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Fix import section count when using compact imports - #2870
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Under the compact import section proposal the import section is encoded as `section_2(list(imports))`, where a single `imports` entry can contain multiple imports. The leading count is therefore the number of entries in the section, not the total number of imports. Previously both the writer and the reader used the total number of imports, so modules written by wabt could not be read by other tools and conforming modules (such as those in the proposal's spec tests) were rejected by wabt. - binary-writer: Write the number of entries as the section count. - binary-reader: Loop over the entries, keeping a separate running import index. OnImportCount now reports the number of entries. - wasm-objdump: Count the imports during the prepass so that the total number of imports is still reported. Fixes: WebAssembly#2845
sbc100
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Oct 1, 2026
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So i still counts total imports, is that what we want? Do could we use j here and completely remove i?
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j restarts at 0 for each compact group, but OnImport/OnImport* take the index of the import within the whole section (it shows up in the -v logging output and objdump uses it), so we still need that. However it doesn't need to be tracked separately: ReadImport already bumps exactly one of the per-kind counters for each import, so the index is just their sum. I've removed i from ReadImportSection and the ReadImport parameter, and compute the index there instead.
The index of each import can be derived from the per-kind import counters that ReadImport already maintains, so there is no need to track it separately while iterating over the import section entries.
sbc100
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Oct 2, 2026
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The compact import section proposal encodes the import section as
section_2(list(imports)), where a single entry can contain several imports, so the section count is the number of entries rather than the number of imports. wabt's writer and reader both used the total import count, which made wabt's output unreadable by other decoders and caused wabt to reject conforming modules.OnImportCountnow reports the entry count.--enable-alldump tests would printImport[1]followed by two imports; happy to print the raw entry count and update those tests instead if preferred).test/binary/compact-imports.txt(hand-written binary, now with a single entry after the compact runs) andtest/dump/compact-imports.txt.Non-compact encoding is unchanged.
run-tests.pypasses.Fixes #2845