extdiff: do single file diffs from the wc with no copy
Extdiff was always making a temporary directory and copying files even when not required. This change makes extdiff avoid the copy when diffing a single file that lives in the wc. This lets external diff tools edit the working copy file directly. It also lets other extensions resuse the functions in extdiff and get in-place diffs.
adding a
adding b
Only in a: a
Only in a: b
diffing a.000000000000 a
hg falabala [OPTION]... [FILE]...
use 'echo' to diff repository (or selected files)
Show differences between revisions for the specified
files, using the 'echo' program.
When two revision arguments are given, then changes are
shown between those revisions. If only one revision is
specified then that revision is compared to the working
directory, and, when no revisions are specified, the
working directory files are compared to its parent.
options:
-o --option pass option to comparison program
-r --rev revision
-I --include include names matching the given patterns
-X --exclude exclude names matching the given patterns
use "hg -v help falabala" to show global options
diffing a.8a5febb7f867/a a.34eed99112ab/a
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
diff-like tools yield a non-zero exit code
diffing a.34eed99112ab/c [tmp]/test-extdiff/a/c