prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Checking out Bazaar branch makes full clone
  When checking out a Bazaar branch, pip currently makes a full clone of the branch history. This is unnecessary and much slower than just fetching the latest revision:
  
  For example, performance on my system for 'bzr co --lightweight lp:bzr':
  
  0.60s user 0.11s system 5% cpu 12.234 total
  
  Performance on my system for 'bzr branch lp:bzr':
  
  65.41s user 1.48s system 39% cpu 2:47.91 total
  
  
  </issue>
  <code>
  [start of src/pip/_internal/vcs/bazaar.py]
  1 import logging
  2 from typing import List, Optional, Tuple
  3 
  4 from pip._internal.utils.misc import HiddenText, display_path
  5 from pip._internal.utils.subprocess import make_command
  6 from pip._internal.utils.urls import path_to_url
  7 from pip._internal.vcs.versioncontrol import (
  8     AuthInfo,
  9     RemoteNotFoundError,
  10     RevOptions,
  11     VersionControl,
  12     vcs,
  13 )
  14 
  15 logger = logging.getLogger(__name__)
  16 
  17 
  18 class Bazaar(VersionControl):
  19     name = "bzr"
  20     dirname = ".bzr"
  21     repo_name = "branch"
  22     schemes = (
  23         "bzr+http",
  24         "bzr+https",
  25         "bzr+ssh",
  26         "bzr+sftp",
  27         "bzr+ftp",
  28         "bzr+lp",
  29         "bzr+file",
  30     )
  31 
  32     @staticmethod
  33     def get_base_rev_args(rev: str) -> List[str]:
  34         return ["-r", rev]
  35 
  36     def fetch_new(
  37         self, dest: str, url: HiddenText, rev_options: RevOptions, verbosity: int
  38     ) -> None:
  39         rev_display = rev_options.to_display()
  40         logger.info(
  41             "Checking out %s%s to %s",
  42             url,
  43             rev_display,
  44             display_path(dest),
  45         )
  46         if verbosity <= 0:
  47             flag = "--quiet"
  48         elif verbosity == 1:
  49             flag = ""
  50         else:
  51             flag = f"-{'v'*verbosity}"
  52         cmd_args = make_command("branch", flag, rev_options.to_args(), url, dest)
  53         self.run_command(cmd_args)
  54 
  55     def switch(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:
  56         self.run_command(make_command("switch", url), cwd=dest)
  57 
  58     def update(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:
  59         cmd_args = make_command("pull", "-q", rev_options.to_args())
  60         self.run_command(cmd_args, cwd=dest)
  61 
  62     @classmethod
  63     def get_url_rev_and_auth(cls, url: str) -> Tuple[str, Optional[str], AuthInfo]:
  64         # hotfix the URL scheme after removing bzr+ from bzr+ssh:// readd it
  65         url, rev, user_pass = super().get_url_rev_and_auth(url)
  66         if url.startswith("ssh://"):
  67             url = "bzr+" + url
  68         return url, rev, user_pass
  69 
  70     @classmethod
  71     def get_remote_url(cls, location: str) -> str:
  72         urls = cls.run_command(
  73             ["info"], show_stdout=False, stdout_only=True, cwd=location
  74         )
  75         for line in urls.splitlines():
  76             line = line.strip()
  77             for x in ("checkout of branch: ", "parent branch: "):
  78                 if line.startswith(x):
  79                     repo = line.split(x)[1]
  80                     if cls._is_local_repository(repo):
  81                         return path_to_url(repo)
  82                     return repo
  83         raise RemoteNotFoundError
  84 
  85     @classmethod
  86     def get_revision(cls, location: str) -> str:
  87         revision = cls.run_command(
  88             ["revno"],
  89             show_stdout=False,
  90             stdout_only=True,
  91             cwd=location,
  92         )
  93         return revision.splitlines()[-1]
  94 
  95     @classmethod
  96     def is_commit_id_equal(cls, dest: str, name: Optional[str]) -> bool:
  97         """Always assume the versions don't match"""
  98         return False
  99 
  100 
  101 vcs.register(Bazaar)
  102
  [end of src/pip/_internal/vcs/bazaar.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/src/pip/_internal/vcs/bazaar.py b/src/pip/_internal/vcs/bazaar.py
  --- a/src/pip/_internal/vcs/bazaar.py
  +++ b/src/pip/_internal/vcs/bazaar.py
  @@ -49,14 +49,25 @@
               flag = ""
           else:
               flag = f"-{'v'*verbosity}"
  -        cmd_args = make_command("branch", flag, rev_options.to_args(), url, dest)
  +        cmd_args = make_command(
  +            "checkout", "--lightweight", flag, rev_options.to_args(), url, dest
  +        )
           self.run_command(cmd_args)
   
       def switch(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:
           self.run_command(make_command("switch", url), cwd=dest)
   
       def update(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:
  -        cmd_args = make_command("pull", "-q", rev_options.to_args())
  +        output = self.run_command(
  +            make_command("info"), show_stdout=False, stdout_only=True, cwd=dest
  +        )
  +        if output.startswith("Standalone "):
  +            # Older versions of pip used to create standalone branches.
  +            # Convert the standalone branch to a checkout by calling "bzr bind".
  +            cmd_args = make_command("bind", "-q", url)
  +            self.run_command(cmd_args, cwd=dest)
  +
  +        cmd_args = make_command("update", "-q", rev_options.to_args())
           self.run_command(cmd_args, cwd=dest)
   
