* [RFC PATCH 0/3] diff: pair edited lines inside moved blocks
@ 2026-05-27 4:23 Keita Oda
2026-05-27 4:24 ` [RFC PATCH 1/3] diff: add word-diff-align line pairing Keita Oda
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Keita Oda @ 2026-05-27 4:23 UTC (permalink / raw)
To: git; +Cc: Keita ODA
From: Keita ODA <ainsophyao@gmail•com>
This is an RFC for a review aid, not a proposed final UI or option name.
The motivation is the gap between --word-diff and --color-moved.
--word-diff is very useful when the line-level diff already found useful
old/new line pairs. --color-moved is useful when moved lines are exact
matches. But when a block is moved and one line inside the block is edited,
the small edit can be buried in a large delete/add region.
That case matters for review. A one-line move is usually easy to inspect by
eye. A ten-line moved block with a one-character change inside it is harder
to audit. A small synthetic permission-table example in patch 3 uses this
shape:
-#define PERM_RESOURCE_EXPORT 0x0008
+#define PERM_RESOURCE_EXPORT 0x0001
That particular toy example is not meant to show something that
--color-moved cannot see. It is meant to make the review question small:
can Git expose "this moved line was also edited" in a lightweight way?
The real-world cases below are less about proving that existing modes are
blind, and more about making the row-to-row correspondence explicit enough
that the small edits are easy to check.
This series adds an opt-in prototype, --word-diff-align, that post-processes
the emitted diff symbols and tries to pair similar deleted and inserted lines.
It does not change the underlying diff algorithm, patch semantics, apply, or
merge behavior.
The prototype is deliberately language-agnostic. It does not parse source
code or build an AST; it only tokenizes diff lines into small text tokens and
scores local token overlap. This keeps the experiment applicable to code,
tests, generated tables, documentation, and other text files.
The prototype is intentionally split into three pieces:
* patch 1 adds the candidate retrieval and line-pair scoring, and exposes
selected pairs with an RFC/debug comment;
* patch 2 adds a small RFC-only renderer that inserts word-diff-like
markers on the selected pairs, so that the recovered pairs are easier to
inspect;
* patch 3 adds a focused test case.
The current prototype is still larger than I would like, but the split keeps
the experimental pieces visible. The full series is about 1000 inserted
lines; roughly 800 lines are option plumbing, tokenization, candidate
retrieval, scoring, pair selection, and debug comments, while about 200 lines
are temporary rendering code for review.
The scoring model is:
S = W + aL
where W is a 5-line-window token overlap score and L is a center-line token
LCS score. A small 64-bit window fingerprint is used only as a candidate
retrieval index; candidate pairs are scored again before they are selected.
Tokens repeated in the surrounding small window carry less weight for the
center-line score, which is a local-IDF-like approximation. This keeps tokens
such as "import" or "#define" from overwhelming the line-specific identifier.
Some real-world examples that motivated the prototype:
* CPython opcode/metadata renumbering, where many table rows stay logically
paired but their numeric values shift;
* CPython test parameterization rewrites such as tuple rows becoming
dict(input=..., expected=...) rows;
* Git's own expected-output tables, where a column width change adds spaces
across many rows and a row insertion shifts the surrounding context;
* Git's own remote.c refactoring, where extracted helper code has small
identifier changes.
As a rough trigger-rate sanity check, I ran the prototype over 5734 changed
file pairs sampled from recent Git, CPython, and Rust history. The stricter
"crossing and edited" signal, which ignores the many adjacent row pairs and
looks for pairs that cross another recovered pair, appeared in 739 file pairs
(about 13%). This is not a gold-label quality number, but it suggests that
the mode is not only triggering on the synthetic test.
A small manual review found both clear wins and loose matches.
I found the problem easiest to inspect with four-way comparisons:
* git diff --histogram
* git diff --histogram --word-diff=plain
* git diff --histogram --color-moved=blocks
* git diff --histogram --word-diff-align
I put a small set of rendered four-way examples here:
https://oda.github.io/git-diff-rfc-examples/rfc-word-diff-align/
These links are supplemental; the patch series is intended to be readable
without them.
Known limitations:
* the UI/debug output is not final;
* generated or boilerplate-heavy hunks, especially Rust generated test
updates, can still produce loose matches;
* one-line long-distance pairs are often less useful than block-level pairs;
* the prototype intentionally gives local and remote pairs similar treatment
for now, to make the recovered pairings visible for discussion;
* thresholds and tie-breaking are still experimental.
The question for this RFC is whether this kind of language-agnostic line-pair
annotation is worth pursuing in core, and if so whether it should be shaped as
word-diff plumbing, a color-moved extension, or a separate opt-in mode.
Keita ODA (3):
diff: add word-diff-align line pairing
diff: render word-diff-align pairs for RFC review
t4034: cover moved-and-edited word diff alignment
diff.c | 996 +++++++++++++++++++++++++++++++++++++++++-
diff.h | 1 +
t/t4034-diff-words.sh | 46 ++
3 files changed, 1035 insertions(+), 8 deletions(-)
--
2.39.3 (Apple Git-146)
^ permalink raw reply [flat|nested] 4+ messages in thread
* [RFC PATCH 1/3] diff: add word-diff-align line pairing
2026-05-27 4:23 [RFC PATCH 0/3] diff: pair edited lines inside moved blocks Keita Oda
@ 2026-05-27 4:24 ` Keita Oda
2026-05-27 4:24 ` [RFC PATCH 2/3] diff: render word-diff-align pairs for RFC review Keita Oda
2026-05-27 4:24 ` [RFC PATCH 3/3] t4034: cover moved-and-edited word diff alignment Keita Oda
2 siblings, 0 replies; 4+ messages in thread
From: Keita Oda @ 2026-05-27 4:24 UTC (permalink / raw)
To: git; +Cc: Keita ODA
From: Keita ODA <ainsophyao@gmail•com>
Add an opt-in --word-diff-align mode that post-processes emitted diff
symbols and tries to pair similar deleted and inserted lines inside each hunk.
This is not a replacement for the diff algorithm. The normal diff is produced
first; the new code only annotates the already-emitted symbols for review.
The candidate search is intentionally approximate. Each line is tokenized into
word-ish runs and single non-space symbols. Each token gets a hash, each line
gets a compact 64-bit fingerprint, and each changed line also gets a small
surrounding window fingerprint. Inserted-side windows are placed into bit
buckets, and deleted-side windows query those buckets to avoid a full all-pairs
scan in typical cases.
The fingerprint is only a retrieval index. Candidate pairs are scored again
using token hashes:
W = unique token overlap in the small surrounding windows
L = center-line token LCS score
S = W + 4L
For the center-line score, tokens repeated in the surrounding window carry less
weight. This is a local-IDF-like approximation: in a run of "import" or
"#define" lines, the repeated keyword is weak evidence, while the identifier
specific to the center line remains strong evidence.
