fix: remove repository file from state when its commit no longer exists

github/resource_github_repository_file.go

@@ -2,6 +2,7 @@ package github
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -331,6 +332,19 @@ func resourceGithubRepositoryFileRead(ctx context.Context, d *schema.ResourceDat
 		commit, err = getFileCommit(ctx, client, owner, repoName, file, ref)
 	}
 	if err != nil {
+		// The commit recorded in state, or any commit still containing the file,
+		// may be unreachable because the repository, branch or history is gone.
+		// That is "the resource no longer exists", not a failure to read it.
+		if ghErr, ok := errors.AsType[*github.ErrorResponse](err); ok && ghErr.Response != nil && ghErr.Response.StatusCode == http.StatusNotFound {
+			tflog.Info(ctx, "Removing repository file from state because its commit no longer exists in GitHub")
+			d.SetId("")
+			return nil
+		}
+		if errors.Is(err, errFileCommitNotFound) {
+			tflog.Info(ctx, "Removing repository file from state because no commit contains it")
+			d.SetId("")
+			return nil
+		}
 		return diag.FromErr(err)
 	}
 	tflog.Debug(ctx, "Found file in commit", map[string]any{

github/util_repo.go

@@ -33,6 +33,11 @@ func checkRepositoryBranchExists(ctx context.Context, client *github.Client, own
 	return nil
 }
 
+// errFileCommitNotFound reports that no commit reachable from the requested ref
+// still contains the file, so callers can remove the resource from state rather
+// than surfacing a hard error.
+var errFileCommitNotFound = errors.New("no commit contains the file")
+
 func getFileCommit(ctx context.Context, client *github.Client, owner, repo, file, branch string) (*github.RepositoryCommit, error) {
 	opts := &github.CommitsListOptions{
 		SHA:  branch,
@@ -89,7 +94,7 @@ func getFileCommit(ctx context.Context, client *github.Client, owner, repo, file
 		}
 	}
 
-	return nil, fmt.Errorf("cannot find file %s in repo %s/%s", file, owner, repo)
+	return nil, fmt.Errorf("cannot find file %s in repo %s/%s: %w", file, owner, repo, errFileCommitNotFound)
 }
 
 // getAutolinkByKeyPrefix returns a single autolink reference by key prefix that was configured for the given repository.

github/util_repo_test.go

@@ -0,0 +1,34 @@
+package github
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// Test_getFileCommit_NoCommitContainsFile locks in the errFileCommitNotFound
+// sentinel. resourceGithubRepositoryFileRead relies on it to remove the resource
+// from state instead of returning a hard error, so unwrapping this error would
+// silently reintroduce that failure.
+func Test_getFileCommit_NoCommitContainsFile(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
+		if _, err := w.Write([]byte("[]")); err != nil {
+			t.Errorf("failed to write response: %s", err)
+		}
+	}))
+	defer ts.Close()
+
+	client := mustCreateTestGitHubClient(t, ts.URL+"/")
+
+	_, err := getFileCommit(context.Background(), client, "owner", "repo", "some/file.txt", "main")
+	if err == nil {
+		t.Fatal("expected an error when no commit contains the file, got nil")
+	}
+
+	if !errors.Is(err, errFileCommitNotFound) {
+		t.Errorf("errors.Is(err, errFileCommitNotFound) = false, want true; got error: %s", err)
+	}
+}