Add conflict_resolution input

action.yml

@@ -44,9 +44,18 @@ inputs:
       - For "Merged as a merge commit", the action cherry-picks the commits from the pull request.
 
       By default, the action always cherry-picks the commits from the pull request.
+
+      #### `backport_on_conflicts`
+
+      When enabled, the action will create the pull request even if conflict are detected during the cherry-pick.
+      The first conflict encountered will be committed and the remaining of the cherry-pick will need to be done by the users.
+      Instructions are provided on the original pull request on how to resolve the conflict and continue the cherry-pick.
+
+      By default, the action fails on the first conflict encountered and the pull request is not created.
     default: >
       {
-        "detect_merge_method": false
+        "detect_merge_method": false,
+        "backport_on_conflicts": false
       }
   github_token:
     description: >
@@ -112,5 +121,5 @@ runs:
   using: "node20"
   main: "dist/index.js"
 branding:
-  icon: 'copy'
-  color: 'yellow'
+  icon: "copy"
+  color: "yellow"

dist/index.js

@@ -50,6 +50,7 @@ const git_1 = __nccwpck_require__(3374);
 const utils = __importStar(__nccwpck_require__(918));
 const experimentalDefaults = {
     detect_merge_method: false,
+    backport_on_conflicts: false,
 };
 exports.experimentalDefaults = experimentalDefaults;
 var Output;
@@ -204,8 +205,9 @@ class Backport {
                             });
                             continue;
                         }
+                        let uncommitedShas;
                         try {
-                            yield this.git.cherryPick(commitShasToCherryPick, this.config.pwd);
+                            uncommitedShas = yield this.git.cherryPick(commitShasToCherryPick, this.config.experimental.backport_on_conflicts, this.config.pwd);
                         }
                         catch (error) {
                             const message = this.composeMessageForCherryPickFailure(target, branchname, commitShasToCherryPick);
@@ -243,6 +245,7 @@ class Backport {
                             head: branchname,
                             base: target,
                             maintainer_can_modify: true,
+                            draft: uncommitedShas !== null,
                         });
                         if (new_pr_response.status != 201) {
                             console.error(JSON.stringify(new_pr_response));
@@ -295,15 +298,30 @@ class Backport {
                                 // The PR was still created so let's still comment on the original.
                             }
                         }
-                        const message = this.composeMessageForSuccess(new_pr.number, target);
-                        successByTarget.set(target, true);
-                        createdPullRequestNumbers.push(new_pr.number);
-                        yield this.github.createComment({
-                            owner,
-                            repo,
-                            issue_number: pull_number,
-                            body: message,
-                        });
+                        // post success message to original pr
+                        {
+                            const message = uncommitedShas !== null
+                                ? this.composeMessageForSuccessWithConflicts(new_pr.number, target, branchname, uncommitedShas)
+                                : this.composeMessageForSuccess(new_pr.number, target);
+                            successByTarget.set(target, true);
+                            createdPullRequestNumbers.push(new_pr.number);
+                            yield this.github.createComment({
+                                owner,
+                                repo,
+                                issue_number: pull_number,
+                                body: message,
+                            });
+                        }
+                        // post message to new pr to resolve conflict
+                        if (uncommitedShas !== null) {
+                            const message = this.composeMessageToResolveConflicts(target, branchname, uncommitedShas, true);
+                            yield this.github.createComment({
+                                owner,
+                                repo,
+                                issue_number: new_pr.number,
+                                body: message,
+                            });
+                        }
                     }
                     catch (error) {
                         if (error instanceof Error) {
@@ -350,22 +368,34 @@ class Backport {
     }
     composeMessageForCheckoutFailure(target, branchname, commitShasToCherryPick) {
         const reason = "because it was unable to create a new branch";
-        const suggestion = this.composeSuggestion(target, branchname, commitShasToCherryPick);
+        const suggestion = this.composeSuggestion(target, branchname, commitShasToCherryPick, false);
         return (0, dedent_1.default) `Backport failed for \`${target}\`, ${reason}.
 
                   Please cherry-pick the changes locally.
                   ${suggestion}`;
     }
     composeMessageForCherryPickFailure(target, branchname, commitShasToCherryPick) {
         const reason = "because it was unable to cherry-pick the commit(s)";
-        const suggestion = this.composeSuggestion(target, branchname, commitShasToCherryPick);
+        const suggestionToResolve = this.composeMessageToResolveConflicts(target, branchname, commitShasToCherryPick, false);
         return (0, dedent_1.default) `Backport failed for \`${target}\`, ${reason}.
 
