Subject: [PATCH v5 0/6] Xdiff cleanup part 3

From: "Ezekiel Newren via GitGitGadget" <[email-masked]>
Date: Wed, 08 Apr 2026 20:26:22 +0000

Changes in v5:

 * drop commit "xdiff/xdl_cleanup_records: simplify INVESTIGATE handling for
   clarity".
 * add braces around the else clause

I didn't see a better way to rewrite how action is used so I reverted to
what it used to be.

Changes in v4:

 * Change SIZE_MAX to PTRDIFF_MAX.

Changes in v3:

 * run make DEVELOPER=1 on each commit and fix all compiler issues

v2 is a radical departure from v1 Changes in v2:

 * make the flow of xdl_cleanup_records() easier to follow

There is no performance or behavioral change introduced in this patch
series.

=== original cover letter bellow ===

Patch series summary:

 * patch 1: Introduce the ivec type
 * patch 2: Create the function xdl_do_classic_diff()
 * patches 3-4: generic cleanup
 * patches 5-8: convert from dstart/dend (in xdfile_t) to
   delta_start/delta_end (in xdfenv_t)
 * patches 9-10: move xdl_cleanup_records(), and related, from xprepare.c to
   xdiffi.c

Things that will be addressed in future patch series:

 * Make xdl_cleanup_records() easier to read
 * convert recs/nrec into an ivec
 * convert changed to an ivec
 * remove reference_index/nreff from xdfile_t and turn it into an ivec
 * splitting minimal_perfect_hash out as its own ivec
 * improve the performance of the classifier and parsing/hashing lines

=== before this patch series typedef struct s_xdfile { xrecord_t *recs;
size_t nrec; ptrdiff_t dstart, dend; bool *changed; size_t *reference_index;
size_t nreff; } xdfile_t;

typedef struct s_xdfenv { xdfile_t xdf1, xdf2; } xdfenv_t;

=== after this patch series typedef struct s_xdfile { xrecord_t *recs;
size_t nrec; bool *changed; size_t *reference_index; size_t nreff; }
xdfile_t;

typedef struct s_xdfenv { xdfile_t xdf1, xdf2; size_t delta_start,
delta_end; size_t mph_size; } xdfenv_t;

Ezekiel Newren (6):
  xdiff/xdl_cleanup_records: delete local recs pointer
  xdiff: use unambiguous types in xdl_bogo_sqrt()
  xdiff/xdl_cleanup_records: use unambiguous types
  xdiff/xdl_cleanup_records: make limits more clear
  xdiff/xdl_cleanup_records: make setting action easier to follow
  xdiff/xdl_cleanup_records: put braces around the else clause

 xdiff/xdiffi.c   |  2 +-
 xdiff/xprepare.c | 56 +++++++++++++++++++++++++++++++-----------------
 xdiff/xutils.c   |  4 ++--
 xdiff/xutils.h   |  2 +-
 4 files changed, 40 insertions(+), 24 deletions(-)

base-commit: ca1db8a0f7dc0dbea892e99f5b37c5fe5861be71
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2156%2Fezekielnewren%2Fxdiff-cleanup-3-v5
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2156/ezekielnewren/xdiff-cleanup-3-v5
Pull-Request: https://github.com/git/git/pull/2156

Range-diff vs v4:

 1:  da32a9747c = 1:  b31924a949 xdiff/xdl_cleanup_records: delete local recs pointer
 2:  86b0ad100c = 2:  1822166fef xdiff: use unambiguous types in xdl_bogo_sqrt()
 3:  39a35365ae = 3:  85aa0da90c xdiff/xdl_cleanup_records: use unambiguous types
 4:  75fe3ea125 = 4:  fec2b0f38a xdiff/xdl_cleanup_records: make limits more clear
 5:  0cf1412d01 = 5:  88c68fa89a xdiff/xdl_cleanup_records: make setting action easier to follow
 6:  fd14ccafc4 ! 6:  699e198fa9 xdiff/xdl_cleanup_records: simplify INVESTIGATE handling for clarity
     @@ Metadata
      Author: Ezekiel Newren <[email-masked]>
      
       ## Commit message ##
     -    xdiff/xdl_cleanup_records: simplify INVESTIGATE handling for clarity
     -
     -    Make it clear that INVESTIGATE is turned into KEEP or DISCARD based on
     -    the result of xdl_clean_mmatch() which reduces actionX[i] into a
     -    boolean value.
     +    xdiff/xdl_cleanup_records: put braces around the else clause
      
          Signed-off-by: Ezekiel Newren <[email-masked]>
      
       ## xdiff/xprepare.c ##
      @@ xdiff/xprepare.c: static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
     - 	 */
     - 	xdf1->nreff = 0;
     - 	for (i = xdf1->dstart; i <= xdf1->dend; i++) {
     --		if (action1[i] == KEEP ||
     --		    (action1[i] == INVESTIGATE && !xdl_clean_mmatch(action1, i, xdf1->dstart, xdf1->dend))) {
     -+		if (action1[i] == INVESTIGATE) {
     -+			if (!xdl_clean_mmatch(action1, i, xdf1->dstart, xdf1->dend))
     -+				action1[i] = KEEP;
     -+			else
     -+				action1[i] = DISCARD;
     -+		}
     -+
     -+		if (action1[i] == KEEP) {
     + 		    (action1[i] == INVESTIGATE && !xdl_clean_mmatch(action1, i, xdf1->dstart, xdf1->dend))) {
       			xdf1->reference_index[xdf1->nreff++] = i;
     --			/* changed[i] remains false, i.e. keep */
     + 			/* changed[i] remains false, i.e. keep */
      -		} else
     -+			/* changed[i] remains false */
     -+		} else if (action1[i] == DISCARD)
     ++		} else {
       			xdf1->changed[i] = true;
     --			/* i.e. discard */
     -+		else
     -+			BUG("Illegal state for action1[i]");
     + 			/* i.e. discard */
     ++		}
       	}
       
       	xdf2->nreff = 0;
     - 	for (i = xdf2->dstart; i <= xdf2->dend; i++) {
     --		if (action2[i] == KEEP ||
     --		    (action2[i] == INVESTIGATE && !xdl_clean_mmatch(action2, i, xdf2->dstart, xdf2->dend))) {
     -+		if (action2[i] == INVESTIGATE) {
     -+			if (!xdl_clean_mmatch(action2, i, xdf2->dstart, xdf2->dend))
     -+				action2[i] = KEEP;
     -+			else
     -+				action2[i] = DISCARD;
     -+		}
     -+
     -+		if (action2[i] == KEEP) {
     +@@ xdiff/xprepare.c: static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
     + 		    (action2[i] == INVESTIGATE && !xdl_clean_mmatch(action2, i, xdf2->dstart, xdf2->dend))) {
       			xdf2->reference_index[xdf2->nreff++] = i;
     --			/* changed[i] remains false, i.e. keep */
     + 			/* changed[i] remains false, i.e. keep */
      -		} else
     -+			/* changed[i] remains false */
     -+		} else if (action2[i] == DISCARD)
     ++		} else {
       			xdf2->changed[i] = true;
     --			/* i.e. discard */
     -+		else
     -+			BUG("Illegal state for action2[i]");
     + 			/* i.e. discard */
     ++		}
       	}
       
       cleanup:

-- 
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