For this RFC, selected pairs are exposed with a debug-style "# aligned ..."
comment. The next patch adds a small renderer to make the selected pairs more
readable.
---
diff.c | 809 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
diff.h | 1 +
2 files changed, 802 insertions(+), 8 deletions(-)
diff --git a/diff.c b/diff.c
index 397e38b41..6b8744920 100644
--- a/diff.c
+++ b/diff.c
@@ -46,6 +46,7 @@
#include "setup.h"
#include "strmap.h"
#include "ws.h"
+#include "ewah/ewok.h"
#ifdef NO_FAST_WORKING_DIRECTORY
#define FAST_WORKING_DIRECTORY 0
@@ -1358,6 +1359,774 @@ static void dim_moved_lines(struct diff_options *o)
}
}
+struct word_diff_align_line_info {
+ uint64_t bits;
+ int token_start;
+ int token_nr;
+};
+
+struct word_diff_align_item {
+ int symbol;
+ int change_pos;
+ int line_no;
+};
+
+struct word_diff_align_candidate {
+ int old_pos;
+ int new_pos;
+ int score;
+ int window_score;
+ int window_shared;
+ int line_score;
+ int line_shared;
+};
+
+#define WORD_DIFF_ALIGN_NUMBER_HASH 0x9e3779b9U
+
+#define WORD_DIFF_ALIGN_WINDOW_SIZE 2
+#define WORD_DIFF_ALIGN_FINGERPRINT_BITS 64
+#define WORD_DIFF_ALIGN_BIT_BUCKET_MAX 256
+#define WORD_DIFF_ALIGN_WINDOW_MIN_SCORE 35
+#define WORD_DIFF_ALIGN_WINDOW_MIN_SHARED 4
+#define WORD_DIFF_ALIGN_LINE_WEIGHT 4
+#define WORD_DIFF_ALIGN_SCORE_MIN 175
+
+static void word_diff_align_window_bounds(int nr, int pos,
+ int *start_p, int *end_p)
+{
+ int radius = WORD_DIFF_ALIGN_WINDOW_SIZE;
+
+ *start_p = pos > radius ? pos - radius : 0;
+ *end_p = pos + radius + 1 < nr ? pos + radius + 1 : nr;
+}
+
+static int word_diff_align_payload_len(const struct emitted_diff_symbol *e)
+{
+ int len = e->len;
+
+ if (len && e->line[len - 1] == '\n')
+ len--;
+ if (len && e->line[len - 1] == '\r')
+ len--;
+ return len;
+}
+
+static int word_diff_align_word_byte(char ch)
+{
+ return isalnum((unsigned char)ch) || ch == '_';
+}
+
+static int word_diff_align_numeric_token(const char *line, int start, int end)
+{
+ int i;
+
+ for (i = start; i < end; i++)
+ if (!isdigit((unsigned char)line[i]))
+ return 0;
+ return start < end;
+}
+
+static uint64_t word_diff_align_token_bits(unsigned int hash)
+{
+ return (1ULL << (hash & 63)) | (1ULL << ((hash >> 6) & 63));
+}
+
+static int word_diff_align_next_token(const char *line, int len, int *pos,
+ int *start_p, int *end_p)
+{
+ while (*pos < len && isspace((unsigned char)line[*pos]))
+ (*pos)++;
+ if (*pos == len)
+ return 0;
+
+ *start_p = *pos;
+ if (word_diff_align_word_byte(line[*pos]))
+ while (*pos < len && word_diff_align_word_byte(line[*pos]))
+ (*pos)++;
+ else
+ (*pos)++;
+ *end_p = *pos;
+ return 1;
+}
+
+static void word_diff_align_prepare_line(const struct emitted_diff_symbol *e,
+ struct word_diff_align_line_info *line,
+ unsigned int **tokens,
+ int *tokens_nr,
+ int *tokens_alloc)
+{
+ int len = word_diff_align_payload_len(e);
+ int pos = 0;
+ int start, end;
+
+ line->bits = 0;
+ line->token_start = *tokens_nr;
+ while (word_diff_align_next_token(e->line, len, &pos, &start, &end)) {
+ int numeric = word_diff_align_numeric_token(e->line, start, end);
+ unsigned int hash = numeric ? WORD_DIFF_ALIGN_NUMBER_HASH :
+ memhash(e->line + start, end - start);
+
+ ALLOC_GROW(*tokens, *tokens_nr + 1, *tokens_alloc);
+ (*tokens)[*tokens_nr] = hash;
+ line->bits |= word_diff_align_token_bits(hash);
+ (*tokens_nr)++;
+ }
+ line->token_nr = *tokens_nr - line->token_start;
+}
+
+static uint64_t word_diff_align_window_bits(struct word_diff_align_line_info *lines,
+ int nr, int pos)
+{
+ uint64_t bits = 0;
+ int start, end;
+ int i;
+
+ word_diff_align_window_bounds(nr, pos, &start, &end);
+ for (i = start; i < end; i++)
+ bits |= lines[i].bits;
+ return bits;
+}
+
+static int word_diff_align_filter_score(uint64_t a, uint64_t b, int *shared_p)
+{
+ int shared = ewah_bit_popcount64(a & b);
+ int total = ewah_bit_popcount64(a | b);
+
+ *shared_p = shared;
+ return total ? shared * 100 / total : 0;
+}
+
+static int word_diff_align_line_has_token(const struct word_diff_align_line_info *line,
+ const unsigned int *tokens,
+ unsigned int hash);
+
+static int word_diff_align_window_has_token(const struct word_diff_align_line_info *lines,
+ int start, int end,
+ const unsigned int *tokens,
+ unsigned int hash)
+{
+ int i;
+
+ for (i = start; i < end; i++)
+ if (word_diff_align_line_has_token(&lines[i], tokens, hash))
+ return 1;
+ return 0;
+}
+
+static int word_diff_align_window_seen_token(const struct word_diff_align_line_info *lines,
+ int start, int line_pos,
+ int token_pos,
+ const unsigned int *tokens,
+ unsigned int hash)
+{
+ int i;
+
+ for (i = start; i <= line_pos; i++) {
+ const struct word_diff_align_line_info *line = &lines[i];
+ int end = i == line_pos ? token_pos : line->token_nr;
+ int j;
+
+ for (j = 0; j < end; j++)
+ if (tokens[line->token_start + j] == hash)
+ return 1;
+ }
+ return 0;
+}
+
+static int word_diff_align_window_token_score(const struct word_diff_align_line_info *minus_lines,
+ int minus_nr, int minus_pos,
+ const unsigned int *minus_tokens,
+ const struct word_diff_align_line_info *plus_lines,
+ int plus_nr, int plus_pos,
+ const unsigned int *plus_tokens,
+ int *shared_p)
+{
+ int minus_start, minus_end, plus_start, plus_end;
+ int minus_unique = 0, plus_unique = 0, shared = 0;
+ int i;
+
+ word_diff_align_window_bounds(minus_nr, minus_pos, &minus_start,
+ &minus_end);
+ word_diff_align_window_bounds(plus_nr, plus_pos, &plus_start,
+ &plus_end);
+
+ for (i = minus_start; i < minus_end; i++) {
+ const struct word_diff_align_line_info *line = &minus_lines[i];
+ int j;
+
+ for (j = 0; j < line->token_nr; j++) {
+ unsigned int hash = minus_tokens[line->token_start + j];
+
+ if (word_diff_align_window_seen_token(minus_lines,
+ minus_start, i, j,
+ minus_tokens,
+ hash))
+ continue;
+ minus_unique++;
+ if (word_diff_align_window_has_token(plus_lines,
+ plus_start, plus_end,
+ plus_tokens, hash))
+ shared++;
+ }
+ }
+
+ for (i = plus_start; i < plus_end; i++) {
+ const struct word_diff_align_line_info *line = &plus_lines[i];
+ int j;
+
+ for (j = 0; j < line->token_nr; j++) {
+ unsigned int hash = plus_tokens[line->token_start + j];
+
+ if (word_diff_align_window_seen_token(plus_lines,
+ plus_start, i, j,
+ plus_tokens,
+ hash))
+ continue;
+ plus_unique++;
+ }
+ }
+
+ *shared_p = shared;
+ return minus_unique + plus_unique - shared ?
