make test-mq-qdiff executable.

tests: new test for mq qdiff command `hg qdiff .' is supposed to work but it is currently broken. This test should help us verify when it gets fixed.

merge with other head by default, not tip. fixes issue 339.

merge with mpm.

Tune a bit the extdiff toplevel comments/samples. * Capitalize the first letter of all sentences * Add an example for GNU diff(1) 'context diff' mode. * Explain the requirement for separate cmd.xxx and opts.xxx options in .hgrc, which hopefully will guard against users trying to add: [extdiff] # Add a new Mercurial command called `cdiff', which calls # GNU diff(1) in 'context diff' mode. cmd.cdiff = diff -Nprc5 which fails for recent crew builds with: $ hg cdiff . making snapshot of 1 files from rev 07dc4a569f4e making snapshot of 1 files from working dir diff -Nprc5: not found The correct way to do this is by separating the cmd.cdiff and opts.cdiff parts like this: [extdiff] # Add a new Mercurial command called `cdiff', which calls # GNU diff(1) in 'context diff' mode. cmd.cdiff = diff opts.cdiff = -Nprc5 so add it as a new example and explicitly describe it in the extdiff comments.

filelog: add hash-based comparisons For status, rather than reconstruct full file versions from revlog for comparison, compare hashes.

Merge with crew

merge: minor simplification

Fixed test-extdiff. diff-like tools usually return 1 if differences are found. Currently the extdiff returns 256, but that's a different topic (consolidating return code handling in hg).

A fix for --prune.