-                  Please cherry-pick the changes locally and resolve any conflicts.
+                  ${suggestionToResolve}`;
+    }
+    composeMessageToResolveConflicts(target, branchname, commitShasToCherryPick, branchExist) {
+        const suggestion = this.composeSuggestion(target, branchname, commitShasToCherryPick, branchExist);
+        return (0, dedent_1.default) `Please cherry-pick the changes locally and resolve any conflicts.
                   ${suggestion}`;
     }
-    composeSuggestion(target, branchname, commitShasToCherryPick) {
-        return (0, dedent_1.default) `\`\`\`bash
+    composeSuggestion(target, branchname, commitShasToCherryPick, branchExist) {
+        return branchExist
+            ? (0, dedent_1.default) `\`\`\`bash
+      git fetch origin ${target}
+      git worktree add -d .worktree/${branchname} origin/${target}
+      cd .worktree/${branchname}
+      git switch ${branchname}
+      git cherry-pick -x ${commitShasToCherryPick.join(" ")}
+      \`\`\``
+            : (0, dedent_1.default) `\`\`\`bash
       git fetch origin ${target}
       git worktree add -d .worktree/${branchname} origin/${target}
       cd .worktree/${branchname}
@@ -387,6 +417,13 @@ class Backport {
         return (0, dedent_1.default) `Successfully created backport PR for \`${target}\`:
                   - #${pr_number}`;
     }
+    composeMessageForSuccessWithConflicts(pr_number, target, branchname, commitShasToCherryPick) {
+        const suggestionToResolve = this.composeMessageToResolveConflicts(target, branchname, commitShasToCherryPick, true);
+        return (0, dedent_1.default) `Created backport PR for \`${target}\`:
+                  - #${pr_number} with remaining conflicts!
+
+                  ${suggestionToResolve}`;
+    }
     createOutput(successByTarget, createdPullRequestNumbers) {
         const anyTargetFailed = Array.from(successByTarget.values()).includes(false);
         core.setOutput(Output.wasSuccessful, !anyTargetFailed);
@@ -542,12 +579,40 @@ class Git {
             }
         });
     }
-    cherryPick(commitShas, pwd) {
+    cherryPick(commitShas, allowPartialCherryPick, pwd) {
         return __awaiter(this, void 0, void 0, function* () {
-            const { exitCode } = yield this.git("cherry-pick", ["-x", ...commitShas], pwd);
-            if (exitCode !== 0) {
+            const abortCherryPickAndThrow = (commitShas, exitCode) => __awaiter(this, void 0, void 0, function* () {
                 yield this.git("cherry-pick", ["--abort"], pwd);
                 throw new Error(`'git cherry-pick -x ${commitShas}' failed with exit code ${exitCode}`);
+            });
+            if (!allowPartialCherryPick) {
+                const { exitCode } = yield this.git("cherry-pick", ["-x", ...commitShas], pwd);
+                if (exitCode !== 0) {
+                    yield abortCherryPickAndThrow(commitShas, exitCode);
+                }
+                return null;
+            }
+            else {
+                let uncommitedShas = [...commitShas];
+                // Cherry-pick commit one by one.
+                for (const sha of commitShas) {
+                    const { exitCode } = yield this.git("cherry-pick", ["-x", sha], pwd);
+                    if (exitCode !== 0) {
+                        if (exitCode === 1) {
+                            // conflict encountered
+                            // abort conflict cherry-pick
+                            yield this.git("cherry-pick", ["--abort"], pwd);
+                            return uncommitedShas;
+                        }
+                        else {
+                            // other fail reasons
+                            yield abortCherryPickAndThrow([sha], exitCode);
+                        }
+                    }
+                    // pop sha
+                    uncommitedShas.shift();
+                }
+                return null;
             }
         });
     }

src/backport.ts

@@ -38,9 +38,11 @@ export type Config = {
 
 type Experimental = {
   detect_merge_method: boolean;
+  backport_on_conflicts: boolean;
 };
 const experimentalDefaults: Experimental = {
   detect_merge_method: false,
+  backport_on_conflicts: false,
 };
 export { experimentalDefaults };
 
