GitHub · Pull requests · REST and GraphQL API · Checked October 26, 2026

GitHub: why a line comment is outdated, or not on the diff

A comment on lines of a pull request is made on a commit (commit_id) and on lines of a file at that commit. GitHub's documentation for creating one says that a comment not made on the latest commit may become outdated when a later commit changes its line, and the GraphQL API marks such a review thread with isOutdated: "outdated by newer changes". The comment is not lost; GitHub keeps the commit and the lines it was made on (checked October 26, 2026).

query {
  repository(owner: "OWNER", name: "REPO") {
    pullRequest(number: NUMBER) {
      reviewThreads(first: 100) {
        nodes { path isOutdated isResolved line originalLine diffSide subjectType }
      }
    }
  }
}

What GitHub keeps

REST (GET /repos/OWNER/REPO/pulls/NUMBER/comments): each comment has commit_id and original_commit_id, line and original_line (for a range also start_line and original_start_line), and side. The original_ fields are the commit and the lines the comment was made on; diff_hunk is the diff around the line as it was. position and original_position, places in the diff rather than lines of the file, are closing down in favor of line and original_line.
GraphQL (PullRequestReviewThread): isOutdated, line (the line in the file the thread refers to) and originalLine, diffSide, and subjectType, a line or a whole file. Each comment (PullRequestReviewComment) has outdated, commit and originalCommit.
Lines of the file, not of the diff: an original line number counts in the file at the original commit. In today's file the same number may hold other code, or be past the end.

Where outdated conversations show

On github.com: the Conversations menu on the Files changed tab shows which conversations are unresolved, resolved, and outdated (GitHub's documentation on commenting on a pull request).
Outdated is not resolved: they are two separate marks (isOutdated and isResolved in GraphQL). A resolved conversation collapses. Resolving takes having opened the pull request or write access to the repository (see why a conversation was not resolved).

Not on today's diff

Its lines changed: the comment is outdated, and its place is the original line at the original commit.
The file is no longer among the changed files: when later commits undo a file's changes, the file drops out of the pull request's diff. The comment keeps its path.
A comment on the whole file (subject_type file) has no line to show at.
Deleted: reading a deleted comment answers 404 (deleting answers 204), and so does a reply to a thread whose first comment was deleted (see why a comment or reply was refused).

What to do

See the code it was about: the file at original_commit_id (GET /repos/OWNER/REPO/contents/PATH?ref=SHA, or that commit on github.com), line original_line; diff_hunk shows the lines around it as they were.
Comment on today's code: a new comment with the head commit as commit_id and lines of today's diff (see why a comment on lines was refused).
Done with it: when a later commit dealt with it, resolve the conversation.

In IntelliJ IDEA: the OUTDATED tag is GitHub's, and the IDE follows the old line through the commits

How the GitHub support built into IntelliJ IDEA handles an outdated review thread, in its source (checked October 31, 2026; IntelliJ IDEA: pullRequestReviewThread.graphql, GHPullRequestReviewThread.kt, GHPRTimelineThreadViewModel.kt, GHPRTimelineThreadComponentFactory.kt, GHPRThreadsViewModels.kt, CollaborationToolsBundle.properties):

What it reads: for each thread, GitHub's isOutdated, line and originalLine (with startLine and originalStartLine for a range), and from the first comment its commit and originalCommit.
In the timeline, the thread carries an OUTDATED tag exactly when GitHub returns isOutdated as true. Its code is the diff hunk GitHub saved with the thread, marked at the line it was written on (originalLine). When GitHub returns an empty hunk, which the source notes for file-level comments and some outdated threads, no code is drawn for it.
In the diff and the editor, it looks for the thread's place in today's changes: with GitHub's current line on commit when there is one, otherwise by following originalLine on originalCommit through the pull request's commits. When the file of that commit is not among the pull request's changes, or the line cannot be followed, the thread gets no place there.

GitHub pull requests in IntelliJ IDEA

Pull Request Inbox for GitHub, a plugin by Lesstep for JetBrains IDEs 2024.1 or later, reads each line comment's line, and for a comment GitHub gives without a current line, original_line and original_commit_id. On the Comments tab such a thread names the earlier commit next to its file and line ("the lines have changed since"); in the file's diff its marker stays at the line number it had then, and its tooltip says the comment was made at an earlier commit and that the line may now hold other code. A comment on a whole file is not called outdated. Resolved threads say who resolved them. Going to a comment whose file is no longer among the changed files says so. The review inbox, diffs and conversations are free; approving, commenting and merging are Pro (US$1.50 a month, with a 30-day trial).

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