trydiff: join filename with prefix only once

trydiff: collect header-writing in one place This is the first step towards simplifying the big loop in trydiff(). This will make both the header code and the non-header code clearer, and it prepares for further simplification of the many nested if-statements in the body of the loop.

trydiff: make variable names more consistent Use '1' and '2' as suffix for names just like in the parameters 'ctx[12]': to,tn -> content1,content2 a,b -> f1, f2 omode,mode -> mode1,mode2 omode,nmode -> mode1,mode2 onode,nnode -> node1,node2 oflag,nflag -> flag1,flag2 oindex,nindex -> index1,index2

trydiff: check only if added file is a copy target, not source When creating a diff with copy/rename enabled, we consider added files and check if they are either copy sources or targets. However, an added file should never be a copy source. The test suite seems to agree with this: all tests pass if we raise an exception when an added file is a copy source. So, let's simplify the code by dropping the conditions that are never true. For those interested in the historical reasons: Before commit d1f209bb9564 (patch: separate reverse copy data (issue1959), 2010-02-11), 'copy' seems to have been a bidirectional map. Then that commit split it up into two unidirectional maps and duplicated the logic to look in both maps. It was still needed at that point to look in both maps, as the copy detection was poor and could sometimes be reported in reverse. A little later came 91eb4512edd0 (copies: rewrite copy detection for non-merge users, 2012-01-04). That commit fixed the copy detection to be backwards when it should, and made the hacks in trydiff unnecessary.

trydiff: remove unused variable 'modifiedset' We started updating 'modifiedset' in a9853fc172d2 (trydiff: simplify checking for additions, 2014-12-23) but in the same commit, we removed the last use of the variable. Clean it up.

revset: replace parsing alias definition by _parsealiasdefn to parse strictly Before this patch, referring alias arguments is parsed by string base operation "str.replace". This causes problems below (see the previous patch introducing "_parsealiasdefn" for detail) - the shorter name argument breaks referring the longer name - argument names in the quoted string are broken This patch replaces parsing alias definition by "_parsealiasdefn" to parse strictly.

revset: introduce _parsealiasdefn to parse alias definitions strictly This patch introduces "_parsealiasdefn" to parse alias definitions strictly. For example, it can avoid problems below, which current implementation can't. - the shorter name argument breaks referring the longer name one in the definition, if the former is completely prefix of the latter for example, the alias definition "foo($1, $10) = $1 or $10" is parsed as "_aliasarg('$1') or _aliasarg('$1')0" and causes parse error, because tail "0" of "_aliasarg('$1')0" is invalid. - argument names in the quoted string are broken for example, the definition "foo($1) = $1 or desc('$1')" is parsed as "_aliasarg('$1') or desc('_aliasarg(\'$1\')')" and causes unexpected description matching against not '$1' but '_aliasarg(\'$1\')'. To decrease complication of patch, current implementation for alias definitions is replaced by "_parsealiasdefn" in the subsequent patch. This patch just introduces it. This patch defines "_parsealiasdefn" not as a method of "revsetalias" class but as a one of "revset" module, because of ease of testing by doctest.

hgweb: use revset.spanset where appropriate It is remainder of 9ad6dae67845 where spanset was introduced.