },
+                    { type: 'delete', offset: 2, length: 10 },
+                    { type: 'insert', offset: 2, length: 2 },
+                  ],
+                },
+              ],
+              v: this.version,
+              meta: {
+                tc: 'tracking-id',
+                user_id: this.user_id,
+                ts: new Date(this.timestamp).getTime(),
+                pathname: '/main.tex',
+                doc_length: 20,
+                history_doc_length: 30,
+                source: 'some-editor-id',
+              },
+            },
+          },
+        ]
+
+        const changes = this.UpdateTranslator.convertToChanges(
+          this.project_id,
+          updates
+        ).map(change => change.toRaw())
+
+        expect(changes).to.deep.equal([
+          {
+            authors: [],
+            operations: [
+              {
+                pathname: 'main.tex',
+                textOperation: [
+                  10,
+                  -3,
+                  10,
+                  -2,
+                  {
+                    r: 1,
+                    tracking: {
+                      type: 'delete',
+                      userId: this.user_id,
+                      ts: this.timestamp,
+                    },
+                  },
+                  4,
+                ],
+              },
+            ],
+            v2Authors: [this.user_id],
+            timestamp: this.timestamp,
+            v2DocVersions: {
+              '59bfd450e3028c4d40a1e9ab': {
+                pathname: 'main.tex',
+                v: 0,
+              },
+            },
+          },
+        ])
+      })
+    })
   })
 })