"Haritha  via GitGitGadget" [off-list ref] writes:

From: D Harithamma <redacted>

This fix avoids high memory footprint when adding files that require
conversion.  Git has a trace_encoding routine that prints trace output
when GIT_TRACE_WORKING_TREE_ENCODING=1 is set. This environment
variable is used to debug the encoding contents.  When a 40MB file is
added, it requests close to 1.8GB of storage from xrealloc which can
lead to out of memory errors.  However, the check for
GIT_TRACE_WORKING_TREE_ENCODING is done after the string is allocated.
This resolves high memory footprints even when
GIT_TRACE_WORKING_TREE_ENCODING is not active.  This fix adds an early
exit to avoid the unnecessary memory allocation.

The sentences jump around and the logic flow is hard to follow.  The
first sentence makes a claim of what it does (but the readers have
not bee told where that problem comes from).  The second sentence
makes a statement of a fact, but the readers do not yet know at that
point what relevance the fact has to the issue at hand, etc.

The usual way to compose a log message of this project is to

 - Give an observation on how the current system work in the present
   tense (so no need to say "Currently X is Y", just "X is Y"), and
   discuss what you perceive as a problem in it.

 - Propose a solution (optional---often, problem description
   trivially leads to an obvious solution in reader's minds).

 - Give commands to the codebase to "become like so".

in this order.


    When Git needs to add a file that require encoding conversion,
    but tracing of encoding conversion is *not* requested via
    setting GIT_TRACE_WORKING_TREE_ENCODING environment variable,
    the trace_encoding() function still allocated and prepared
    "human readable" copies of the file contents before and after
    conversion to show in the trace.  This wasted a lot of memory
    footprint and runtime cycles without giving any user-visible
    benefit.

    Exit early from the function when we we are not tracing before
    we spend all the effort, not after.

or something, perhaps?

I am wondering if we should be able to test this, but "git grep
GIT_TRACE_WORKING_TREE_ENCODING t/" is not finding any existing test
in the area.

Signed-off-by: Harithamma D <redacted>

This does not match the "From: " line above.  Please pick one way to
spell your name and identify yourself to this project, and use it
consistently.

Thanks.

The actual fix is so simple and nice ;-)