+ shared * 100 / (minus_unique + plus_unique - shared) : 0;
+}
+
+static int word_diff_align_line_has_token(const struct word_diff_align_line_info *line,
+ const unsigned int *tokens,
+ unsigned int hash)
+{
+ int i;
+
+ for (i = 0; i < line->token_nr; i++)
+ if (tokens[line->token_start + i] == hash)
+ return 1;
+ return 0;
+}
+
+static int word_diff_align_surrounding_line_freq(const struct word_diff_align_line_info *lines,
+ int nr, int pos,
+ const unsigned int *tokens,
+ unsigned int hash)
+{
+ int radius = WORD_DIFF_ALIGN_WINDOW_SIZE;
+ int start = pos > radius ? pos - radius : 0;
+ int end = pos + radius + 1 < nr ? pos + radius + 1 : nr;
+ int i, freq = 0;
+
+ for (i = start; i < end; i++) {
+ if (i == pos)
+ continue;
+ if (word_diff_align_line_has_token(&lines[i], tokens, hash))
+ freq++;
+ }
+ return freq;
+}
+
+static int word_diff_align_shared_token_value(const struct word_diff_align_line_info *minus_lines,
+ int minus_nr, int minus_pos,
+ const unsigned int *minus_tokens,
+ const struct word_diff_align_line_info *plus_lines,
+ int plus_nr, int plus_pos,
+ const unsigned int *plus_tokens,
+ unsigned int hash)
+{
+ int minus_freq = word_diff_align_surrounding_line_freq(minus_lines,
+ minus_nr,
+ minus_pos,
+ minus_tokens,
+ hash);
+ int plus_freq = word_diff_align_surrounding_line_freq(plus_lines,
+ plus_nr,
+ plus_pos,
+ plus_tokens,
+ hash);
+ int freq = minus_freq > plus_freq ? minus_freq : plus_freq;
+ int value = 2 * WORD_DIFF_ALIGN_WINDOW_SIZE - freq;
+
+ return value > 0 ? value : 0;
+}
+
+static int word_diff_align_unmatched_weight(const struct word_diff_align_line_info *line,
+ const unsigned int *tokens,
+ const unsigned int *other_tokens,
+ int other_start, int other_nr)
+{
+ int i, weight = 0;
+
+ for (i = 0; i < line->token_nr; i++) {
+ unsigned int hash = tokens[line->token_start + i];
+ int j, matched = 0;
+
+ for (j = 0; j < other_nr; j++) {
+ if (hash == other_tokens[other_start + j]) {
+ matched = 1;
+ break;
+ }
+ }
+ if (!matched)
+ weight++;
+ }
+ return weight;
+}
+
+static int word_diff_align_line_token_score(const struct word_diff_align_line_info *minus,
+ const struct word_diff_align_line_info *minus_lines,
+ int minus_nr, int minus_pos,
+ const unsigned int *minus_tokens,
+ const struct word_diff_align_line_info *plus,
+ const struct word_diff_align_line_info *plus_lines,
+ int plus_nr, int plus_pos,
+ const unsigned int *plus_tokens,
+ int *shared_p)
+{
+ int i, j, shared;
+ int *lcs;
+ int unmatched, total;
+
+ if (!minus->token_nr || !plus->token_nr) {
+ *shared_p = 0;
+ return 0;
+ }
+
+ CALLOC_ARRAY(lcs, plus->token_nr + 1);
+ for (i = 0; i < minus->token_nr; i++) {
+ unsigned int minus_hash = minus_tokens[minus->token_start + i];
+ int prev = 0;
+
+ for (j = 0; j < plus->token_nr; j++) {
+ unsigned int plus_hash = plus_tokens[plus->token_start + j];
+ int column = j + 1;
+ int saved;
+
+ saved = lcs[column];
+ if (minus_hash == plus_hash) {
+ int value = word_diff_align_shared_token_value(minus_lines,
+ minus_nr,
+ minus_pos,
+ minus_tokens,
+ plus_lines,
+ plus_nr,
+ plus_pos,
+ plus_tokens,
+ minus_hash);
+ int best = prev + value;
+
+ if (lcs[column] > best)
+ best = lcs[column];
+ if (lcs[column - 1] > best)
+ best = lcs[column - 1];
+ lcs[column] = best;
+ }
+ else if (lcs[column - 1] > lcs[column])
+ lcs[column] = lcs[column - 1];
+ prev = saved;
+ }
+ }
+
+ shared = lcs[plus->token_nr];
+ free(lcs);
+ unmatched = word_diff_align_unmatched_weight(minus, minus_tokens,
+ plus_tokens,
+ plus->token_start,
+ plus->token_nr) +
+ word_diff_align_unmatched_weight(plus, plus_tokens,
+ minus_tokens,
+ minus->token_start,
+ minus->token_nr);
+ total = 2 * shared + unmatched;
+ *shared_p = shared;
+ return total ? shared * 200 / total : 0;
+}
+
+static int word_diff_align_pair_score(int window_score,
+ const struct word_diff_align_line_info *minus,
+ const struct word_diff_align_line_info *minus_lines,
+ int minus_nr, int minus_pos,
+ const unsigned int *minus_tokens,
+ const struct word_diff_align_line_info *plus,
+ const struct word_diff_align_line_info *plus_lines,
+ int plus_nr, int plus_pos,
+ const unsigned int *plus_tokens,
+ int *line_score_p,
+ int *line_shared_p)
+{
+ int line_score, line_shared;
+
+ line_score = word_diff_align_line_token_score(minus, minus_lines,
+ minus_nr, minus_pos,
+ minus_tokens,
+ plus, plus_lines,
+ plus_nr, plus_pos,
+ plus_tokens, &line_shared);
+ *line_score_p = line_score;
+ *line_shared_p = line_shared;
+
+ /*
+ * The bit fingerprint is only a retrieval approximation. The window
+ * score passed here is computed from exact token hashes in the 5-line
+ * windows, while the line score gives the center line an additional
+ * identity bonus.
