Download specific Patch Set for Review

Adds ability to request download and checkout
of specific review-patchset using syntax:
 git review -d <reviewId>,<patchsetNumber>

It will create and checkout the <author>/<topic>-patch<number> branch.

Change-Id: Idaf57acb1464e1e71a436d741ae889494a91d446

AUTHORS

@@ -5,3 +5,4 @@ Kiall Mac Innes <kiall@managedit.ie>
 Roan Kattouw <roan.kattouw@gmail.com>
 Antoine Musso <hashar@free.fr>
 Yuriy Taraday <yorik.sar@gmail.com>
+Pavel Sedlák <psedlak@redhat.com>

README.md

@@ -49,6 +49,10 @@ If you want to download change 781 from gerrit to review it::
 
     git review -d 781
 
+If you want to download patchset 4 for change 781 from gerrit to review it::
+
+    git review -d 781,4
+
 If you just want to do the commit message and remote setup steps::
 
     git review -s

git-review

@@ -639,12 +639,12 @@ class CannotQueryPatchSet(CommandFailed):
     EXIT_CODE = 34
 
 
-class PatchSetInformationNotFound(ChangeSetException):
+class ReviewInformationNotFound(ChangeSetException):
     "Could not fetch review information for change %s"
     EXIT_CODE = 35
 
 
-class PatchSetNotFound(ChangeSetException):
+class ReviewNotFound(ChangeSetException):
     "Gerrit review %s not found"
     EXIT_CODE = 36
 
@@ -656,6 +656,11 @@ Does specified change number belong to this project?"""
     EXIT_CODE = 37
 
 
+class PatchSetNotFound(ChangeSetException):
+    "Review patchset %s not found"
+    EXIT_CODE = 38
+
+
 class CheckoutNewBranchFailed(CommandFailed):
     "Cannot checkout to new branch"
     EXIT_CODE = 64
@@ -685,12 +690,19 @@ def fetch_review(review, masterbranch, remote):
     else:
         userhost = "%s@%s" % (username, hostname)
 
+    review_arg = review
+    patchset_number = None
+    patchset_opt = '--current-patch-set'
+    if ',' in review:
+        review, patchset_number = review.split(',')
+        patchset_opt = '--patch-sets'
+
     review_info = None
     output = run_command_exc(
         CannotQueryPatchSet,
         "ssh", "-x", port, userhost,
         "gerrit", "query",
-        "--format=JSON --current-patch-set change:%s" % review)
+        "--format=JSON %s change:%s" % (patchset_opt, review))
 
     review_jsons = output.split("\n")
     found_review = False
@@ -705,12 +717,19 @@ def fetch_review(review, masterbranch, remote):
     if not found_review:
         if VERBOSE:
             print(output)
-        raise PatchSetInformationNotFound(review)
+        raise ReviewInformationNotFound(review)
 
     try:
-        refspec = review_info['currentPatchSet']['ref']
+        if patchset_number is None:
+            refspec = review_info['currentPatchSet']['ref']
+        else:
+            refspec = [ps for ps
+                       in review_info['patchSets']
+                       if ps['number'] == patchset_number][0]['ref']
+    except IndexError:
+        raise PatchSetNotFound(review_arg)
     except KeyError:
-        raise PatchSetNotFound(review)
+        raise ReviewNotFound(review)
 
     try:
         topic = review_info['topic']
@@ -722,7 +741,11 @@ def fetch_review(review, masterbranch, remote):
         author = re.sub('\W+', '_', review_info['owner']['name']).lower()
     except KeyError:
         author = 'unknown'
-    branch_name = "review/%s/%s" % (author, topic)
+
+    if patchset_number is None:
+        branch_name = "review/%s/%s" % (author, topic)
+    else:
+        branch_name = "review/%s/%s-patch%s" % (author, topic, patchset_number)
 
     print("Downloading %s from gerrit" % refspec)
     run_command_exc(PatchSetGitFetchFailed,

git-review.1

@@ -46,6 +46,12 @@ designed to make it easier to apprehend Gerrit, especially for
 users that have recently switched to Git from another version
 control system.
 .Pp
+.Ar change
+can be changeNumber as obtained using
+.Fl --list
+option, or it can be changeNumber,patchsetNumber for fetching exact patchset from the change.
+In that case local branch will get -patch[patchsetNumber] suffix.
+.Pp
 The following options are available:
 .Bl -tag -width indent
 .It Fl d Ar change , Fl -download= Ns Ar change
@@ -197,6 +203,8 @@ Cannot fetch information about the changeset to be downloaded.
 Changeset not found.
 .It 37
 Particular patchset cannot be fetched from the remote git repository.
+.It 38
+Specified patchset number not found in the changeset.
 .It 64
 Cannot checkout downloaded patchset into the new branch.
 .It 65
@@ -239,6 +247,18 @@ $ git branch
 Gerrit looks up both name of the author and the topic name from Gerrit
 to name a local branch. This facilitates easier identification of changes.
 .Pp
+To fetch a remote patchset number 5 from change number 3004:
+.Pp
+.Bd -literal -offset indent
+$ git-review -d 3004,5
+Downloading refs/changes/04/3004/5 from gerrit into
+review/someone/topic_name-patch5
+Switched to branch 'review/someone/topic_name-patch5
+$ git branch
+  master
+* review/author/topic_name-patch5
+.Ed
+.Pp
 To send a change for review and delete local branch afterwards:
 .Bd -literal -offset indent
 $ git-review -f