debugcommands: introduce actions to perform deterministic reads
"readavailable" is useful as a debugging device to see what data is
available on a pipe. But the mechanism isn't deterministic because
what's available on a pipe is highly conditional on timing, system
load, OS behavior, etc. This makes it not suitable for tests.
We introduce "ereadline," "read," and "eread" for performing
deterministic I/O operations (at least on blocking file descriptors).
We stop short of converting existing consumers of "readavailable"
in tests because we're working out race conditions and deadlocks
on Windows. But the goal is to eventually move tests away from
"readavailable" to these new APIs.
Differential Revision: https://phab.mercurial-scm.org/D2720
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)