+ */
+ return window_score + WORD_DIFF_ALIGN_LINE_WEIGHT * line_score;
+}
+
+static int word_diff_align_candidate_cmp(const void *va, const void *vb)
+{
+ const struct word_diff_align_candidate *a = va;
+ const struct word_diff_align_candidate *b = vb;
+
+ if (a->score != b->score)
+ return b->score - a->score;
+ if (a->line_score != b->line_score)
+ return b->line_score - a->line_score;
+ if (a->window_score != b->window_score)
+ return b->window_score - a->window_score;
+ if (a->line_shared != b->line_shared)
+ return b->line_shared - a->line_shared;
+ if (a->window_shared != b->window_shared)
+ return b->window_shared - a->window_shared;
+ if (a->old_pos != b->old_pos)
+ return a->old_pos - b->old_pos;
+ return a->new_pos - b->new_pos;
+}
+
+static void word_diff_align_add_candidate(struct word_diff_align_candidate **candidates,
+ int *candidates_nr,
+ int *candidates_alloc,
+ int old_pos, int new_pos,
+ int score, int window_score,
+ int window_shared, int line_score,
+ int line_shared)
+{
+ struct word_diff_align_candidate *candidate;
+
+ ALLOC_GROW(*candidates, *candidates_nr + 1, *candidates_alloc);
+ candidate = &(*candidates)[(*candidates_nr)++];
+ candidate->old_pos = old_pos;
+ candidate->new_pos = new_pos;
+ candidate->score = score;
+ candidate->window_score = window_score;
+ candidate->window_shared = window_shared;
+ candidate->line_score = line_score;
+ candidate->line_shared = line_shared;
+}
+
+static void word_diff_align_debug_append_comment(struct emitted_diff_symbol *line,
+ const struct strbuf *suffix)
+{
+ struct strbuf out = STRBUF_INIT;
+ char *old_line = (char *)line->line;
+ size_t new_len;
+
+ if (line->len && line->line[line->len - 1] == '\n') {
+ strbuf_add(&out, line->line, line->len - 1);
+ strbuf_addbuf(&out, suffix);
+ strbuf_addch(&out, '\n');
+ } else {
+ strbuf_add(&out, line->line, line->len);
+ strbuf_addbuf(&out, suffix);
+ }
+ line->line = strbuf_detach(&out, &new_len);
+ line->len = (int)new_len;
+ free(old_line);
+}
+
+static void word_diff_align_debug_mark_pair(struct emitted_diff_symbol *minus_line,
+ struct emitted_diff_symbol *plus_line,
+ int minus_lineno, int plus_lineno,
+ int changed, int moved,
+ int window_score,
+ int line_score,
+ int pair_score)
+{
+ struct strbuf suffix = STRBUF_INIT;
+
+ if (moved) {
+ minus_line->flags |= DIFF_SYMBOL_MOVED_LINE;
+ plus_line->flags |= DIFF_SYMBOL_MOVED_LINE;
+ }
+
+ strbuf_addf(&suffix,
+ " # aligned from %d to %d, %s, W=%d L=%d S=%d",
+ minus_lineno, plus_lineno,
+ changed ? "edited" : "unchanged",
+ window_score, line_score, pair_score);
+ word_diff_align_debug_append_comment(minus_line, &suffix);
+ word_diff_align_debug_append_comment(plus_line, &suffix);
+ strbuf_release(&suffix);
+}
+
+static void word_diff_align_add_item(struct word_diff_align_item **items,
+ int *items_nr, int *items_alloc,
+ int symbol, int change_pos, int line_no)
+{
+ ALLOC_GROW(*items, *items_nr + 1, *items_alloc);
+ (*items)[*items_nr].symbol = symbol;
+ (*items)[*items_nr].change_pos = change_pos;
+ (*items)[*items_nr].line_no = line_no;
+ (*items_nr)++;
+}
+
+static void word_diff_align_hunk_start(const struct emitted_diff_symbols *e,
+ int start, int *old_lineno,
+ int *new_lineno)
+{
+ const char *line;
+ char *endp;
+
+ *old_lineno = 0;
+ *new_lineno = 0;
+ if (start <= 0 || e->buf[start - 1].s != DIFF_SYMBOL_CONTEXT_FRAGINFO)
+ return;
+ line = e->buf[start - 1].line;
+ if (!starts_with(line, "@@ -"))
+ return;
+ line += 4;
+ if (!isdigit((unsigned char)*line))
+ return;
+ *old_lineno = strtol(line, &endp, 10);
+ line = endp;
+ if (*line == ',') {
+ line++;
+ strtol(line, &endp, 10);
+ line = endp;
+ }
+ if (!starts_with(line, " +"))
+ return;
+ line += 2;
+ if (!isdigit((unsigned char)*line))
+ return;
+ *new_lineno = strtol(line, &endp, 10);
+}
+
+static int word_diff_align_local_pair(int old_pos, int new_pos)
+{
+ return old_pos == new_pos;
+}
+
+static void word_diff_align_hunk(struct emitted_diff_symbols *e, int start, int end)
+{
+ struct word_diff_align_item *old_items = NULL, *new_items = NULL;
+ int old_items_nr = 0, old_items_alloc = 0;
+ int new_items_nr = 0, new_items_alloc = 0;
+ int minus_nr = 0, plus_nr = 0;
+ struct word_diff_align_line_info *old_lines = NULL, *new_lines = NULL;
+ unsigned int *old_tokens = NULL, *new_tokens = NULL;
+ int old_tokens_nr = 0, old_tokens_alloc = 0;
+ int new_tokens_nr = 0, new_tokens_alloc = 0;
+ uint64_t *new_contexts = NULL;
+ int *bucket_heads = NULL, *bucket_next = NULL, *bucket_counts = NULL;
+ int *candidate_counts = NULL, *candidate_touched = NULL;
+ char *used_old = NULL, *used_plus = NULL;
+ struct word_diff_align_candidate *candidates = NULL;
+ int candidates_nr = 0, candidates_alloc = 0;
+ int old_lineno, new_lineno;
+ int i, j;
+
+ word_diff_align_hunk_start(e, start, &old_lineno, &new_lineno);
+ for (i = start; i < end; i++) {
+ if (e->buf[i].s == DIFF_SYMBOL_MINUS) {
+ word_diff_align_add_item(&old_items, &old_items_nr,
+ &old_items_alloc, i, minus_nr++,
+ old_lineno++);
+ } else if (e->buf[i].s == DIFF_SYMBOL_PLUS) {