       @classmethod
  
verification_info: {"golden_diff": "diff --git a/src/pip/_internal/vcs/bazaar.py b/src/pip/_internal/vcs/bazaar.py\n--- a/src/pip/_internal/vcs/bazaar.py\n+++ b/src/pip/_internal/vcs/bazaar.py\n@@ -49,14 +49,25 @@\n             flag = \"\"\n         else:\n             flag = f\"-{'v'*verbosity}\"\n-        cmd_args = make_command(\"branch\", flag, rev_options.to_args(), url, dest)\n+        cmd_args = make_command(\n+            \"checkout\", \"--lightweight\", flag, rev_options.to_args(), url, dest\n+        )\n         self.run_command(cmd_args)\n \n     def switch(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:\n         self.run_command(make_command(\"switch\", url), cwd=dest)\n \n     def update(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:\n-        cmd_args = make_command(\"pull\", \"-q\", rev_options.to_args())\n+        output = self.run_command(\n+            make_command(\"info\"), show_stdout=False, stdout_only=True, cwd=dest\n+        )\n+        if output.startswith(\"Standalone \"):\n+            # Older versions of pip used to create standalone branches.\n+            # Convert the standalone branch to a checkout by calling \"bzr bind\".\n+            cmd_args = make_command(\"bind\", \"-q\", url)\n+            self.run_command(cmd_args, cwd=dest)\n+\n+        cmd_args = make_command(\"update\", \"-q\", rev_options.to_args())\n         self.run_command(cmd_args, cwd=dest)\n \n     @classmethod\n", "issue": "Checking out Bazaar branch makes full clone\nWhen checking out a Bazaar branch, pip currently makes a full clone of the branch history. This is unnecessary and much slower than just fetching the latest revision:\r\n\r\nFor example, performance on my system for 'bzr co --lightweight lp:bzr':\r\n\r\n0.60s user 0.11s system 5% cpu 12.234 total\r\n\r\nPerformance on my system for 'bzr branch lp:bzr':\r\n\r\n65.41s user 1.48s system 39% cpu 2:47.91 total\r\n\n", "before_files": [{"content": "import logging\nfrom typing import List, Optional, Tuple\n\nfrom pip._internal.utils.misc import HiddenText, display_path\nfrom pip._internal.utils.subprocess import make_command\nfrom pip._internal.utils.urls import path_to_url\nfrom pip._internal.vcs.versioncontrol import (\n    AuthInfo,\n    RemoteNotFoundError,\n    RevOptions,\n    VersionControl,\n    vcs,\n)\n\nlogger = logging.getLogger(__name__)\n\n\nclass Bazaar(VersionControl):\n    name = \"bzr\"\n    dirname = \".bzr\"\n    repo_name = \"branch\"\n    schemes = (\n        \"bzr+http\",\n        \"bzr+https\",\n        \"bzr+ssh\",\n        \"bzr+sftp\",\n        \"bzr+ftp\",\n        \"bzr+lp\",\n        \"bzr+file\",\n    )\n\n    @staticmethod\n    def get_base_rev_args(rev: str) -> List[str]:\n        return [\"-r\", rev]\n\n    def fetch_new(\n        self, dest: str, url: HiddenText, rev_options: RevOptions, verbosity: int\n    ) -> None:\n        rev_display = rev_options.to_display()\n        logger.info(\n            \"Checking out %s%s to %s\",\n            url,\n            rev_display,\n            display_path(dest),\n        )\n        if verbosity <= 0:\n            flag = \"--quiet\"\n        elif verbosity == 1:\n            flag = \"\"\n        else:\n            flag = f\"-{'v'*verbosity}\"\n        cmd_args = make_command(\"branch\", flag, rev_options.to_args(), url, dest)\n        self.run_command(cmd_args)\n\n    def switch(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:\n        self.run_command(make_command(\"switch\", url), cwd=dest)\n\n    def update(self, dest: str, url: HiddenText, rev_options: RevOptions) -> None:\n        cmd_args = make_command(\"pull\", \"-q\", rev_options.to_args())\n        self.run_command(cmd_args, cwd=dest)\n\n    @classmethod\n    def get_url_rev_and_auth(cls, url: str) -> Tuple[str, Optional[str], AuthInfo]:\n        # hotfix the URL scheme after removing bzr+ from bzr+ssh:// readd it\n        url, rev, user_pass = super().get_url_rev_and_auth(url)\n        if url.startswith(\"ssh://\"):\n            url = \"bzr+\" + url\n        return url, rev, user_pass\n\n    @classmethod\n    def get_remote_url(cls, location: str) -> str:\n        urls = cls.run_command(\n            [\"info\"], show_stdout=False, stdout_only=True, cwd=location\n        )\n        for line in urls.splitlines():\n            line = line.strip()\n            for x in (\"checkout of branch: \", \"parent branch: \"):\n                if line.startswith(x):\n                    repo = line.split(x)[1]\n                    if cls._is_local_repository(repo):\n                        return path_to_url(repo)\n                    return repo\n        raise RemoteNotFoundError\n\n    @classmethod\n    def get_revision(cls, location: str) -> str:\n        revision = cls.run_command(\n            [\"revno\"],\n            show_stdout=False,\n            stdout_only=True,\n            cwd=location,\n        )\n        return revision.splitlines()[-1]\n\n    @classmethod\n    def is_commit_id_equal(cls, dest: str, name: Optional[str]) -> bool:\n        \"\"\"Always assume the versions don't match\"\"\"\n        return False\n\n\nvcs.register(Bazaar)\n", "path": "src/pip/_internal/vcs/bazaar.py"}]}