GitHub · Pull requests · REST API · Checked October 25, 2026

GitHub: why the pull request was not created

A pull request is created with POST /repos/OWNER/REPO/pulls: title, head (the branch with your changes; from a fork in the same network, USER:BRANCH), base (an existing branch of this repository), and if you like body, draft and maintainer_can_modify. GitHub's documentation names the statuses: 201 when it is created, 403, and 422 when the request fails validation or the endpoint has been spammed. It does not list the 422 messages; the ones below are quoted from public reports, with GitHub's documented rules behind them (checked October 25, 2026).

HTTP/1.1 422 Unprocessable Entity

{"message": "Validation Failed", "errors": [{"resource": "PullRequest", "code": "custom", "message": "No commits between main and my-branch"}], "documentation_url": "https://docs.github.com/rest/pulls/pulls#create-a-pull-request", "status": "422"}

422: what GitHub says, and why

A pull request already exists for OWNER:BRANCH. (code custom): an open pull request from this head branch is already there.
No commits between BASE and HEAD (code custom): the head branch has no commit that the base branch does not have. The new commits are not pushed yet, the branch was already merged, or head and base name the wrong branches.
{"resource":"PullRequest","field":"head","code":"invalid"}: GitHub does not find head: the branch is not on GitHub yet, its name is spelled differently, or it is in a fork and was sent without USER:. GitHub's documentation says that a pull request between two repositories owned by the same organization also needs head_repo.
{"resource":"PullRequest","field":"base","code":"invalid"}: base is not a branch of this repository. GitHub's documentation says it should be an existing branch of the repository, and that a pull request cannot ask to merge into a branch of another repository.
Draft pull requests are not supported in this repository.: GitHub's documentation says drafts are available in public repositories with GitHub Free, GitHub Free for organizations, GitHub Pro and legacy per-repository plans, and in public and private repositories with GitHub Team and GitHub Enterprise Cloud. A draft in a private repository on GitHub Free or GitHub Pro is refused.

403, 404

403 GitHub Actions is not permitted to create or approve pull requests.: the token is a workflow's GITHUB_TOKEN, and the repository does not allow Actions to create and approve pull requests (see why GitHub refused the review, where the same setting refuses approvals).
403 Resource not accessible by personal access token (or by integration): GitHub's list of permissions gives this endpoint to Pull requests with write access, for a fine-grained token (see which permission to add).
Who may open one: GitHub's documentation says that to open a pull request in a public repository you need write access to the head branch, and that in a repository owned by an organization you must be a member of that organization. A repository can also turn pull requests off, let only collaborators create them, or limit them for people without write access (see pull requests turned off or limited).
Too fast: GitHub's documentation says that creating content too quickly with this endpoint may hit a secondary rate limit, answered with 403 or 429 (see "API rate limit exceeded").
404: the repository is not there for this token, which is also how GitHub answers a private repository the token cannot see.

What to do

Already exists: find it with GET /repos/OWNER/REPO/pulls?head=OWNER:BRANCH&state=open; pushing to the branch updates that pull request.
No commits between: push the new commits first, or check that base is the branch you mean to merge into.
head invalid: push the branch (git push -u origin BRANCH); from a fork, send USER:BRANCH, and head_repo when both repositories belong to one organization.
base invalid: the name of an existing branch of this repository.
Drafts not supported: create it without draft, ready for review.
GitHub Actions: in the repository's Settings, Actions, General, Workflow permissions, allow GitHub Actions to create and approve pull requests (in an organization, its owner may have to allow it first), or use another token.

In IntelliJ IDEA: "No changes between" and "Pull request already exists"

How the GitHub support built into IntelliJ IDEA creates a pull request, in its source (checked October 30, 2026; IntelliJ IDEA: GHPRCreateViewModel.kt, GHPRCreateComponentFactory.kt, GHPRCreationServiceImpl.kt, createPullRequest.graphql, GHAPIExceptionUtil.kt):

Before anything is sent, it checks the two branches ("Checking pull request branches"), and Create Pull Request stays off until the check passes. "No changes between 'BASE' and 'HEAD'" comes when your local branch tracks the base branch itself, as a branch made from origin/main with tracking does, whatever commits it has; or when your local repository finds no commit in BASE..HEAD, against the base branch as it was last fetched. For the first, push the branch to a branch of its own (git push -u origin BRANCH).
"Pull request already exists", with View to open it: when the head branch is on GitHub (a remote branch, or a local branch that tracks one), it asks GitHub for an open pull request with that base and head (GET /repos/OWNER/REPO/pulls?state=open&base=BASE&head=OWNER:BRANCH). A local branch that tracks nothing is not looked up.
A local branch is pushed first when the commit on GitHub differs ("Pushing a pull request branch"); one with nothing to push to asks for a "Remote branch name:". So the head GitHub receives is already there, not one it would find invalid. If the push fails, GitHub is not asked, and the reason is under Details.
It creates the pull request with GitHub's GraphQL API (the createPullRequest mutation), not the REST endpoint above: base and head by branch name, with OWNER: before a head from another repository; an empty title becomes the branch name. Create Draft Pull Request is offered beside it without a check on whether the repository allows drafts.
When GitHub refuses, it reads "Failed to create a pull request", and Details shows GitHub's message for the error GraphQL returns; a token without the scopes it needs reads "User authorization failed" instead.
Reviewers, assignees and labels are added after it is created ("Updating pull request fields"). If that step fails, the pull request is already on GitHub, though it reads the same "Failed to create a pull request"; look for it before pressing Create again.

GitHub pull requests in IntelliJ IDEA

Pull Request Inbox for GitHub, a plugin by Lesstep for JetBrains IDEs 2024.1 or later, creates a pull request from the branch you have checked out, into a target branch it offers from the repository's branches on GitHub as you type; a name that is not among them, or the same branch, is refused before anything is sent. When the branch is not on GitHub yet, it says so and opens the IDE's push dialog, instead of sending a head that GitHub would find invalid. When a pull request for the branch is already open, it says so, with GitHub's words; for other refusals it shows GitHub's words. A created pull request comes with a link to open it in the browser. 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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