+ word_diff_align_add_item(&new_items, &new_items_nr,
+ &new_items_alloc, i, plus_nr++,
+ new_lineno++);
+ } else if (e->buf[i].s == DIFF_SYMBOL_CONTEXT) {
+ word_diff_align_add_item(&old_items, &old_items_nr,
+ &old_items_alloc, i, -1,
+ old_lineno++);
+ word_diff_align_add_item(&new_items, &new_items_nr,
+ &new_items_alloc, i, -1,
+ new_lineno++);
+ }
+ }
+
+ if (!minus_nr || !plus_nr)
+ goto cleanup;
+
+ CALLOC_ARRAY(old_lines, old_items_nr);
+ CALLOC_ARRAY(new_lines, new_items_nr);
+ CALLOC_ARRAY(new_contexts, new_items_nr);
+ CALLOC_ARRAY(bucket_heads, WORD_DIFF_ALIGN_FINGERPRINT_BITS);
+ CALLOC_ARRAY(bucket_counts, WORD_DIFF_ALIGN_FINGERPRINT_BITS);
+ CALLOC_ARRAY(bucket_next, new_items_nr * WORD_DIFF_ALIGN_FINGERPRINT_BITS);
+ CALLOC_ARRAY(candidate_counts, new_items_nr);
+ CALLOC_ARRAY(candidate_touched, new_items_nr);
+ CALLOC_ARRAY(used_old, minus_nr);
+ CALLOC_ARRAY(used_plus, plus_nr);
+
+ for (i = 0; i < old_items_nr; i++)
+ word_diff_align_prepare_line(&e->buf[old_items[i].symbol], &old_lines[i],
+ &old_tokens, &old_tokens_nr,
+ &old_tokens_alloc);
+ for (i = 0; i < new_items_nr; i++)
+ word_diff_align_prepare_line(&e->buf[new_items[i].symbol], &new_lines[i],
+ &new_tokens, &new_tokens_nr,
+ &new_tokens_alloc);
+ for (i = 0; i < new_items_nr; i++)
+ new_contexts[i] = word_diff_align_window_bits(new_lines, new_items_nr, i);
+
+ for (i = 0; i < new_items_nr; i++) {
+ if (new_items[i].change_pos < 0)
+ continue;
+ for (j = 0; j < WORD_DIFF_ALIGN_FINGERPRINT_BITS; j++) {
+ uint64_t bit = 1ULL << j;
+
+ if (!(new_contexts[i] & bit))
+ continue;
+ bucket_counts[j]++;
+ bucket_next[i * WORD_DIFF_ALIGN_FINGERPRINT_BITS + j] = bucket_heads[j];
+ bucket_heads[j] = i + 1;
+ }
+ }
+
+ for (i = 0; i < old_items_nr; i++) {
+ int touched_nr = 0;
+ uint64_t old_context;
+
+ if (old_items[i].change_pos < 0)
+ continue;
+ old_context = word_diff_align_window_bits(old_lines, old_items_nr, i);
+ for (j = 0; j < WORD_DIFF_ALIGN_FINGERPRINT_BITS; j++) {
+ uint64_t bit = 1ULL << j;
+ int item;
+
+ if (!(old_context & bit))
+ continue;
+ if (bucket_counts[j] > WORD_DIFF_ALIGN_BIT_BUCKET_MAX)
+ continue;
+ for (item = bucket_heads[j]; item; item = bucket_next[(item - 1) * WORD_DIFF_ALIGN_FINGERPRINT_BITS + j]) {
+ int new_pos = item - 1;
+
+ if (!candidate_counts[new_pos])
+ candidate_touched[touched_nr++] = new_pos;
+ candidate_counts[new_pos]++;
+ }
+ }
+
+ for (j = 0; j < touched_nr; j++) {
+ int new_pos = candidate_touched[j];
+ int filter_score, filter_shared;
+ int window_score, window_shared;
+ int line_score, line_shared, pair_score;
+
+ candidate_counts[new_pos] = 0;
+ if (new_items[new_pos].change_pos < 0)
+ continue;
+ filter_score = word_diff_align_filter_score(old_context,
+ new_contexts[new_pos],
+ &filter_shared);
+ if (filter_score < WORD_DIFF_ALIGN_WINDOW_MIN_SCORE ||
+ filter_shared < WORD_DIFF_ALIGN_WINDOW_MIN_SHARED)
+ continue;
+ window_score = word_diff_align_window_token_score(old_lines,
+ old_items_nr,
+ i,
+ old_tokens,
+ new_lines,
+ new_items_nr,
+ new_pos,
+ new_tokens,
+ &window_shared);
+ if (window_score < WORD_DIFF_ALIGN_WINDOW_MIN_SCORE)
+ continue;
+ pair_score = word_diff_align_pair_score(window_score,
+ &old_lines[i],
+ old_lines,
+ old_items_nr,
+ i,
+ old_tokens,
+ &new_lines[new_pos],
+ new_lines,
+ new_items_nr,
+ new_pos,
+ new_tokens,
+ &line_score,
+ &line_shared);
+ if (pair_score < WORD_DIFF_ALIGN_SCORE_MIN)
+ continue;
+ word_diff_align_add_candidate(&candidates, &candidates_nr,
+ &candidates_alloc, i, new_pos,
+ pair_score, window_score,
+ window_shared, line_score,
+ line_shared);
+ }
+ }
+
+ QSORT(candidates, candidates_nr, word_diff_align_candidate_cmp);
+ for (i = 0; i < candidates_nr; i++) {
+ int old_pos = candidates[i].old_pos;
+ int new_pos = candidates[i].new_pos;
+ int minus_pos = old_items[old_pos].change_pos;
+ int plus_pos = new_items[new_pos].change_pos;
+ int old_len, new_len, edited, moved;
+
+ if (used_old[minus_pos] || used_plus[plus_pos])
+ continue;
+ used_old[minus_pos] = 1;
+ used_plus[plus_pos] = 1;
+ old_len = word_diff_align_payload_len(&e->buf[old_items[old_pos].symbol]);
+ new_len = word_diff_align_payload_len(&e->buf[new_items[new_pos].symbol]);
+ edited = old_len != new_len ||
+ memcmp(e->buf[old_items[old_pos].symbol].line,
+ e->buf[new_items[new_pos].symbol].line,
+ old_len);
+ moved = !word_diff_align_local_pair(old_pos, new_pos);
+ word_diff_align_debug_mark_pair(&e->buf[old_items[old_pos].symbol],
+ &e->buf[new_items[new_pos].symbol],
+ old_items[old_pos].line_no,
+ new_items[new_pos].line_no,
+ edited, moved,
+ candidates[i].window_score,
+ candidates[i].line_score,
+ candidates[i].score);
+ }
+
+cleanup:
+ free(old_items);
+ free(new_items);
+ free(old_lines);
+ free(new_lines);
+ free(old_tokens);
+ free(new_tokens);
+ free(new_contexts);
+ free(bucket_heads);
+ free(bucket_next);
+ free(bucket_counts);
+ free(candidate_counts);
+ free(candidate_touched);
+ free(used_old);
+ free(used_plus);
+ free(candidates);
+}
+
+static void mark_word_diff_align(struct diff_options *o)
+{
+ int i, hunk_start = -1;
