users can provide commitish when creating a release

[finishes #99189274]

Signed-off-by: Chris Walter <cwalter@pivotal.io>

README.md

@@ -51,6 +51,9 @@ matching the patterns in `globs` to the release.
 * `tag`: *Required.* A path to a file containing the name of the Git tag to use
   for the release.
 
+* `commitish`: *Optional.* A path to a file containing the commitish (SHA, tag,
+  branch name) that the release should be associated with.
+
 * `body`: *Optional.* A path to a file containing the body text of the release.
 
 * `globs`: *Optional.* A list of globs for files that will be uploaded alongside

out_command.go

@@ -44,10 +44,19 @@ func (c *OutCommand) Run(sourceDir string, request OutRequest) (OutResponse, err
 		}
 	}
 
+	targetCommitish := ""
+	if request.Params.CommitishPath != "" {
+		targetCommitish, err = c.fileContents(filepath.Join(sourceDir, request.Params.CommitishPath))
+		if err != nil {
+			return OutResponse{}, err
+		}
+	}
+
 	release := &github.RepositoryRelease{
 		Name:            github.String(name),
 		TagName:         github.String(tag),
 		Body:            github.String(body),
+		TargetCommitish: github.String(targetCommitish),
 	}
 
 	existingReleases, err := c.github.ListReleases()
@@ -66,6 +75,7 @@ func (c *OutCommand) Run(sourceDir string, request OutRequest) (OutResponse, err
 	if existingRelease != nil {
 		existingRelease.Name = github.String(name)
 		existingRelease.Body = github.String(body)
+		existingRelease.TargetCommitish = github.String(targetCommitish)
 
 		for _, asset := range existingRelease.Assets {
 			fmt.Fprintf(c.writer, "clearing existing asset: %s\n", *asset.Name)

out_command_test.go

@@ -100,19 +100,39 @@ var _ = Describe("Out Command", func() {
 			}
 		})
 
+		It("deletes the existing assets", func() {
+			Ω(githubClient.DeleteReleaseAssetCallCount()).Should(Equal(2))
+
+			Ω(githubClient.DeleteReleaseAssetArgsForCall(0)).Should(Equal(existingAssets[0]))
+			Ω(githubClient.DeleteReleaseAssetArgsForCall(1)).Should(Equal(existingAssets[1]))
+		})
+
+		Context("when a commitish is not supplied", func() {
 			It("updates the existing release", func() {
 				Ω(githubClient.UpdateReleaseCallCount()).Should(Equal(1))
 
 				updatedRelease := githubClient.UpdateReleaseArgsForCall(0)
 				Ω(*updatedRelease.Name).Should(Equal("v0.3.12"))
 				Ω(*updatedRelease.Body).Should(Equal("this is a great release"))
+				Ω(updatedRelease.TargetCommitish).Should(Equal(github.String("")))
+			})
 		})
 
-		It("deletes the existing assets", func() {
-			Ω(githubClient.DeleteReleaseAssetCallCount()).Should(Equal(2))
+		Context("when a commitish is supplied", func() {
+			BeforeEach(func() {
+				commitishPath := filepath.Join(sourcesDir, "commitish")
+				file(commitishPath, "1z22f1")
+				request.Params.CommitishPath = "commitish"
+			})
 
-			Ω(githubClient.DeleteReleaseAssetArgsForCall(0)).Should(Equal(existingAssets[0]))
-			Ω(githubClient.DeleteReleaseAssetArgsForCall(1)).Should(Equal(existingAssets[1]))
+			It("updates the existing release", func() {
+				Ω(githubClient.UpdateReleaseCallCount()).Should(Equal(1))
+
+				updatedRelease := githubClient.UpdateReleaseArgsForCall(0)
+				Ω(*updatedRelease.Name).Should(Equal("v0.3.12"))
+				Ω(*updatedRelease.Body).Should(Equal("this is a great release"))
+				Ω(updatedRelease.TargetCommitish).Should(Equal(github.String("1z22f1")))
+			})
 		})
 	})
 
@@ -132,6 +152,31 @@ var _ = Describe("Out Command", func() {
 			}
 		})
 
+		Context("with a commitish", func() {
+			BeforeEach(func() {
+				commitishPath := filepath.Join(sourcesDir, "commitish")
+				file(commitishPath, "a2f4a3")
+				request.Params.CommitishPath = "commitish"
+			})
+
+			It("creates a release on GitHub with the commitish", func() {
+				Ω(githubClient.CreateReleaseCallCount()).Should(Equal(1))
+				release := githubClient.CreateReleaseArgsForCall(0)
+
+				Ω(release.TargetCommitish).Should(Equal(github.String("a2f4a3")))
+			})
+		})
+
+		Context("without a commitish", func() {
+			It("creates a release on GitHub without the commitish", func() {
+				Ω(githubClient.CreateReleaseCallCount()).Should(Equal(1))
+				release := githubClient.CreateReleaseArgsForCall(0)
+
+				// GitHub treats empty string the same as not suppying the field.
+				Ω(release.TargetCommitish).Should(Equal(github.String("")))
+			})
+		})
+
 		Context("with a body", func() {
 			BeforeEach(func() {
 				bodyPath := filepath.Join(sourcesDir, "body")

resources.go

@@ -37,6 +37,7 @@ type OutParams struct {
 	NamePath      string `json:"name"`
 	BodyPath      string `json:"body"`
 	TagPath       string `json:"tag"`
+	CommitishPath string `json:"commitsh"`
 
 	Globs []string `json:"globs"`
 }