tests/test-histedit-templates.t

worker: avoid potential partial write of pickled data

Previously, the code wrote the pickled data using os.write(). However,
os.write() can write less bytes than passed to it. To trigger the problem, the
pickled data had to be larger than 2147479552 bytes on my system.

Instead, open a file object and pass it to pickle.dump(). This also has the
advantage that it doesn’t buffer the whole pickled data in memory.

Note that the opened file must be buffered because pickle doesn’t support
unbuffered streams because unbuffered streams’ write() method might write less
bytes than passed to it (like os.write()) but pickle.dump() relies on that all
bytes are written (see https://github.com/python/cpython/issues/93050).

The side effect of using a file object and a with statement is that wfd is
explicitly closed now while it seems like before it was implicitly closed by
process exit.

Testing templating for histedit command

Setup

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > [experimental]
  > evolution=createmarkers
  > EOF

  $ hg init repo
  $ cd repo
  $ for ch in a b c d; do echo foo > $ch; hg commit -Aqm "Added "$ch; done

  $ hg log -G -T "{rev}:{node|short} {desc}"
  @  3:62615734edd5 Added d
  |
  o  2:28ad74487de9 Added c
  |
  o  1:29becc82797a Added b
  |
  o  0:18d04c59bb5d Added a
  
Getting the JSON output for nodechanges

  $ hg histedit -Tjson --commands - 2>&1 <<EOF
  > pick 28ad74487de9 Added c
  > pick 62615734edd5 Added d
  > pick 18d04c59bb5d Added a
  > pick 29becc82797a Added b
  > EOF
  [
   {
    "nodechanges": {"18d04c59bb5d2d4090ad9a5b59bd6274adb63add": ["109f8ec895447f81b380ba8d4d8b66539ccdcb94"], "28ad74487de9599d00d81085be739c61fc340652": ["bff9e07c1807942b161dab768aa793b48e9a7f9d"], "29becc82797a4bc11ec8880b58eaecd2ab3e7760": ["f5dcf3b4db23f31f1aacf46c33d1393de303d26f"], "62615734edd52f06b6fb9c2beb429e4fe30d57b8": ["201423b441c84d9e6858daed653e0d22485c1cfa"]}
   }
  ]

  $ hg log -G -T "{rev}:{node|short} {desc}"
  @  7:f5dcf3b4db23 Added b
  |
  o  6:109f8ec89544 Added a
  |
  o  5:201423b441c8 Added d
  |
  o  4:bff9e07c1807 Added c
  
  $ hg histedit -T "{nodechanges|json}" --commands - 2>&1 <<EOF
  > pick bff9e07c1807 Added c
  > pick 201423b441c8 Added d
  > pick 109f8ec89544 Added a
  > roll f5dcf3b4db23 Added b
  > EOF
  {"109f8ec895447f81b380ba8d4d8b66539ccdcb94": ["8d01470bfeab64d3de13c49adb79d88790d38396"], "f3ec56a374bdbdf1953cacca505161442c6f3a3e": [], "f5dcf3b4db23f31f1aacf46c33d1393de303d26f": ["8d01470bfeab64d3de13c49adb79d88790d38396"]} (no-eol)