+ struct emitted_diff_symbols *e = o->emitted_symbols;
+
+ for (i = 0; i < e->nr; i++) {
+ if (e->buf[i].s == DIFF_SYMBOL_CONTEXT_FRAGINFO) {
+ if (hunk_start >= 0)
+ word_diff_align_hunk(e, hunk_start, i);
+ hunk_start = i + 1;
+ } else if (hunk_start >= 0 &&
+ e->buf[i].s != DIFF_SYMBOL_CONTEXT &&
+ e->buf[i].s != DIFF_SYMBOL_CONTEXT_INCOMPLETE &&
+ e->buf[i].s != DIFF_SYMBOL_CONTEXT_MARKER &&
+ e->buf[i].s != DIFF_SYMBOL_PLUS &&
+ e->buf[i].s != DIFF_SYMBOL_MINUS) {
+ word_diff_align_hunk(e, hunk_start, i);
+ hunk_start = -1;
+ }
+ }
+
+ if (hunk_start >= 0)
+ word_diff_align_hunk(e, hunk_start, e->nr);
+}
+
static void emit_line_ws_markup(struct diff_options *o,
const char *set_sign, const char *set,
const char *reset,
@@ -5245,6 +6014,10 @@ void diff_setup_done(struct diff_options *options)
die(_("options '%s' and '%s' cannot be used together, use '%s' with '%s' and '%s'"),
"--pickaxe-all", "--find-object", "--pickaxe-all", "-G", "-S");
+ if (options->word_diff_align && options->word_diff)
+ die(_("options '%s' and '%s' cannot be used together"),
+ "--word-diff-align", "--word-diff");
+
/*
* Most of the time we can say "there are changes"
* only by checking if there are changed paths, but
@@ -5971,6 +6744,18 @@ static int diff_opt_word_diff_regex(const struct option *opt,
return 0;
}
+static int diff_opt_word_diff_align(const struct option *opt,
+ const char *arg, int unset)
+{
+ struct diff_options *options = opt->value;
+
+ BUG_ON_OPT_ARG(arg);
+ options->word_diff_align = !unset;
+ if (!unset)
+ enable_patch_output(&options->output_format);
+ return 0;
+}
+
static int diff_opt_rotate_to(const struct option *opt, const char *arg, int unset)
{
struct diff_options *options = opt->value;
@@ -6205,6 +6990,9 @@ struct option *add_diff_options(const struct option *opts,
OPT_CALLBACK_F(0, "word-diff-regex", options, N_("<regex>"),
N_("use <regex> to decide what a word is"),
PARSE_OPT_NONEG, diff_opt_word_diff_regex),
+ OPT_CALLBACK_F(0, "word-diff-align", options, NULL,
+ N_("annotate similar moved lines"),
+ PARSE_OPT_NOARG, diff_opt_word_diff_align),
OPT_CALLBACK_F(0, "color-words", options, N_("<regex>"),
N_("equivalent to --word-diff=color --word-diff-regex=<regex>"),
PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_color_words),
@@ -7076,7 +7864,7 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
if (WSEH_NEW & WS_RULE_MASK)
BUG("WS rules bit mask overlaps with diff symbol flags");
- if (o->color_moved && want_color(o->use_color))
+ if ((o->color_moved && want_color(o->use_color)) || o->word_diff_align)
o->emitted_symbols = &esm;
if (o->additional_path_headers)
@@ -7092,14 +7880,19 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
struct mem_pool entry_pool;
struct moved_entry_list *entry_list;
- mem_pool_init(&entry_pool, 1024 * 1024);
- entry_list = add_lines_to_move_detection(o, &entry_pool);
- mark_color_as_moved(o, entry_list);
- if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
- dim_moved_lines(o);
+ if (o->word_diff_align)
+ mark_word_diff_align(o);
+
+ if (o->color_moved && want_color(o->use_color)) {
+ mem_pool_init(&entry_pool, 1024 * 1024);
+ entry_list = add_lines_to_move_detection(o, &entry_pool);
+ mark_color_as_moved(o, entry_list);
+ if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
+ dim_moved_lines(o);
- mem_pool_discard(&entry_pool, 0);
- free(entry_list);
+ mem_pool_discard(&entry_pool, 0);
+ free(entry_list);
+ }
for (i = 0; i < esm.nr; i++)
emit_diff_symbol_from_struct(o, &esm.buf[i]);
diff --git a/diff.h b/diff.h
index 7eb84aadf..b9a20b7f2 100644
--- a/diff.h
+++ b/diff.h
@@ -351,6 +351,7 @@ struct diff_options {
int stat_count;
const char *word_regex;
enum diff_words_type word_diff;
+ int word_diff_align;
enum diff_submodule_format submodule_format;
struct oidset *objfind;
--
2.39.3 (Apple Git-146)
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [RFC PATCH 2/3] diff: render word-diff-align pairs for RFC review
2026-05-27 4:23 [RFC PATCH 0/3] diff: pair edited lines inside moved blocks Keita Oda
2026-05-27 4:24 ` [RFC PATCH 1/3] diff: add word-diff-align line pairing Keita Oda
@ 2026-05-27 4:24 ` Keita Oda
2026-05-27 4:24 ` [RFC PATCH 3/3] t4034: cover moved-and-edited word diff alignment Keita Oda
2 siblings, 0 replies; 4+ messages in thread
From: Keita Oda @ 2026-05-27 4:24 UTC (permalink / raw)
To: git; +Cc: Keita ODA
From: Keita ODA <ainsophyao@gmail•com>
Teach the RFC prototype to render selected --word-diff-align pairs with
word-diff-like markers.
This renderer is deliberately small and local to the RFC. It exists to make
the recovered line pairs inspectable in review output. It is not meant to be
the final UI. A production version should likely reuse the existing word-diff
machinery once the line-pairing question is settled.
The renderer computes a token LCS for the selected pair and marks the unmatched
spans with the familiar plain word-diff delimiters:
[-old-]
{+new+}
Moved selected pairs are also marked with DIFF_SYMBOL_MOVED_LINE so that the
current moved-line coloring can show that the pair came from a moved region.
