[release-tools] Only read from the chromium checkout in v8rel.

Don't create local branches or otherwise manipulate the
checkout. This reads refs from remote branches and
reads file contents using show. It is faster and requires
less bootstrapping and cleanup.

TBR=tandrii@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1060013003

Cr-Commit-Position: refs/heads/master@{#27640}

tools/release/git_recipes.py

@@ -163,7 +163,7 @@ class GitRecipesMixin(object):
 
   @Strip
   def GitLog(self, n=0, format="", grep="", git_hash="", parent_hash="",
-             branch="", reverse=False, **kwargs):
+             branch="", path=None, reverse=False, **kwargs):
     assert not (git_hash and parent_hash)
     args = ["log"]
     if n > 0:
@@ -179,8 +179,15 @@ class GitRecipesMixin(object):
     if parent_hash:
       args.append("%s^" % parent_hash)
     args.append(branch)
+    if path:
+      args.extend(["--", path])
     return self.Git(MakeArgs(args), **kwargs)
 
+  def GitShowFile(self, refspec, path, **kwargs):
+    assert refspec
+    assert path
+    return self.Git(MakeArgs(["show", "%s:%s" % (refspec, path)]), **kwargs)
+
   def GitGetPatch(self, git_hash, **kwargs):
     assert git_hash
     return self.Git(MakeArgs(["log", "-1", "-p", git_hash]), **kwargs)
@@ -241,8 +248,8 @@ class GitRecipesMixin(object):
   def GitPull(self, **kwargs):
     self.Git("pull", **kwargs)
 
-  def GitFetchOrigin(self, **kwargs):
-    self.Git("fetch origin", **kwargs)
+  def GitFetchOrigin(self, *refspecs, **kwargs):
+    self.Git(MakeArgs(["fetch", "origin"] + list(refspecs)), **kwargs)
 
   @Strip
   # Copied from bot_update.py and modified for svn-like numbers only.

tools/release/releases.py

@@ -314,28 +314,16 @@ class RetrieveV8Releases(Step):
                               reverse=True)
 
 
-class SwitchChromium(Step):
-  MESSAGE = "Switch to Chromium checkout."
-
-  def RunStep(self):
-    cwd = self._options.chromium
-    # Check for a clean workdir.
-    if not self.GitIsWorkdirClean(cwd=cwd):  # pragma: no cover
-      self.Die("Workspace is not clean. Please commit or undo your changes.")
-    # Assert that the DEPS file is there.
-    if not os.path.exists(os.path.join(cwd, "DEPS")):  # pragma: no cover
-      self.Die("DEPS file not present.")
-
-
 class UpdateChromiumCheckout(Step):
-  MESSAGE = "Update the checkout and create a new branch."
+  MESSAGE = "Update the chromium checkout."
 
   def RunStep(self):
     cwd = self._options.chromium
-    self.GitCheckout("master", cwd=cwd)
-    self.GitPull(cwd=cwd)
-    self.DeleteBranch(self.Config("BRANCHNAME"), cwd=cwd)
-    self.GitCreateBranch(self.Config("BRANCHNAME"), cwd=cwd)
+    self.GitFetchOrigin("+refs/heads/*:refs/remotes/origin/*",
+                        "+refs/branch-heads/*:refs/remotes/branch-heads/*",
+                        cwd=cwd)
+    # Update v8 checkout in chromium.
+    self.GitFetchOrigin(cwd=os.path.join(cwd, "v8"))
 
 
 def ConvertToCommitNumber(step, revision):
@@ -352,9 +340,6 @@ class RetrieveChromiumV8Releases(Step):
   def RunStep(self):
     cwd = self._options.chromium
 
-    # Update v8 checkout in chromium.
-    self.GitFetchOrigin(cwd=os.path.join(cwd, "v8"))
-
     # All v8 revisions we are interested in.
     releases_dict = dict((r["revision_git"], r) for r in self["releases"])
 
