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preproc: fix infinite loop in paste_tokens with leading/consecutive %+ #321

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preproc: fix infinite loop in paste_tokens with leading/consecutive %+ #321

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edcb8fb
preproc: fix infinite loop in paste_tokens with leading/consecutive %+
Sep 23, 2026
a76c3ff
test: add regression fixture for issue #294 leading/consecutive %+
agourakis82 Sep 24, 2026
b105d3a
test: cover literal and empty-expansion paste hangs in br294
agourakis82 Oct 7, 2026
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9 changes: 6 additions & 3 deletions asm/preproc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5616,6 +5616,10 @@ static bool paste_tokens(Token **head, const struct concat_mask *m,
if (!t) {
/* Nothing to actually paste, just zapping the paste */
*prev_next = tok = next;
if (tok_white(tok) || tok_is(tok, TOKEN_PASTE))
prev_nonspace = NULL;
else
prev_nonspace = prev_next;
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break;
}

Expand Down Expand Up @@ -5695,10 +5699,9 @@ static bool paste_tokens(Token **head, const struct concat_mask *m,
if (did_paste) {
pasted = true;
} else {
prev_next = &tok->next;
if (next && next->type != TOKEN_WHITESPACE &&
next->type != TOKEN_PASTE)
if (!tok_white(tok) && !tok_is(tok, TOKEN_PASTE))
prev_nonspace = prev_next;
prev_next = &tok->next;
}
tok = next;
}
Expand Down
9 changes: 9 additions & 0 deletions travis/br294/br294-paste.asm
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Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
; Literal issue #294 inputs and consecutive pastes after empty expansion.
%+s%+t
%+ts %+ts
%+s%+%+t
%define EMPTY
%+s%+EMPTY%+t
s%+EMPTY%+t
EMPTY %+ st
st %+ EMPTY
9 changes: 9 additions & 0 deletions travis/br294/br294-paste.i.t
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@@ -0,0 +1,9 @@
%line 2+1 ./travis/br294/br294-paste.asm
st
tsts
st

st
st
st
st
7 changes: 7 additions & 0 deletions travis/br294/br294.asm
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Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
; Test for issue #294: leading and consecutive %+ tokens in preprocessor
%define test_lead %+ nop
%define test_consec no %+ %+ p
%define test_both %+ %+ nop
test_lead
test_consec
test_both
1 change: 1 addition & 0 deletions travis/br294/br294.bin.t
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@@ -0,0 +1 @@
���
18 changes: 18 additions & 0 deletions travis/br294/br294.json
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@@ -0,0 +1,18 @@
[
{
"description": "Issue #294: leading and consecutive %+ tokens in preprocessor",
"format": "bin",
"source": "br294.asm",
"target": [
{ "output": "br294.bin" }
]
},
{
"description": "Issue #294: literal reports and consecutive/empty-expansion pastes",
"source": "br294-paste.asm",
"option": "-E",
"target": [
{ "output": "br294-paste.i" }
]
}
]