---
diff.c | 213 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 200 insertions(+), 13 deletions(-)
diff --git a/diff.c b/diff.c
index 6b8744920..8629d4670 100644
--- a/diff.c
+++ b/diff.c
@@ -1811,6 +1811,104 @@ static void word_diff_align_add_candidate(struct word_diff_align_candidate **can
candidate->line_shared = line_shared;
}
+/*
+ * RFC-only formatter for exposing the selected line pairs. The final
+ * presentation should reuse the normal word-diff machinery instead of this
+ * small debug renderer.
+ */
+struct word_diff_align_debug_token {
+ int start;
+ int end;
+};
+
+static void word_diff_align_debug_collect_tokens(const struct emitted_diff_symbol *line,
+ struct word_diff_align_debug_token **tokens,
+ int *tokens_nr, int *tokens_alloc)
+{
+ int len = word_diff_align_payload_len(line);
+ int pos = 0, start, end;
+
+ while (word_diff_align_next_token(line->line, len, &pos, &start, &end)) {
+ ALLOC_GROW(*tokens, *tokens_nr + 1, *tokens_alloc);
+ (*tokens)[*tokens_nr].start = start;
+ (*tokens)[*tokens_nr].end = end;
+ (*tokens_nr)++;
+ }
+}
+
+static void word_diff_align_debug_add_span(struct strbuf *out,
+ const char *open,
+ const char *line, int len,
+ const char *close)
+{
+ if (!len)
+ return;
+ strbuf_addstr(out, open);
+ strbuf_add(out, line, len);
+ strbuf_addstr(out, close);
+}
+
+static int word_diff_align_debug_token_eq(const struct emitted_diff_symbol *a,
+ const struct word_diff_align_debug_token *a_tok,
+ const struct emitted_diff_symbol *b,
+ const struct word_diff_align_debug_token *b_tok)
+{
+ int a_len = a_tok->end - a_tok->start;
+ int b_len = b_tok->end - b_tok->start;
+
+ return a_len == b_len &&
+ !memcmp(a->line + a_tok->start, b->line + b_tok->start, a_len);
+}
+
+static void word_diff_align_debug_rewrite_line(struct emitted_diff_symbol *line,
+ struct word_diff_align_debug_token *tokens,
+ int tokens_nr, int *match_to,
+ const struct emitted_diff_symbol *other,
+ struct word_diff_align_debug_token *other_tokens,
+ const char *open, const char *close)
+{
+ struct strbuf out = STRBUF_INIT;
+ char *old_line = (char *)line->line;
+ int payload_len = word_diff_align_payload_len(line);
+ int other_pos = 0;
+ int other_payload_len = word_diff_align_payload_len(other);
+ int pos = 0, i;
+ size_t new_len;
+
+ for (i = 0; i < tokens_nr; i++) {
+ int other_i = match_to[i];
+ int gap_len, other_gap_len;
+
+ if (other_i < 0)
+ continue;
+ gap_len = tokens[i].start - pos;
+ other_gap_len = other_tokens[other_i].start - other_pos;
+ if (gap_len == other_gap_len &&
+ !memcmp(line->line + pos, other->line + other_pos, gap_len))
+ strbuf_add(&out, line->line + pos, gap_len);
+ else
+ word_diff_align_debug_add_span(&out, open,
+ line->line + pos,
+ gap_len, close);
+ strbuf_add(&out, line->line + tokens[i].start,
+ tokens[i].end - tokens[i].start);
+ pos = tokens[i].end;
+ other_pos = other_tokens[other_i].end;
+ }
+ if (payload_len - pos == other_payload_len - other_pos &&
+ !memcmp(line->line + pos, other->line + other_pos,
+ payload_len - pos))
+ strbuf_add(&out, line->line + pos, payload_len - pos);
+ else
+ word_diff_align_debug_add_span(&out, open, line->line + pos,
+ payload_len - pos, close);
+ strbuf_add(&out, line->line + payload_len, line->len - payload_len);
+
+ line->line = strbuf_detach(&out, &new_len);
+ line->len = (int)new_len;
+ free(old_line);
+}
+
static void word_diff_align_debug_append_comment(struct emitted_diff_symbol *line,
const struct strbuf *suffix)
{
@@ -1835,25 +1933,114 @@ static void word_diff_align_debug_mark_pair(struct emitted_diff_symbol *minus_li
struct emitted_diff_symbol *plus_line,
int minus_lineno, int plus_lineno,
int changed, int moved,
- int window_score,
- int line_score,
- int pair_score)
-{
- struct strbuf suffix = STRBUF_INIT;
+ int window_score,
+ int line_score,
+ int pair_score)
+{
+ struct word_diff_align_debug_token *minus_tokens = NULL, *plus_tokens = NULL;
+ int minus_tokens_nr = 0, minus_tokens_alloc = 0;
+ int plus_tokens_nr = 0, plus_tokens_alloc = 0;
+ int *minus_match_to = NULL, *plus_match_to = NULL;
+ int *lcs = NULL;
+ struct emitted_diff_symbol minus_original = *minus_line;
+ struct emitted_diff_symbol plus_original = *plus_line;
+ int i, j, columns;
if (moved) {
minus_line->flags |= DIFF_SYMBOL_MOVED_LINE;
plus_line->flags |= DIFF_SYMBOL_MOVED_LINE;
}
- strbuf_addf(&suffix,
- " # aligned from %d to %d, %s, W=%d L=%d S=%d",
- minus_lineno, plus_lineno,
- changed ? "edited" : "unchanged",
- window_score, line_score, pair_score);
- word_diff_align_debug_append_comment(minus_line, &suffix);
- word_diff_align_debug_append_comment(plus_line, &suffix);
- strbuf_release(&suffix);
+ minus_original.line = xmemdupz(minus_line->line, minus_line->len);
+ plus_original.line = xmemdupz(plus_line->line, plus_line->len);
+ if (!changed)
+ goto comment;
+
+ word_diff_align_debug_collect_tokens(minus_line, &minus_tokens,
+ &minus_tokens_nr,
+ &minus_tokens_alloc);
+ word_diff_align_debug_collect_tokens(plus_line, &plus_tokens,
+ &plus_tokens_nr,
+ &plus_tokens_alloc);
+ if (!minus_tokens_nr || !plus_tokens_nr)
+ goto comment;
+
+ columns = plus_tokens_nr + 1;
+ CALLOC_ARRAY(lcs, (minus_tokens_nr + 1) * columns);
+ ALLOC_ARRAY(minus_match_to, minus_tokens_nr);
+ ALLOC_ARRAY(plus_match_to, plus_tokens_nr);
