It's time to start preparing for a version of redo that doesn't work
unless we build it first (because it will rely on C modules, and
eventually be rewritten in C altogether).
To get rolling, remove the old-style symlinks to the main programs, and
rename those programs from redo-*.py to redo/cmd_*.py. We'll also move
all library functions into the redo/ dir, which is a more python-style
naming convention.
Previously, install.do was generating wrappers for installing in
/usr/bin, which extend sys.path and then import+run the right file.
This made "installed" redo work quite differently from running redo
inside its source tree. Instead, let's always generate the wrappers in
bin/, and not make anything executable except those wrappers.
Since we're generating wrappers anyway, let's actually auto-detect the
right version of python for the running system; distros can't seem to
agree on what to call their python2 binaries (sigh). We'll fill in the
right #! shebang lines. Since we're doing that, we can stop using
/usr/bin/env, which will a) make things slightly faster, and b) let us
use "python -S", which tells python not to load a bunch of extra crap
we're not using, thus improving startup times.
Annoyingly, we now have to build redo using minimal/do, then run the
tests using bin/redo. To make this less annoying, we add a toplevel
./do script that knows the right steps, and a Makefile (whee!) for
people who are used to typing 'make' and 'make test' and 'make clean'.
In commit redo-0.11-4-g34669fb, we changed os.stat into os.lstat to
avoid false positives in the "manual override" detector: a .do file
that generates $3 as a symlink would trigger manual override if the
*target* of that symlink ever changed, which is incorrect.
Unfortunately using os.lstat() leads to a different problem: if X
depends on Y and Y is a symlink to Z, then X would not be rebuilt when
Z changes, which is clearly wrong.
The fix is twofold:
1. read_stamp() should change on changes to both the link itself,
*and* the target of the link.
2. We shouldn't mark a target as overridden under so many situations.
We'll use *only* the primary mtime of the os.lstat(), not all the
other bits in the stamp.
Step 2 fixes a few other false positives also. For example, if you
'cp -a' a whole tree to another location, the st_ino of all the targets
will change, which would trigger a mass of "manual override" warnings.
Although a change in inode is sufficient to count an input as having
changed (just to be extra safe), it should *not* be considered a manual
override. Now we can distinguish between the two.
Because the stamp format has changed, update the SCHEMA_VER field. I
should have done this every other time I changed the stamp format, but
I forgot. Sorry. That leads to spurious "manually modified" warnings
after upgrading redo.
On systems where 'python' refers to python3, redo
failed to launch. All invocations of python have been
made explicitly python2 invocations. All tests pass
on an Arch Linux system as of this commit.