@@ -362,12 +347,9 @@ class RetrieveChromiumV8Releases(Step):
     count_past_last_v8 = 0
     try:
       for git_hash in self.GitLog(
-          format="%H", grep="V8", cwd=cwd).splitlines():
-        if "DEPS" not in self.GitChangedFiles(git_hash, cwd=cwd):
-          continue
-        if not self.GitCheckoutFileSafe("DEPS", git_hash, cwd=cwd):
-          break  # pragma: no cover
-        deps = FileToText(os.path.join(cwd, "DEPS"))
+          format="%H", grep="V8", branch="origin/master",
+          path="DEPS", cwd=cwd).splitlines():
+        deps = self.GitShowFile(git_hash, "DEPS", cwd=cwd)
         match = DEPS_RE.search(deps)
         if match:
           cr_rev = self.GetCommitPositionNumber(git_hash, cwd=cwd)
@@ -378,7 +360,7 @@ class RetrieveChromiumV8Releases(Step):
           if count_past_last_v8:
             count_past_last_v8 += 1  # pragma: no cover
 
-          if count_past_last_v8 > 10:
+          if count_past_last_v8 > 20:
             break  # pragma: no cover
 
           # Stop as soon as we find a v8 revision that we didn't fetch in the
@@ -391,9 +373,6 @@ class RetrieveChromiumV8Releases(Step):
     except (KeyboardInterrupt, SystemExit):  # pragma: no cover
       pass
 
-    # Clean up.
-    self.GitCheckoutFileSafe("DEPS", "HEAD", cwd=cwd)
-
     # Add the chromium ranges to the v8 candidates and master releases.
     all_ranges = BuildRevisionRanges(cr_releases)
 
@@ -425,11 +404,8 @@ class RietrieveChromiumBranches(Step):
     count_past_last_v8 = 0
     try:
       for branch in branches:
-        if not self.GitCheckoutFileSafe("DEPS",
-                                        "branch-heads/%d" % branch,
-                                        cwd=cwd):
-          break  # pragma: no cover
-        deps = FileToText(os.path.join(cwd, "DEPS"))
+        deps = self.GitShowFile(
+            "refs/branch-heads/%d" % branch, "DEPS", cwd=cwd)
         match = DEPS_RE.search(deps)
         if match:
           v8_hsh = match.group(1)
@@ -438,7 +414,7 @@ class RietrieveChromiumBranches(Step):
           if count_past_last_v8:
             count_past_last_v8 += 1  # pragma: no cover
 
-          if count_past_last_v8 > 10:
+          if count_past_last_v8 > 20:
             break  # pragma: no cover
 
           # Stop as soon as we find a v8 revision that we didn't fetch in the
@@ -451,9 +427,6 @@ class RietrieveChromiumBranches(Step):
     except (KeyboardInterrupt, SystemExit):  # pragma: no cover
       pass
 
-    # Clean up.
-    self.GitCheckoutFileSafe("DEPS", "HEAD", cwd=cwd)
-
     # Add the chromium branches to the v8 candidate releases.
     all_ranges = BuildRevisionRanges(cr_branches)
     for revision, ranges in all_ranges.iteritems():
@@ -464,8 +437,6 @@ class CleanUp(Step):
   MESSAGE = "Clean up."
 
   def RunStep(self):
-    self.GitCheckout("master", cwd=self._options.chromium)
-    self.GitDeleteBranch(self.Config("BRANCHNAME"), cwd=self._options.chromium)
     self.CommonCleanup()
 
 
@@ -518,7 +489,6 @@ class Releases(ScriptsBase):
     return [
       Preparation,
       RetrieveV8Releases,
-      SwitchChromium,
       UpdateChromiumCheckout,
       RetrieveChromiumV8Releases,
       RietrieveChromiumBranches,

tools/release/test_scripts.py

@@ -1322,6 +1322,7 @@ Cr-Commit-Position: refs/heads/candidates@{#345}
 
 Cr-Commit-Position: refs/heads/4.2.71@{#1}
 """
+    c_deps = "Line\n   \"v8_revision\": \"%s\",\n  line\n"
 
     json_output = self.MakeEmptyTempFile()
     csv_output = self.MakeEmptyTempFile()
@@ -1331,10 +1332,6 @@ Cr-Commit-Position: refs/heads/4.2.71@{#1}
     chrome_dir = TEST_CONFIG["CHROMIUM"]
     chrome_v8_dir = os.path.join(chrome_dir, "v8")
     os.makedirs(chrome_v8_dir)
-    def WriteDEPS(revision):
-      TextToFile("Line\n   \"v8_revision\": \"%s\",\n  line\n" % revision,
-                 os.path.join(chrome_dir, "DEPS"))
-    WriteDEPS(567)
 
     def ResetVersion(major, minor, build, patch=0):
       return lambda: self.WriteFakeVersionFile(major=major,
@@ -1342,9 +1339,6 @@ Cr-Commit-Position: refs/heads/4.2.71@{#1}
                                                build=build,
                                                patch=patch)
 