+ for (i = 0; i < minus_tokens_nr; i++)
+ minus_match_to[i] = -1;
+ for (j = 0; j < plus_tokens_nr; j++)
+ plus_match_to[j] = -1;
+
+ for (i = 1; i <= minus_tokens_nr; i++) {
+ for (j = 1; j <= plus_tokens_nr; j++) {
+ if (word_diff_align_debug_token_eq(minus_line,
+ &minus_tokens[i - 1],
+ plus_line,
+ &plus_tokens[j - 1]))
+ lcs[i * columns + j] =
+ lcs[(i - 1) * columns + j - 1] + 1;
+ else if (lcs[(i - 1) * columns + j] >
+ lcs[i * columns + j - 1])
+ lcs[i * columns + j] = lcs[(i - 1) * columns + j];
+ else
+ lcs[i * columns + j] = lcs[i * columns + j - 1];
+ }
+ }
+
+ i = minus_tokens_nr;
+ j = plus_tokens_nr;
+ while (i > 0 && j > 0) {
+ if (lcs[i * columns + j] == lcs[i * columns + j - 1]) {
+ j--;
+ } else if (lcs[i * columns + j] ==
+ lcs[(i - 1) * columns + j]) {
+ i--;
+ } else if (word_diff_align_debug_token_eq(minus_line,
+ &minus_tokens[i - 1],
+ plus_line,
+ &plus_tokens[j - 1])) {
+ minus_match_to[i - 1] = j - 1;
+ plus_match_to[j - 1] = i - 1;
+ i--;
+ j--;
+ } else {
+ BUG("word-diff-align display LCS backtrack failed");
+ }
+ }
+
+ word_diff_align_debug_rewrite_line(minus_line, minus_tokens,
+ minus_tokens_nr, minus_match_to,
+ &plus_original, plus_tokens,
+ "[-", "-]");
+ word_diff_align_debug_rewrite_line(plus_line, plus_tokens,
+ plus_tokens_nr, plus_match_to,
+ &minus_original, minus_tokens,
+ "{+", "+}");
+
+comment:
+ {
+ struct strbuf suffix = STRBUF_INIT;
+
+ strbuf_addf(&suffix,
+ " # aligned from %d to %d, %s, W=%d L=%d S=%d",
+ minus_lineno, plus_lineno,
+ changed ? "edited" : "unchanged",
+ window_score, line_score, pair_score);
+ word_diff_align_debug_append_comment(minus_line, &suffix);
+ word_diff_align_debug_append_comment(plus_line, &suffix);
+ strbuf_release(&suffix);
+ }
+
+ free((char *)minus_original.line);
+ free((char *)plus_original.line);
+ free(minus_tokens);
+ free(plus_tokens);
+ free(minus_match_to);
+ free(plus_match_to);
+ free(lcs);
}
static void word_diff_align_add_item(struct word_diff_align_item **items,
--
2.39.3 (Apple Git-146)
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [RFC PATCH 3/3] t4034: cover moved-and-edited word diff alignment
2026-05-27 4:23 [RFC PATCH 0/3] diff: pair edited lines inside moved blocks Keita Oda
2026-05-27 4:24 ` [RFC PATCH 1/3] diff: add word-diff-align line pairing Keita Oda
2026-05-27 4:24 ` [RFC PATCH 2/3] diff: render word-diff-align pairs for RFC review Keita Oda
@ 2026-05-27 4:24 ` Keita Oda
2 siblings, 0 replies; 4+ messages in thread
From: Keita Oda @ 2026-05-27 4:24 UTC (permalink / raw)
To: git; +Cc: Keita ODA
From: Keita ODA <ainsophyao@gmail•com>
Add a focused --word-diff-align test with a moved permission-style block where
one value changes inside the moved block.
The test is intentionally small. It checks that the changed line is paired and
that the RFC renderer exposes the old and new value with word-diff-like
markers.
---
t/t4034-diff-words.sh | 46 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 0be647c2f..7bf696b17 100755
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -148,6 +148,52 @@ test_expect_success '--word-diff=plain' '
word_diff --word-diff=plain --no-color
'
+test_expect_success '--word-diff-align marks moved-and-edited block lines' '
+ cat >old <<-\EOF &&
+ #define LIMIT_PUBLIC_UPLOADS 25
+ #define LIMIT_PUBLIC_INVITES 8
+
+ /* Public resource permissions. */
+ #define PERM_RESOURCE_READ 0x0001
+ #define PERM_RESOURCE_LIST 0x0002
+ #define PERM_RESOURCE_COMMENT 0x0004
+ #define PERM_RESOURCE_EXPORT 0x0008
+ #define PERM_RESOURCE_SHARE 0x0010
+ #define PERM_RESOURCE_ARCHIVE 0x0020
+ #define PERM_RESOURCE_DELETE 0x0040
+ #define PERM_RESOURCE_ADMIN 0x0080
+
+ #define PERM_INTERNAL_DEBUG 0x0100
+ #define PERM_INTERNAL_IMPERSONATE 0x0200
+
+ #define AUDIT_POLICY_STRICT 1
+ #define AUDIT_POLICY_VERBOSE 2
+ EOF
+ cat >new <<-\EOF &&
+ #define LIMIT_PUBLIC_UPLOADS 25
+ #define LIMIT_PUBLIC_INVITES 8
+
+ #define PERM_INTERNAL_DEBUG 0x0100
+ #define PERM_INTERNAL_IMPERSONATE 0x0200
+
+ #define AUDIT_POLICY_STRICT 1
+ #define AUDIT_POLICY_VERBOSE 2
+
+ /* Public resource permissions. */
+ #define PERM_RESOURCE_READ 0x0001
+ #define PERM_RESOURCE_LIST 0x0002
+ #define PERM_RESOURCE_COMMENT 0x0004
+ #define PERM_RESOURCE_EXPORT 0x0001
+ #define PERM_RESOURCE_SHARE 0x0010
+ #define PERM_RESOURCE_ARCHIVE 0x0020
+ #define PERM_RESOURCE_DELETE 0x0040
+ #define PERM_RESOURCE_ADMIN 0x0080
+ EOF
+ test_must_fail git diff --no-index --histogram --word-diff-align old new >actual &&
+ test_grep "^-#define PERM_RESOURCE_EXPORT\\[-.*0x0008-\\]" actual &&
+ test_grep "^+#define PERM_RESOURCE_EXPORT{+.*0x0001+}" actual
+'
+
test_expect_success '--word-diff=plain --color' '
cat >expect <<-EOF &&
<BOLD>diff --git a/pre b/post<RESET>
--
2.39.3 (Apple Git-146)
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-05-27 4:24 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-27 4:23 [RFC PATCH 0/3] diff: pair edited lines inside moved blocks Keita Oda
2026-05-27 4:24 ` [RFC PATCH 1/3] diff: add word-diff-align line pairing Keita Oda
2026-05-27 4:24 ` [RFC PATCH 2/3] diff: render word-diff-align pairs for RFC review Keita Oda
2026-05-27 4:24 ` [RFC PATCH 3/3] t4034: cover moved-and-edited word diff alignment Keita Oda
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox