[PATCH v2 00/11] do not overuse strbuf_split*()

strbuf is a very good data structure to work with string data without having to worry about running past the end of the string.

But an array of strbuf is often a wrong data structure. You rarely have need to be able to edit multiple strings represented by such an array simultaneously. And strbuf_split*() that produces result in such a shape is a misdesigned API function.

The most common use case of strbuf_split*() family of functions seems to be to trim away the whitespaces around each piece of split string. With modern string_list_split*(), it is often no longer necessary.

This series builds on top of the other series that extends string list API to allow string_list_split() to take more than one delimiter bytes, and to optionally trim the resulting string pieces.

I do not plan to eradicate all the uses of strbuf_split*() myself, not because I found some valid use cases in the existing code (I haven't yet), but these patches would give interested others enough material to study and mimic to continue the effort and I can safely leave it as #leftoverbits to rewrite them.

Junio C Hamano (11):
  wt-status: avoid strbuf_split*()
  clean: do not pass strbuf by value
  clean: do not use strbuf_split*() [part 1]
  clean: do not use strbuf_split*() [part 2]
  merge-tree: do not use strbuf_split*()
  notes: do not use strbuf_split*()
  config: do not use strbuf_split()
  environment: do not use strbuf_split*()
  sub-process: do not use strbuf_split*()
  trace2: trim_trailing_newline followed by trim is a no-op
  trace2: do not use strbuf_split*()

 builtin/clean.c      | 74 ++++++++++++++++++++--------------------
 builtin/merge-tree.c | 30 +++++++++--------
 builtin/notes.c      | 23 +++++++------
 config.c             | 23 ++++++-------
 environment.c        | 19 +++++++----
 sub-process.c        | 15 ++++-----
 trace2/tr2_cfg.c     | 80 +++++++++++++++-----------------------------
 wt-status.c          | 31 ++++++-----------
 8 files changed, 129 insertions(+), 166 deletions(-)

 1:  79164fa6de =  1:  e254c0b462 wt-status: avoid strbuf_split*()
 2:  85006a11ff =  2:  07306ec99d clean: do not pass strbuf by value
 3:  633dd871f7 =  3:  1dc849eb0b clean: do not use strbuf_split*() [part 1]
 4:  60dd58af7e =  4:  69b885a579 clean: do not use strbuf_split*() [part 2]
 5:  49a6606d76 =  5:  ac90eb1b57 merge-tree: do not use strbuf_split*()
 6:  3813cc0e4d !  6:  68dd2be7ae notes: do not use strbuf_split*()
    @@ Metadata
      ## Commit message ##
         notes: do not use strbuf_split*()
     
    -    When reading the copy instruction from the standard input, the
    -    program reads a line, splits it into tokens at whitespace, and trims
    -    each of the tokens before using.  We no longer need to use strbuf
    -    just to be able to trimming, as string_list_split*() family now can
    -    trim while splitting a string.
    +    When reading copy instructions from the standard input, the program
    +    reads a line, splits it into tokens at whitespace, and trims each of
    +    the tokens before using.  We no longer need to use strbuf just to be
    +    able to trim, as string_list_split*() family now can trim while
    +    splitting a string.
     
    -    Retire the use of strbuf_split().
    +    Retire the use of strbuf_split() from this code path.
     
         Note that this loop is a bit sloppy in that it ensures at least
         there are two tokens on each line, but ignores if there are extra
 7:  2bd08bde36 !  7:  1f8c86ad0a config: do not use strbuf_split()
    @@ Commit message
         config: do not use strbuf_split()
     
         When parsing an old-style GIT_CONFIG_PARAMETERS environment
    -    variable, the code parses the key=value pair by spliting them at '='
    -    into an array of strbuf's.  As strbuf_split() leafes the delimiter
    +    variable, the code parses key=value pairs by splitting them at '='
    +    into an array of strbuf's.  As strbuf_split() leaves the delimiter
         at the end of the split piece, the code has to manually trim it.
     
         If we split with string_list_split(), that becomes unnecessary.
    -    Retire the use of strbuf_split().
    +    Retire the use of strbuf_split() from this code path.
     
         Note that the max parameter of string_list_split() is of
         an ergonomically iffy design---it specifies the maximum number of
 8:  ed35491fb1 =  8:  26c782fd7e environment: do not use strbuf_split*()
 9:  5b8fe54684 !  9:  95316b62fe sub-process: do not use strbuf_split*()
    @@ Commit message
         Signed-off-by: Junio C Hamano <gitster@pobox.com>
     
      ## sub-process.c ##
    -@@
    - #include "sub-process.h"
    - #include "sigchain.h"
    - #include "pkt-line.h"
    -+#include "string-list.h"
    - 
    - int cmd2process_cmp(const void *cmp_data UNUSED,
    - 		    const struct hashmap_entry *eptr,
     @@ sub-process.c: struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const ch
      
      int subprocess_read_status(int fd, struct strbuf *status)
 -:  ---------- > 10:  09e83741d2 trace2: trim_trailing_newline followed by trim is a no-op
 -:  ---------- > 11:  be9c9cb420 trace2: do not use strbuf_split*()