@@ -265,8 +267,14 @@ export class Backport {
             continue;
           }
 
+          let uncommitedShas: string[] | null;
+
           try {
-            await this.git.cherryPick(commitShasToCherryPick, this.config.pwd);
+            uncommitedShas = await this.git.cherryPick(
+              commitShasToCherryPick,
+              this.config.experimental.backport_on_conflicts,
+              this.config.pwd,
+            );
           } catch (error) {
             const message = this.composeMessageForCherryPickFailure(
               target,
@@ -312,6 +320,7 @@ export class Backport {
             head: branchname,
             base: target,
             maintainer_can_modify: true,
+            draft: uncommitedShas !== null,
           });
 
           if (new_pr_response.status != 201) {
@@ -387,15 +396,43 @@ export class Backport {
             }
           }
 
-          const message = this.composeMessageForSuccess(new_pr.number, target);
-          successByTarget.set(target, true);
-          createdPullRequestNumbers.push(new_pr.number);
-          await this.github.createComment({
-            owner,
-            repo,
-            issue_number: pull_number,
-            body: message,
-          });
+          // post success message to original pr
+          {
+            const message =
+              uncommitedShas !== null
+                ? this.composeMessageForSuccessWithConflicts(
+                    new_pr.number,
+                    target,
+                    branchname,
+                    uncommitedShas,
+                  )
+                : this.composeMessageForSuccess(new_pr.number, target);
+
+            successByTarget.set(target, true);
+            createdPullRequestNumbers.push(new_pr.number);
+            await this.github.createComment({
+              owner,
+              repo,
+              issue_number: pull_number,
+              body: message,
+            });
+          }
+          // post message to new pr to resolve conflict
+          if (uncommitedShas !== null) {
+            const message: string = this.composeMessageToResolveConflicts(
+              target,
+              branchname,
+              uncommitedShas,
+              true,
+            );
+
+            await this.github.createComment({
+              owner,
+              repo,
+              issue_number: new_pr.number,
+              body: message,
+            });
+          }
         } catch (error) {
           if (error instanceof Error) {
             console.error(error.message);
@@ -460,6 +497,7 @@ export class Backport {
       target,
       branchname,
       commitShasToCherryPick,
+      false,
     );
     return dedent`Backport failed for \`${target}\`, ${reason}.
 
@@ -473,23 +511,49 @@ export class Backport {
     commitShasToCherryPick: string[],
   ): string {
     const reason = "because it was unable to cherry-pick the commit(s)";
-    const suggestion = this.composeSuggestion(
+    const suggestionToResolve = this.composeMessageToResolveConflicts(
       target,
       branchname,
       commitShasToCherryPick,
+      false,
     );
     return dedent`Backport failed for \`${target}\`, ${reason}.
 
-                  Please cherry-pick the changes locally and resolve any conflicts.
+                  ${suggestionToResolve}`;
+  }
+
+  private composeMessageToResolveConflicts(
+    target: string,
+    branchname: string,
+    commitShasToCherryPick: string[],
+    branchExist: boolean,
+  ): string {
+    const suggestion = this.composeSuggestion(
+      target,
+      branchname,
+      commitShasToCherryPick,
+      branchExist,
+    );
+
+    return dedent`Please cherry-pick the changes locally and resolve any conflicts.
                   ${suggestion}`;
   }
 
   private composeSuggestion(
     target: string,
     branchname: string,
     commitShasToCherryPick: string[],
+    branchExist: boolean,
   ) {
-    return dedent`\`\`\`bash
+    return branchExist
+      ? dedent`\`\`\`bash
+      git fetch origin ${target}
+      git worktree add -d .worktree/${branchname} origin/${target}
+      cd .worktree/${branchname}
+      git switch ${branchname}
+      git cherry-pick -x ${commitShasToCherryPick.join(" ")}
+      \`\`\``
+      : dedent`\`\`\`bash
       git fetch origin ${target}
       git worktree add -d .worktree/${branchname} origin/${target}
       cd .worktree/${branchname}
@@ -520,6 +584,24 @@ export class Backport {
                   - #${pr_number}`;
   }
 
+  private composeMessageForSuccessWithConflicts(
+    pr_number: number,
+    target: string,
+    branchname: string,
+    commitShasToCherryPick: string[],
+  ): string {
+    const suggestionToResolve = this.composeMessageToResolveConflicts(
+      target,
+      branchname,
+      commitShasToCherryPick,
+      true,
+    );
+    return dedent`Created backport PR for \`${target}\`:
+                  - #${pr_number} with remaining conflicts!
+
+                  ${suggestionToResolve}`;
+  }
+
   private createOutput(
     successByTarget: Map<string, boolean>,
     createdPullRequestNumbers: Array<number>,