-    def ResetDEPS(revision):
-      return lambda: WriteDEPS(revision)
-
     self.Expect([
       Cmd("git status -s -uno", ""),
       Cmd("git checkout -f origin/master", ""),
@@ -1403,47 +1397,25 @@ Cr-Commit-Position: refs/heads/4.2.71@{#1}
       Cmd("git log -1 --format=%ci hash_456", "02:15"),
       Cmd("git checkout -f HEAD -- %s" % VERSION_FILE, "",
           cb=ResetVersion(3, 22, 5)),
-      Cmd("git status -s -uno", "", cwd=chrome_dir),
-      Cmd("git checkout -f master", "", cwd=chrome_dir),
-      Cmd("git pull", "", cwd=chrome_dir),
-      Cmd("git branch", "  branch1\n* %s" % TEST_CONFIG["BRANCHNAME"],
-          cwd=chrome_dir),
-      Cmd("git branch -D %s" % TEST_CONFIG["BRANCHNAME"], "",
-          cwd=chrome_dir),
-      Cmd("git new-branch %s" % TEST_CONFIG["BRANCHNAME"], "",
+      Cmd("git fetch origin +refs/heads/*:refs/remotes/origin/* "
+          "+refs/branch-heads/*:refs/remotes/branch-heads/*", "",
           cwd=chrome_dir),
       Cmd("git fetch origin", "", cwd=chrome_v8_dir),
-      Cmd("git log --format=%H --grep=\"V8\"",
-          "c_hash0\nc_hash1\nc_hash2\nc_hash3\n",
-          cwd=chrome_dir),
-      Cmd("git diff --name-only c_hash0 c_hash0^", "", cwd=chrome_dir),
-      Cmd("git diff --name-only c_hash1 c_hash1^", "DEPS", cwd=chrome_dir),
-      Cmd("git checkout -f c_hash1 -- DEPS", "",
-          cb=ResetDEPS("hash_456"),
+      Cmd("git log --format=%H --grep=\"V8\" origin/master -- DEPS",
+          "c_hash1\nc_hash2\nc_hash3\n",
           cwd=chrome_dir),
+      Cmd("git show c_hash1:DEPS", c_deps % "hash_456", cwd=chrome_dir),
       Cmd("git log -1 --format=%B c_hash1", c_hash1_commit_log,
           cwd=chrome_dir),
-      Cmd("git diff --name-only c_hash2 c_hash2^", "DEPS", cwd=chrome_dir),
-      Cmd("git checkout -f c_hash2 -- DEPS", "",
-          cb=ResetDEPS("hash_345"),
-          cwd=chrome_dir),
+      Cmd("git show c_hash2:DEPS", c_deps % "hash_345", cwd=chrome_dir),
       Cmd("git log -1 --format=%B c_hash2", c_hash2_commit_log,
           cwd=chrome_dir),
-      Cmd("git diff --name-only c_hash3 c_hash3^", "DEPS", cwd=chrome_dir),
-      Cmd("git checkout -f c_hash3 -- DEPS", "", cb=ResetDEPS("deadbeef"),
-          cwd=chrome_dir),
+      Cmd("git show c_hash3:DEPS", c_deps % "deadbeef", cwd=chrome_dir),
       Cmd("git log -1 --format=%B c_hash3", c_hash3_commit_log,
           cwd=chrome_dir),
-      Cmd("git checkout -f HEAD -- DEPS", "", cb=ResetDEPS("hash_567"),
-          cwd=chrome_dir),
       Cmd("git branch -r", " weird/123\n  branch-heads/7\n", cwd=chrome_dir),
-      Cmd("git checkout -f branch-heads/7 -- DEPS", "",
-          cb=ResetDEPS("hash_345"),
-          cwd=chrome_dir),
-      Cmd("git checkout -f HEAD -- DEPS", "", cb=ResetDEPS("hash_567"),
+      Cmd("git show refs/branch-heads/7:DEPS", c_deps % "hash_345",
           cwd=chrome_dir),
-      Cmd("git checkout -f master", "", cwd=chrome_dir),
-      Cmd("git branch -D %s" % TEST_CONFIG["BRANCHNAME"], "", cwd=chrome_dir),
       Cmd("git checkout -f origin/master", ""),
       Cmd("git branch -D %s" % TEST_CONFIG["BRANCHNAME"], ""),
     ])